Title of Invention: Aminopyrazine derivative and medicine Abstract: The present invention relates to a compound represented by general formula [1] satisfying the following (I) or (II), or a pharmaceutical acceptable salt of the compound. (I) X is CH or N; R1 is a halogen atom, and R2 is H, a halogen atom, CN, [2], [3], [8], [9], an —O-alkyl, an —O-(saturated ring), etc. [2]: —C(RC)(RD)(RE) (RC to RE each are H, an alkyl, etc.) [3]: —N(RF)(RG) (RF and RG each are H, OH, amino, a (hetero)aryl, etc.) [8]: —C(═O)RL (RL is an alkyl, OH, an alkoxy, amino, etc.) [9]: a (substituted)phenyl; (II) X is >C—C(—O)RB (RB is a (substituted)amino, an alkoxy, OH, etc.); R1 is a halogen atom; R2 is H; R3 is H or OH; and R3 and R4 each are H or an alkyl. Detailed Description: Part general_description_paragraphs: Part CROSS-REFERENCE TO RELATED APPLICATIONS: This patent application is a U.S. national stage application under 35 U.S.C. §371 of International Patent Application No. PCT/JP2010/051722 filed on Feb. 5, 2010, which claims the benefit of foreign priority to Japanese Patent Application No. JP 2009-026470 filed on Feb. 6, 2009, and Japanese Patent Application No. JP 2009-276133 filed on Dec. 4, 2009, the disclosures of all of which are hereby incorporated by reference in their entireties. The International Application was published in Japanese on Aug. 12, 2010, as international Publication No. WO 2010/090290 A1 under PCT Article 21 (2). Part FIELD OF THE INVENTION: The present invention relates to a new aminopyrazine derivative and a pharmaceutical composition containing the aminopyrazine derivative as an active ingredient. Part BACKGROUND OF THE INVENTION: Myeloidproliferative neoplasms (chronic myeloid proliferative diseases) are a class of diseases mainly involving abnormal growth of hemocytes, which is caused by aberrant hematopoietic stem cells. Specifically, diseases such as polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis are known (see, for example, Van Etten, et al., 2004, Cancer Cell, 6, 547-552). At present, there is no available therapy for myeloidproliferative neoplasms (chronic myeloid proliferative diseases) and thus there is an earnest desire of therapeutic agent for these diseases. In 2005, an activated mutation of JAK2, a kind of JAK family tyrosine kinases (JAK2 V617F mutation), was reported in a patient suffering from myeloidproliferative neoplasm (chronic myeloid proliferative disease) (see, for example, Robert Kralovics, et al., 2005, New England journal of Medicine, 352, 1779-1790). In a subsequent study, the activated mutation was confirmed in about 95% of polycythemia vera patients, about 50% of essential thrombocythemia patients, and about 50% of idiopathic myelofibrosis patients (see, for example, Peter J. Campbell, et al., 2006, New England Journal of Medicine, 355, 2452-2466). Further, another activated mutation of JAK2 (JAK2 0620E mutation) was found in a few cases of polycythemia vera patients (see, for example, L. Richeldi, et al., 2006, Leukemia, 20, 2210-2211). Moreover, activated mutations of c-Mpl in a thrombopoietin receptor (MPL W515L mutation and MPL W515K mutation) were found in about 10% of idiopathic myelofibrosis patients in whom JAK2 V617F was negative. Since JAK2 is located downstream of the intracellular signal transduction pathway of c-Mpl, a compound having a JAK2 tyrosine kinase inhibitory activity is expected to be an active ingredient for therapeutics in treatment of diseases caused not only by JAK2-activated mutation but also by c-Mpl mutation, e.g., myeloidproliferative neoplasms (chronic myeloid proliferative diseases) (see, for example, Yana Pikman, et al., 2006, PLoS Medicine, 3, 1140-1151, and Animesh D, et al., 2006, Blood, 108, 3472-3476). JAK2-activated mutations have also been found in other than myeloidproliferative neoplasms (chronic myeloid proliferative diseases). For example, it has been reported that a JAK2 V617F mutation is found at a high rate in patients belonging to a class of myelodysplastic syndrome (RARS-T) (see, for example, M M Ceesay, et al., 2006, Leukemia, 20, 2060-2061). JAK2-activated mutation (JAK2 R683S/G mutation etc.) has also been found in 16 (about 9%) of 187 cases in infantile acute lymphocytic leukemia patients (see, for example, C. Mullighan, et al., 2009, Proceedings of the National Academy of Science U.S.A, 106, 9414-9418), and in about 20% of infantile acute lymphocytic leukemia patients with Down's syndrome (see, for example, A. Gaikwad, et al., 2008, British journal of Haematology, 144, 930-932). It has also been reported that the activation of JAK2 tyrosine kinase generated by JAK2 fusion gene is involved in pathological formation. For example, a TEL-JAK2 fusion protein was found in patients of myeloidproliferative neoplasms (acute myeloid proliferative diseases) and of acute myeloid leukemia, and a BCR-JAK2 fusion protein and a PCM1-JAK2 fusion protein were found in patients of chronic myeloid leukemia-like hematic cancer (see, for example, Lyne Valentino, et al., 2006, Biochemical Pharmacology, 71, 713-721 (“Valentino”)). JAK2 signal transduction pathway is involved in the growth of Bcr-Ab1-positive chronic myeloid leukemia cells, suggesting that a compound having a JAK2 tyrosine kinase inhibitory activity will be effective for imatinib-resistant chronic myeloid leukemia (see, for example, Ajoy K. Samanta, et al., 2006, Cancer Research, 66, 6468-6472). In general, the JAK2 signal transduction pathway is one of important pathways in the growth of hematic cancer cell, and thus, a compound having a JAK2 tyrosine kinase inhibitory activity is expected to have a therapeutic effect for a variety of hematic cancers (see, for example, Valentino). JAK2 tyrosine kinase is also involved in intracellular signal transduction of cytokine receptors or hormone receptors. Interleukin-6 (IL-6) is an inflammatory cytokine which plays an important role in inflammation, immunoresponse and onset of cancers (see, for example, H. Yu, et al., 2009, Nature Reviews Cancer, 9, 798-809, H. Ogura, et al., 2008, Immunity, 29, 628-636, and R. Catlett-Falcone, et al., 1999, Immunity, 10, 105-115), and the IL-6 signal is transduced through JAK2 tyrosine kinase (see, for example, M. Narazaki, et al., 1994, Proceedings of the National Academy of Science U.S.A, 91, 2285-2289). Diseases in which IL-6 is involved include inflammatory diseases (e.g., rheumatoid arthritis, inflammatory bowel disease, osteoporosis, multiple sclerosis), hematic cancers (e.g., multiple myeloma), solid cancer (e.g., prostatic cancer), and angiopathy (e.g., pulmonary hypertension, arteriosclerosis, aneurysm, varicose vein) (see, for example, P. Heinrich, et al., 2003, Biochemical Journal, 374, 1-20, M. Steiner, et al., 2009, Circulation Research, 104, 236-244, and H. Alexander, et al., 2009, Biochemical Pharmacology, 78, 539-552). Further, it is known that JAK2 tyrosine kinase contributes to intracellular signal transduction of prolactin receptors, and the expressed amount of prolactin receptor increases in breast cancer, resulting in acceleration of the proliferation of cancer cells by prolactin (for example, L. Neilson, et al., 2007, Molecular Endocrinology, 21, 2218-2232). Thus, it is expected that a compound having a JAK2 tyrosine kinase inhibitory activity exhibits a therapeutic effect for a variety of diseases such as inflammatory diseases, hematic cancers, solid cancers, and angiopathy since JAK2 tyrosine kinase is involved in transduction of extracellular stimulation. JAK3 is a tyrosine kinase which plays an important role in signal transduction of cytokine, and has attracted considerable attention as a target molecule of immunosuppressants since 10 or more years ago. In fact, compounds having a JAK3 tyrosine kinase inhibitory activity have been subjected to clinical trial as therapeutics for organ transplantation and rheumatoid arthritis (see, for example, Paul S. Changelian, et al., 2003, Science, 302, 875-878). Part BRIEF SUMMARY OF TEL INVENTION: The main purpose of the present invention is to provide a new aminopyrazine derivative. Another purpose of the present invention is to provide a pharmaceutical composition which contains such an aminopyrazine derivative as an active ingredient. In the present invention, the compound represented by the following general formula [1] (hereinafter referred to as “the compound of the invention”) or a pharmaceutically acceptable salt thereof is exemplified, wherein the compound is defined by the following (I) or (II). (I): X represents CH or N; R1 represents a halogen; R2 represents: (1) H, (2) a halogen, (3) cyano, (4) a group represented by the following general formula [2]: (wherein * indicates the binding position; and RC, RD and RE are the same or different and each represents (a) H, or (b) alkyl optionally substituted by hydroxy or alkoxy, or alternatively two of RC, RD and RE are taken together with the adjacent C to represent a N-containing saturated heterocyclic group and the other one is H, the saturated heterocyclic group optionally substituted by alkylsulfonyl), (5) a group represented by the following general formula [3]: (wherein * has the same meaning as described above; and RF and RG are the same or different and each represents (a) H, (b) alkyl optionally substituted by one or two groups selected from the group consisting of hydroxy, amino, dialkylamino, a saturated cyclic amino group, alkylcarbonylamino, alkylsulfonylamino, aryl, heteroaryl optionally substituted by alkyl, tetrahydrofuranyl, and carbamoyl, (c) alkylcarbonyl, (d) alkylsulfonyl, (e) carbamoyl, or (f) heteroaryl optionally substituted by alkyl, or alternatively RF and RG are taken together with the adjacent N to represent a saturated cyclic amino group, which may optionally be substituted by one or two groups selected from the group consisting of (a) halogen, (b) cyano, (c) hydroxy, (d) alkyl optionally substituted by one or two groups selected from the group consisting of hydroxy, alkoxy, amino, alkoxycarbonylamino, alkylsulfonylamino, and alkylcarbonylamino, (e) cycloalkyl, (f) haloalkyl, (g) alkoxy, (h) oxo, (i) a group represented by the following general formula [4]: (wherein * has the same meaning as described above; and RH represents alkyl or aryl), (j) a group represented by the following general formula [5]: (wherein * has the same meaning as described above; and RI and RJ are the same or different and each represents H, alkyl, carbamoyl, alkylcarbonyl, or alkylsulfonyl), (k) a group represented by the following general formula [6]: (wherein * has the same meaning as described above; and RK represents alkyl, hydroxy, amino, alkylamino, dialkylamino, cycloalkylamino, (cycloalkyl)alkylamino, (hydroxyalkyl)amino, (alkoxyalkyl)amino, alkoxy, alkylsulfonylamino, or a saturated cyclic amino group), and (l) a saturated cyclic amino group optionally substituted by hydroxy; and the saturated cyclic amino group, which is formed by combining RF, RG and the adjacent N, may form a spiro-linkage with a group represented by the following general formula [7A] or [7B]: (wherein has the same meaning as described above)), (6) a group represented by the following general formula [8]: (wherein * has the same meaning as described above; and RL represents (a) alkyl, (b) hydroxy, (c) alkoxy, (d) saturated cyclic amino group optionally substituted by alkyl or alkylsulfonyl, or (e) an amino optionally substituted by one or two groups selected from the group consisting of alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl; haloalkyl, dialkylaminoalkyl, alkoxyalkyl, and hydroxyalkyl), (7) a group represented by the following general formula [9]: (wherein * has the same meaning as described above; and RM, RN and RO are the same or different and each represents H, halogen, cyano, alkoxy, carbamoyl, sulfamoyl, monoalkylaminosulfonyl, or alkylsulfonyl, or alternatively two of RM, RN and RO are taken together to represent methylenedioxy), (8) —ORP (RP represents an alkyl optionally substituted by a group selected from the group consisting of hydroxy, dialkylamino, alkoxy, tetrahydrofuranyl, and cycloalkyl, or an optionally O-containing saturated cyclic group optionally substituted by hydroxy), or (9) a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl; R3 represents H or hydroxy; R2 represents H or alkyl; and R5 represents H or alkyl; (II): X represents —CRA; RA represents a group represented by the following general formula [10]: (wherein * has the same meaning as described above; and RB represents (a) amino optionally substituted by one or two groups selected from the group consisting of alkyl, cycloalkyl, (cycloalkyl)alkyl, and alkoxyalkyl, (b) alkoxy, (c) hydroxy, or (d) a saturated cyclic amino group); R1 represents a halogen; R2 represents H; R3 represents E or hydroxy; R4 represents H or alkyl; and R5 represents H or alkyl. Among the compounds of the invention, the compound represented by the general formula [1], particularly the compound as defined by the following [i] or [ii], or pharmaceutically acceptable salts thereof, are preferred. [i]: X is CH or N; and R2 is: (1) a group represented by the following general formula [11]: (wherein * has the same meaning as described above; and RF1 and RG1 are the same or different and each represents (a) H, (b) alkyl optionally substituted by one or two groups selected from the group consisting of hydroxy, amino, dialkylamino, a saturated cyclic amino group, alkylcarbonylamino, alkylsulfonylamino, aryl, heteroaryl optionally substituted by alkyl, tetrahydrofuranyl, and carbamoyl, (c) alkylcarbonyl, (d) alkylsulfonyl, (e) carbamoyl, or (f) heteroaryl optionally substituted by alkyl, or alternatively, RF1 and RG1 are taken together with the adjacent N to represent a saturated cyclic amino group, which may optionally be substituted by one or two groups selected from the group consisting of (a) halogen, (b) cyano, (c) hydroxy, (d) alkyl optionally substituted by one or two groups selected from the group consisting of hydroxy, alkoxy, amino, alkoxycarbonylamino, alkylsulfonylamino and alkylcarbonylamino, (e) cycloalkyl, (f) haloalkyl, (g) alkoxy, (h) oxo, (i) a group represented by the following general formula [4]: (wherein * and RH have the same meanings as described above), (j) a group represented by the following general formula [5]: (wherein *, RI and RJ have the same meanings as described above), (k) a group represented by the following general formula [6]: (wherein * and RK have the same meanings as described above), and (l) a saturated cyclic amino group optionally substituted by hydroxyl; (2) a group represented by the following general formula [8]: (wherein * and RL have the same meanings as described above), (3) a group represented by the following general formula [9]: (wherein *, RM, RN and RO have the same meanings as described above), (4) —ORP1 (wherein RP1 represents an alkyl optionally substituted by a group selected from the group consisting of hydroxy, dialkylamino, alkoxy, tetrahydrofuranyl, and cycloalkyl.), or (5) a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl; [ii]: X is —CRA; RA is a group represented by the following general formula [10]: (wherein * and RB have the same meanings as described above); and R2 is H. Among the compounds of the invention, those in which: X is CH; R2 is: (1) a group represented by the following general formula [11]: (wherein *, RF1 and RG1 have the same meanings as described above), (2) a group represented by the following general formula [8]: (wherein * and RL have the same meanings as described above), (3) a group represented by the following general formula [9]: (wherein *, RM, RN and RO have the same meanings as described above), (4) —ORP1 (wherein RP1 has the same meaning as described above), or (5) a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl; or pharmaceutically acceptable salts thereof are particularly preferred. Among the compounds of the invention, the following specific compounds or pharmaceutically acceptable salts thereof are preferred. (1) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperazin-2-one, (2) N—{(S)-1-[2-{[(S)-1-(4-fluorophenyl)ethyl]amino}-6-(pyrazin-2-ylamino)pyrimidin-4-yl]pyrrolidin-3-yl}acetamide, (3) (S)-6-(3,3-difluoroazetidin-1-yl)-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (4) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(1-methyl-1H-pyrazol-4-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (5) (S)—N2′-[1-(4-fluorophenyl)ethyl]-N6′-(pyrazin-2-yl)-3,4′-bipyridine-2′,6′-diamine, (6) (S)—N2′-[1-(4-fluorophenyl)ethyl]-6-methoxy-N6′-(pyrazin-2-yl)-3,4′-bipyridine-2′,6′-diamine, (7) (S)-2′-[1-(4-fluorophenyl)ethylamino]-6′-(pyrazin-2-ylamino)-3,4′-bipyridin-6-ol, (8) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(oxazol-5-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (9) (S)-6-chloro-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl) pyrimidine-2,4-diamine, (10) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[4-(methylsulfonyl)phenyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (11) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(1H-pyrazol-4-yl)pyrimidine-2,4-diamine, (12) (S)-2-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yloxy}ethanol, (13) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(pyridin-3-yl)pyrimidine-2,4-diamine, (14) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(pyridin-2-yl)pyrimidine-2,4-diamine, (15) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(pyridin-4-yl)pyrimidine-2,4-diamine, (16) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidin-2-one, (17) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperazine-2,6-dione, (18) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}tetrahydropyrimidin-2(1H)-one, (19) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(pyrrolidin-1-yl)pyrimidine-2,4-diamine, (20) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-morpholino-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (21) (S)-1-(2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl)imidazolidin-2-one, (22) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(oxazol-5-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (23) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(6-methoxypyridin-3-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (24) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(1H-pyrazol3-yl)pyrimidine-2,4-diamine, (25) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyridin-2-ol, (26) (S)-5-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyridin-2-ol, (27) N—((R)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidin-3-yl)acetamide, (28) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-(1H-pyrazol-4-yl)pyridine-2,6-diamine, (29) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-(1H-pyrazol-3-yl)pyridine-2,6-diamine, (30) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[3-(methylsulfonyl)phenyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (31) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-[4-(methylsulfonyl)phenyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (32) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(1-isopropyl-1H-pyrazol-4-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (33) N—{(S)-1-[2-{[(S)-1-(4-fluorophenyl)ethyl]amino}-6-(pyrazin-2-ylamino)pyridin-4-yl]pyrrolidin-3-yl}acetamide, (34) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-morpholino-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (35) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-thiomorpholinopyridine-2,6-diamine, (36) (S)-3-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}propan-1-ol, (37) (S)—N-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-yl}azetidin-3-yl)acetamide, (38) (S)-6-(azetidin-1-yl)-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (39) (S)-6-(3-fluoroazetidin-1-yl)-N2-[1-(4-fluorophenyl)-ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (40) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-2-one, (41) (S)-4-(1-ethyl-1H-pyrazol-4-yl)-N2-[1-(4-fluoro-phenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (42) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(1-methyl-1H-pyrazol-5-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (43) (S)-4-[1-(cyclopropylmethyl)-1H-pyrazol-4-yl]-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (44) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(thiazol-5-yl)pyrimidine-2,4-diamine, (45) 1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidin-3-ol, (46) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(5-methylthiazol-2-yl)-N6-(pyrazin-2-yl)pyrimidine-2,4,6-triamine, (47) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4,5′-bipyrimidine-2,6-diamine, (48) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(2-methoxythiazol-5-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (49) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(thiazol-2-yl)pyrimidine-2,4-diamine, (50) (S)-5-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}picolinonitrile, (51) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidine-4-carboxamide, (52) (S)-5-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}picolinamide, (53) 4-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperazine-2-carboxamide, (54) 6-(3-aminopyrrolidin-1-yl)-N2-[(S)-1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (55) N-(1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-yl}pyrrolidin-3-yl)methanesulfonamide, (56) (S)-2-({2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}(2-hydroxyethyl)amino)ethan-1-ol, (57) (S)—N2-[2-(dimethylamino)ethyl]-N2-[1-(4-fluorophenyl)ethyl]N6-(pyrazin-2-yl)pyrimidine-2,4,6-triamine, (58) 1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidine-3-carboxamide, (59) (S)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidine-2-carboxamide, (60) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[4-(methylsulfonyl)piperazin-1-yl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (61) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(1H-pyrrol-3-yl)pyrimidine-2,4-diamine, (62) (R)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-4-hydroxypyrrolidin-2-one, (63) N2-[(S)-1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-[(tetrahydrofuran-2-yl)methyl]pyrimidine-2,4,6-triamine, (64) ((S)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidin-2-yl)methanol, (65) ((R)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidin-2-yl)methanol, (66) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidin-4-ol, (67) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-ol, (68) 1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidin-3-ol, (69) (S)-5-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}nicotinonitrile, (70) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(2H-tetrazol-5-yl)pyrimidine-2,4-diamine, (71) (S)—N4-(2-aminoethyl)-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyrimidine-2,4,6-triamine, (72) (S)—N-(2-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-ylamino}ethyl)methanesulfonamide, (73) (S)—N-(2-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-ylamino}ethyl)acetamide, (74) (S)-2-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-ylamino}acetamide, (75) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}benzamide, (76) (S)-3-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}benzonitrile, (77) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(furan-3-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (78) ethyl (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidine-4-carboxylate, (79) (S)-5-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}nicotinamide, (80) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}piperidine-4-carboxylic acid, (81) (S)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino}pyrimidin-4-ylamino)-2-phenylethanol, (82) (S)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-ylamino}-3-phenylpropan-1-ol, (83) (R)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-ylamino}-4-methylpentan-1-ol, (84) (S)—6-[2-(dimethylamino)ethoxy]-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (85) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-1H-pyrazole-4-carboxylic acid, (86) (S)-3-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}benzamide, (87) (S)-6-(benzo[d]1,3-dioxol-5-yl)-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (88) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(2-fluoropyridin-4-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (89) N2-[(S)-1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-[(tetrahydrofuran-2-yl)methoxy]pyrimidine-2,4-diamine, (90) (S)-2-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yloxy}ethanol, (91) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-[2-(pyrrolidin-1-yl)ethyl]pyrimidine-2,4,6-triamine, (92) (S)-3-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}isonicotinamide, (93) (S)-3-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}isonicotinonitrile, (94) (S)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-ylamino}-3-methylbutan-1-ol, (95) (S)—N2-[1-(4-chlorophenyl)ethyl]-6-[4-(methylsulfonyl)piperazin-1-yl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (96) (1S,2S)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yloxy}cyclohexanol, (97) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-[(5-methylpyrazin-2-yl)methyl]-N6-(pyrazin-2-yl)pyrimidine-2,4,6-triamine, (98) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(furan-2-yl-methyl)-N6-(pyrazin-2-yl)pyrimidine-2,4,6-triamine, (99) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-[1-(pyridin-3-yl)ethyl]pyrimidine-2,4,6-triamine, (100) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-4-(hydroxymethyl)piperidin-4-ol, (101) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-(pyridin-2-ylmethyl)pyrimidine-2,4,6-triamine, (102) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-(pyridin-3-ylmethyl)pyrimidine-2,4,6-triamine, (103) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-N6-(pyridin-4-ylmethyl)pyrimidine-2,4,6-triamine, (104) (S)-2-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-ylamino}-3-hydroxypropanamide, (105) (3S,4S)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}pyrrolidine-3,4-diol, (106) N2-[(S)-1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-(1,4-dioxa-8-azaspiro[4.5]decan-8-yl)pyrimidine-2,4-diamine, (107) (S)-8-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-1,3-dioxo-8-azaspiro[4.5]decan-2-one, (108) (S)-4-(1-benzyl-1H-pyrazol-4-yl)-N2-[1-(4-fluoro-phenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (109) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[4-(phenylsulfonyl)piperazin-1-yl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (110) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}benzamide, (111) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-(1H-pyrrol-3-yl)pyridine-2,6-diamine, (112) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-pyridine-2,6-diamine, (113) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(4-methyl-1H-imidazol-1-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (114) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(4-methoxyphenyl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (115) (S)-4-(4-fluorophenyl)-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (116) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-methyl-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (117) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-(methylsulfonyl)piperidine-4-carboxamide, (118) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(furan-3-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (119) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-[4-(methylsulfonyl)piperazin-1-yl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (120) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}-4-(hydroxymethyl)piperidin-4-ol, (121) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}benzenesulfonamide, (122) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-methoxy-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (123) 4-{2-[(1S)-1-(4-fluorophenyl)ethylamino]-6(pyrazin-2-ylamino)pyridin-4-yl}-1λ6,4-thiomorpholin-1,1-dione, (124) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}piperidin-4-ol, (125) (S)-1-(4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyridin-4-yl}-1,4-diazepan-1-yl)ethanone, (126) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-N4-(pyrimidin-2-yl)pyridine-2,4,6-triamine, (127) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-N4-(pyridin-2-yl)pyridine-2,4,6-triamine, (128) N2-[(S)-1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-(1,4-dioxa-8-azaspiro[4.5]decan-8-yl)pyridine-2,6-diamine, (129) methyl (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino) isonicotinate, (130) (S)-4-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-methylbenzenesulfonamide, (131) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(4-methyl-1H-imidazol-1-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (132) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4,N6-di(pyrazin-2-yl)pyridine-2,4,6-triamine, (133) (S)-4-(cyclopropylmethoxy)-N2-[1-(4-fluorophenyl)-ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (134) (S)—N2-[1-(4-fluorophenyl)ethyl]-N2-methyl-4-(1-methyl-1H-pyrazol-4-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (135) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}methanol, (136) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinic acid, (137) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(2-methoxyethoxy)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (138) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidine-4-carbonitrile, (139) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinonitrile, (140) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino) isonicotinamide, (141) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(1,2,4-oxadiazol-3-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (142) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(1,2,4-oxadiazol-3-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (143) methyl (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino) nicotinate, (144) (S)-2-[1-(4-fluorophenyl)ethylamino]-N,N-dimethyl-6-(pyrazin-2-ylamino)isonicotinamide, (145) (S)—N-[2-(dimethylamino)ethyl]-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (146) (S)—N-t-butyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (147) (S)—N-ethyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (148) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}[4-(methanesulfonyl)piperazin-1-yl]methanone, (149) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}(pyrrolidin-1-yl)methanone, (150) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-isopropyl-6-(pyrazin-2-ylamino)isonicotinamide, (151) (S)-1-{2-[(S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-2-carboxamide, (152) (S)—N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)-4-(tetrahydro-2H-pyran-4-yloxy)pyridine-2,6-diamine, (153) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carboxamide, (154) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-(2-hydroxyethyl)-6-(pyrazin-2-ylamino)isonicotinamide, (155) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-methyl-6-(pyrazin-2-ylamino)isonicotinamide, (156) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}(morpholino)methanone, (157) (S)—N-benzyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (158) (S)—N-cyclopropyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (159) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}(4-methylpiperazin-1-yl)methanone, (160) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-(2-methoxyethyl)-6-(pyrazin-2-ylamino)isonicotinamide, (161) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-propyl-6-(pyrazin-2-ylamino)isonicotinamide, (162) (S)—N-cyclopropylmethyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (163) (S)—N-cyclobutyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (164) (S)—N-butyl-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (165) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-isobutyl-6-(pyrazin-2-ylamino)isonicotinamide, (166) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)-N-(2,2,2,-trifluoroethyl)isonicotinamide, (167) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-(3-hydroxypropyl)-6-(pyrazin-2-ylamino)isonicotinamide, (168) (S)—N-(2-ethoxyethyl)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)isonicotinamide, (169) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-methylazetidine-3-carboxamide, (170) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(methoxymethyl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (171) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N,N-dimethylazetidine-3-carboxamide, (172) (S)—N-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)methanesulfonamide, (173) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carbonitrile, (174) 2-(4-fluorophenyl)-2-[4-(1-methyl-1H-pyrazol-4-yl)-6-(pyrazin-2-ylamino)pyridin-2-ylamino]ethanol, (175) (S)—N-ethyl-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carboxamide, (176) (S)—N,N-diethyl-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carboxamide, (177) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}ethanone, (178) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(3-methoxy-azetidin-1-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (179) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-3-methylazetidin-3-ol, (180) (S)-2-[1-(4-fluorophenyl)ethylamino]-N-methyl-6-(pyrazin-2-ylamino)nicotinamide, (181) (S)-2-[1-(4-fluorophenyl)ethylamino]-N,N-dimethyl-6-(pyrazin-2-ylamino)nicotinamide, (182) (S)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino) nicotinamide, (183) (S)-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-3-yl}(morpholino)methanone, (184) (S)—N-(cyclopropylmethyl)-2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)nicotinamide, (185) (S)—N-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-yl}azetidin-3-yl)ethanesulfonamide, (186) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-isopropylazetidine-3-carboxamide, (187) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-3-(trifluoromethyl)azetidin-3-ol, (188) (S)-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)(pyrrolidin-1-yl)methanone, (189) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-(2-methoxyethyl)azetidine-3-carboxamide, (190) (S)-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)(piperidin-1-yl)methanone, (191) (S)-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)(morpholino)methanone, (192) (S)—N-(cyclopropyl)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carboxamide, (193) (S)—N-(cyclopropylmethyl)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidine-3-carboxamide, (194) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-N-(2-hydroxyethyl)azetidine-3-carboxamide, (195) (S)-3-cyclopropyl-1-{2-[1-(4-fluorophenyl)ethyl-amino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-ol, (196) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-3-isopropylazetidin-3-ol, (197) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}azetidin-3-ol, (198) (S)-3-cyclopropyl-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}azetidin-3-ol, (199) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}-3-isopropylazetidin-3-ol, (200) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}-3-methylazetidin-3-ol, (201) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}-3-(trifluoromethyl)azetidin-3-ol, (202) (S)-4-(3,3-difluoroazetidin-1-yl)-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (203) (S)—N-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}acetamide, (204) (S)—N-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}methanesulfonamide, (205) (S)-1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}urea, (206) (S)-4-(3-cyclopropyl-3-methoxyazetidin-1-yl)-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (207) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(3-isopropyl-3-methoxyazetidin-1-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (208) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(3-methoxy-3-methylazetidin-1-yl)-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (209) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-(1-methyl-1H-pyrazol-4-yl)-N6-(5-methylpyrazin-2-yl)pyridine-2,6-diamine, (210) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-[1-(methanesulfonyl)piperidin-4-yl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (211) (S)—N-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyridin-4-yl}propionamide, (212) (S)-N2-[1-(4-fluorophenyl)ethyl]-4-[1-(2-methoxyethyl)-1H-pyrazol-4-yl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (213) (S)-4-(1-cyclopropyl-1H-pyrazol-4-yl)-N2-[1-(4-fluorophenyl)ethyl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (214) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-[1-(methoxymethyl)-1H-pyrazol-4-yl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, (215) (S)-6-[3-(dimethylamino)azetidin-1-yl]-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (216) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[3-(methylamino)azetidin-1-yl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (217) (S)—N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)-6-[3-(pyrrolidin-1-yl)azetidin-1-yl]pyrimidine-2,4-diamine, (218) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-(3-morpholinoazetidin-1-yl)-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (219) (S)—N2-[1-(4-fluorophenyl)ethyl]-6-[3-(4-methylpiperazin-1-yl)azetidin-1-yl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (220) (S)-(1-{1-[2-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)piperidin-4-ol, (221) 4-{2-[(1S)-1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}-1λ6,4-thiomorpholin-1,1-dione, (222) (S)-1-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyrimidin-4-yl}azetidin-3-yl)urea, (223) (S)-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)methanol, (224) t-butyl (S)-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)methylcarbamate, (225) (S)-6-[3-(aminomethyl)azetidin-1-yl]-N2-[1-(4-fluorophenyl)ethyl]-N4-(pyrazin-2-yl)pyrimidine-2,4-diamine, (226). (S)—N-[(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)methyl]ethanesulfonamide, (227) (S)—N-[(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-ylamino)pyrimidin-4-yl}azetidin-3-yl)methyl]acetamide, (228) (S)—N2-[1-(4-fluorophenyl)ethyl]-4-[3-morpholinoazetidin-1-yl]-N6-(pyrazin-2-yl)pyridine-2,6-diamine, and (229) (S)-1-(1-{2-[1-(4-fluorophenyl)ethylamino]-6-(pyrazin-2-yl amino)pyridin-4-yl}azetidin-3-yl)piperidin-4-ol. The compounds of the invention or their pharmaceutically acceptable salts are useful as medicaments. The following will describe in detail each term concerned in the invention. “Halogen” includes, for example, fluorine, chlorine, bromine and iodine. “Alkyl” means, for example, a straight or branched chain alkyl having 1 to 8 carbons, specifically including methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, and n-octyl. In particular, those of 1 to 6 carbons are preferred, and those of 1 to 3 carbons more preferred. The alkyl moiety of “alkylsulfonyl”, “alkylcarbonylamino”, “hydroxyalkyl”, “(cycloalkyl)alkyl”, “alkoxyalkyl”, “alkylamino”, “(hydroxyalkyl)amino”, “(alkoxyalkyl)amino”, “dialkylamino”, dialkylaminoalkyl”, “(cycloalkyl)alkylamino”, “alkylcarbonyl”, “alkylcarbonylamino”, “alkylsulfonyl”, “alkylsulfonylamino”, and “monoalkylaminosulfonyl” can be exemplified by the same ones as the above-described “alkyl”. “Haloalkyl” means, for example, a straight or branched chain alkyl of 1 to 8 carbons on which one or more of halogen atoms are substituted at any replaceable optional position (s). The alkyl and halogen moieties of “haloalkyl” can be exemplified by the same ones as the above “alkyl” and “halogen”, respectively. “Cycloalkyl” means, for example, those having 3 to 8 carbons, specifically including cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. The cycloalkyl moiety of “(cycloalkyl)alkyl”, “cycloalkylamino” and “(cycloalkyl)alkylamino” can be exemplified by the same ones as the above “cycloalkyl”. “Alkoxy” means, for example, a straight or branched chain alkoxy having 1 to 8 carbons, specifically including methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, n-Pentyloxy, n-hexyloxy, n-heptyloxy, and n-octyloxy. The alkoxy moiety of “alkoxyalkyl” and “(alkoxyalkyl)amino” is exemplified by the same ones as the above “alkoxy”. “Aryl” means those having 6 to 10 carbons, including for example phenyl, 1-naphthyl, and 2-naphthyl. In particular, phenyl is preferred. “Aralkyl” means, for example, a straight or branched chain alkyl of 1 to 8 carbons on which an aryl of 6 to 10 carbons is substituted at any replaceable optional position, including for example benzyl, phenylethyl (e.g. 1-phenylethyl, 2-phenylethyl), phenylpropyl (1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, etc.), and naphthylmethyl (e.g. 1-naphthylmethyl, 2-naphthylmethyl, etc.). “Saturated cyclic amino group” means, for example, a 4- to 7-membered saturated cyclic amino group which may contain one of O or S with one or two of N as ring-constituting atoms, specifically including 1-azetidinyl, 1-pyrrolidinyl, 1-imidazolidinyl, piperidino, 1-piperazinyl, 1-tetrahydropyrimidinyl, morpholino, thiomorpholino, and 1-homopiperazinyl. “N-containing saturated heterocyclic group” means, for example, a 5- or 6-membered saturated heterocyclic group containing one of N as a ring-constituting atom, specifically including for example 2-pyrrolidinyl, 3-pyrrolidinyl, 2-piperidinyl, 3-piperidinyl, and 4-piperidinyl. “Optionally O-containing saturated cyclic group” means, for example, a 5- or 6-membered saturated cyclic group which may contain one of O as a ring-constituting atom, specifically including for example cyclopentyl, cyclohexyl, tetrahydrofuranyl, and tetrahydropyranyl. “Heteroaryl” means, for example, 5- or 6-membered heteroaryl containing 1 to 4 of N, O and S as (a) ring-constituting atom(s), specifically including for example furyl (e.g. 2-furyl, 3-furyl), thienyl (e.g. 2-thienyl, 3-thienyl), pyrrolyl (e.g. 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl), imidazolyl (e.g. 1-imidazolyl, 2-imidazolyl, 4-imidazolyl), pyrazolyl (e.g. 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl), triazolyl (e.g. 1,2,4-triazol-1-yl, 1,2,4-triazol-3-yl, 1,2,4-triazolyl-4-yl), tetrazolyl (e.g. 1-tetrazolyl, 2-tetrazolyl, 5-tetrazolyl), oxazolyl (e.g. 2-oxazolyl, 4-oxazolyl, 5-oxazolyl), isoxazolyl (e.g. 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl), oxadiazolyl (e.g. 1,3,4-oxadiazol-2-yl), triazolyl (e.g. 2-thiazolyl, 4-thiazolyl, 5-thiazolyl), thiadiazolyl, isothiazolyl (e.g. 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl), pyridyl (e.g. 2-pyridiyl, 3-pyridyl, 4-pyridyl), pyridazinyl (e.g. 3-pyridazinyl, 4-pyridazinyl), pyrimidinyl (e.g. 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl), and pyrazinyl (e.g. 2-pyrazinyl). “Tetrahydrofuranyl” includes, for example, 2-tetrahydrofuranyl and 3-tetrahydrofuranyl. “Tetrahydropyranyl” includes, for example, 2-tetrahydropyranyl, 3-tetrahydropyranyl, and 4-tetrahydropyranyl. Part DETAILED DESCRIPTION OF THE INVENTION: The compounds of the invention can be produced from known compounds or from readily synthesizable intermediates, for example, according to the following processes. In producing the compounds of the invention, when the starting material has a substituent influencing the reaction, the reaction is usually carried out after preliminary protection of the starting material with a suitable protecting group according to a known method. The protecting group may be removed after the reaction completion according to a known method. Process 1: In the Case of R2 Being Halogen (wherein R1 and R5 have the same meanings as described above; X1 represents CH or N; and Hal1 and Hal2 are the same or different, and each represents halogen.) The reaction is a condensation reaction of Compound [12] with Compound [13] using a palladium catalyst and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 1,1′-bis-(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis[2-(diphenylphosphino)phenyl]ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Compound [12] as a starting material may be produced according to a known method (Bioorg. Med. Chem. Lett., 14, 2004, 4249-4252; Org. Lett., 6, 2004, 3671-3674). Process 2: In the Case of R2 being —ORP (Wherein RP has the Same Meaning as Described Above.) Process 2-1 (wherein X1, R1, R5, and Hal2 have the same meanings as described above; and R6 represents an alkyl optionally substituted by a group selected from the group consisting of hydroxy, dialkylamino, alkoxy, tetrahydrofuranyl and cycloalkyl, or an optionally O-containing saturated cyclic group.) The reaction is carried out by condensing Compound [1a] with an alcohol compound [14] using a palladium catalyst. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, and bis[2-(diphenylphosphino)phenyl]ether. The usable base includes, for example, sodium t-butoxide and tripotassium phosphate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Process 2-2 (wherein X1, R1, R5, R6 and Hal1 have the same meanings as described above.) The reaction is a condensation reaction of Compound [15] with Compound [13] using a palladium catalyst and thus may be carried out in the same manner as in Process 1 as mentioned above. Compound [15] as a starting compound may be produced, for example, according to the following method. (wherein X1, R1, R6, Hal1 and Hal2 have the same meanings as described above.) Step 1 Compound [18] may be produced by reacting Compound [16] with an alcohol compound [17] in a suitable solvent in the presence of a base at a temperature of −20° C. to 100° C. The usable base includes, for example, sodium hydride, sodium hydroxide, and the like. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; water; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 30 minutes to 24 hours. Step 2 The reaction is a condensation reaction of Compound [18] with Compound [19] using a palladium catalyst and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis[2-(diphenylphosphino)phenyl]ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Process 3: In the Case of R2 being Represented by the Following General Formula [9] (wherein RM, RN, RO and * have the same meanings as described above), or in the case of R2 being a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl (but the bonding site is limited to C.) Process 3-1 (wherein X1, R1, R5 and Hal2 have the same meanings as described above; and R7 and R8 each represent hydroxy, or R7 and R8 are taken together to represent —O—C(CH3)2—C(CH3)2—O—, —O—(CH2)3—O—, or —O—CH2—C(CH3)2—CH2—O—; and R9 represents a group represented by the following general formula [9]: (wherein RM, RN, RO and * have the same meanings as described above), or a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl (but the bonding site is limited to C).) The reaction is a cross-coupling reaction using Compound [1a] and an organoborane compound [20], and thus may be carried out per se according to a known method. The reaction may be carried out, for example, in the presence of a palladium catalyst and a base in a suitable solvent at 20-200° C. The usable palladium catalyst includes, for example, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, and 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane complex. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; alcohols such as methanol, ethanol; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; water; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The usable base includes, for example, sodium hydroxide, potassium carbonate, and sodium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 30 minutes to 24 hours. Process 3-2 (wherein X1, R1, R5, R9 and Hal1 have the same meanings as described above.) The reaction is a condensation reaction of Compound [21] with Compound [13] using a palladium catalyst and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 1,1′-bis(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis(2-(diphenylphosphino)phenyl)ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Compound [21] as a starting compound may be produced, for example, according to the following 3 processes. Process A (wherein X1, R1, R7, R8, R9, Hal1 and Hal2 have the same meanings as described above; and Hal3 represents a halogen.) Step 1 The reaction is a cross-coupling reaction using Compound [22] and an organoborane compound [20], and thus may be carried out per se according to a known method. The reaction may be carried out, for example, in the presence of a palladium catalyst and a base in a suitable solvent at a temperature of 20-200° C. The usable palladium catalyst includes, for example, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, and 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane complex. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; alcohols such as methanol, ethanol; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; water; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The usable base includes, for example, sodium hydroxide, potassium carbonate, and sodium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 30 minutes to 24 hours. Step 2 The reaction is a condensation reaction of Compound [23] with Compound [19] using a palladium catalyst and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis[2-(diphenylphosphino)phenyl]ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Process B (wherein X1, R1, R9, Hal1 and Hal2 have the same meanings as described above; and R10, R11 and R12 are the same or different and each represents alkyl.) The reaction is a cross-coupling reaction using Compound [12] and an organotin compound [24], and thus may be carried out per se according to a known method. The reaction may be carried out, for example, in the presence of a palladium catalyst in a suitable solvent at 20-200° C. The usable palladium catalyst includes, for example, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane complex, and palladium acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. It is also possible to add an additive such as copper oxide or silver oxide. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 1 to 24 hours. Process C (wherein X1, R1, R7, R8, R9, Hal1 and Hal2 have the same meanings as described above.) The reaction is a cross-coupling reaction using Compound [12] and an organoborane compound [20], and thus may be carried out per se according to a known method. The reaction may be carried out, for example, in the presence of a palladium catalyst and a base in a suitable solvent at a temperature of 20-200° C. The usable palladium catalyst includes, for example, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, and 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane complex. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable reaction solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; alcohols such as methanol, ethanol; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; water; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The usable base includes, for example, sodium hydroxide, potassium carbonate, and sodium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 30 minutes to 24 hours. Process 4: In the Case of R2 being Represented by the Following General Formula [3] (wherein RF and RG each have the same meanings as described above.) Process 4-1 (wherein X1, R1, R5 and Hal2 each have the same meanings as described above; and R13 is a group represented by the following general formula [3]: (wherein RF and RG each have the same meanings as described above).) The reaction is a cross-coupling reaction using Compound [1a] and Compound [25], and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction may be carried out, for example, in the presence of a palladium catalyst and a base in a suitable solvent at a temperature of 20-200° C. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 1,1′-bis-(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis[2-(diphenylphosphino)phenyl]ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 30 minutes to 24 hours. Process 4-2 (wherein X1, R1, R5, R13 and Hal1 each have the same meanings as described above.) The reaction is a condensation reaction of Compound [26] with Compound [13] using a palladium catalyst and thus may be carried out per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction is carried out at a temperature of 20° C. to 200° C. in the presence of a base. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 1,1′-bis-(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis(2-(diphenylphosphino)phenyl)ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Compound [26] as a starting compound may be produced, for example, according to the following 2 processes. (wherein X1, R1, R13, Hal1 and Hal2 each have the same meanings as described above.) Process a Compound [26] may be produced by reacting Compound [12] with Compound [25] in a suitable solvent in the presence of a base at a temperature of 20° C. to 200° C. The usable base includes, for example, pyridine, triethylamine, N,N-diisopropylethylamine, potassium carbonate, and sodium bicarbonate. The usable solvent includes alcohols such as 1-butanol, 2-methoxyethanol; ethers such as tetrahydrofuran, 1,4-dioxane; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; acetonitrile; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction time depends on the kind of the starting material used and the reaction temperature, and in general it is preferably in the range of 1 to 24 hours. Process b Compound [26] can be produced by condensation reaction of Compound [12] with Compound [25] using a palladium catalyst per se according to a known method. The usable solvent includes, for example, hydrocarbons such as toluene, xylene; ethers such as 1,4-dioxane, tetrahydrofuran; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction may be carried out in the presence of a base at a temperature of 20° C. to 200° C. The usable palladium catalyst includes, for example, tris(dibenzylideneacetone)(chloroform)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0), and palladium(II)acetate. The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. The usable ligand for the palladium catalyst includes, for example, 1,1′-bis-(diphenylphosphino)ferrocene, 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, 2-(di-t-butylphosphino)biphenyl, bis[2-(diphenylphosphino)phenyl]ether, and tri-t-butylphosphine. The usable base includes, for example, sodium t-butoxide, tripotassium phosphate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and is usually in the range of 10 minutes to 24 hours. Process 5: in the Case of R2 being a Heteroaryl Optionally Substituted by One or Two Groups Selected from the Group Consisting of Cyano, Halogen, Hydroxy, Alkoxy, Alkylcarbonyl, Carbamoyl, Alkyl, Cycloalkyl, (Cycloalkyl)Alkyl, Aralkyl, Hydroxycarbonyl and Alkoxyalkyl (but the Bonding Site is Limited to N.) (wherein X1, R1, R5 and Hal1 each have the same meanings as described above; and R14 is a heteroaryl optionally substituted by one or two groups selected from the group consisting of cyano, halogen, hydroxy, alkoxy, alkylcarbonyl, carbamoyl, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, hydroxycarbonyl and alkoxyalkyl (but the bonding site is limited to N).) The reaction is a condensation reaction of Compound [27] with Compound [13] using a palladium catalyst, and may be carried out in the same manner as in Process 4-2 as mentioned above. Compound [27] as a starting compound may be produced according to the following method. (wherein X1, R1, R14, Hal1 and Hal2 each have the same meanings as described above.) The reaction is a cross-coupling reaction using Compound [12] and Compound [28], and may be carried out per se according to a known method. The reaction may be carried out, for example, in the presence or absence of a copper catalyst in a proper solvent at a temperature of 20 to 200° C. The usable copper catalyst includes, for example, copper iodide and copper acetate. The amount of the copper catalyst to be used is preferably in the range of 0.01 to 0.2 mole for 1 mole of the aryl halide. The ligand for copper such as trans-N,N′-dimethylcyclohexane-1,2-diamine, trans-1,2-cyclohexanediamine, 1,10-phenanthroline, etc. may be used. The usable reaction solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane; alcohols such as methanol, ethanol; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; hydrocarbons such as benzene, toluene; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The usable base includes, for example, tripotassium phosphate, potassium carbonate, sodium carbonate, and cesium carbonate. The reaction time depends on the kind of the starting material used and the reaction temperature, and in general it is preferably in the range of 30 minutes to 24 hours. Process 6: In the Case of R2 being Alkoxycarbonyl (wherein X1, R1, R5 and Hal1 each have the same meanings as described above; and R15 represents an alkyl.) The reaction is a condensation reaction of Compound [29] with Compound [13] using a palladium catalyst, and may be carried out in the same manner as in Process 4-2 as mentioned above. Compound [29] as a starting compound may be produced according to the following method. (wherein X1, R1, R15, Hal1 and Hal3 each have the same meanings as described above.) The reaction is a condensation reaction of Compound [30] with Compound [19] using a palladium catalyst, and may be carried out in the same manner as in Step 2 in the process for producing Compound [15] as a starting compound as mentioned above. Process 7: In the Case of R2 being Hydroxycarbonyl (wherein X1, R1, R5 and R15 each have the same meanings as described above.) The reaction is a hydrolysis reaction of Compound [1f] and may be carried out per se according to a known method. In general, the reaction can be carried out by hydrolyzing Compound [1f] in the presence of an acid or base to yield Compound [1g]. The acid used in the reaction includes, for example, inorganic acids such as hydrochloric acid and sulfuric acid; the base includes, for example, inorganic bases such as sodium hydroxide and potassium hydroxide. The solvent usable in the reaction includes, for example, alcohols such as methanol, ethanol; ethers such as tetrahydrofuran, 1,4-dioxane; water; or a mixture of them. The reaction is conducted at a temperature of 0° C. to 100° C., usually for a period of 30 minutes to 24 hours. Process 8: In the Case of R2 being (a) a Saturated Cyclic Amino Group Optionally Substituted by Alkyl or Alkylsulfonyl; or (b) an Aminocarbonyl Optionally Substituted by One or Two Groups Selected from the Group Consisting of Alkyl, Cycloalkyl, (Cycloalkyl)Alkyl, Aralkyl, Haloalkyl, Dialkylaminoalkyl, Alkoxyalkyl, and Hydroxyalkyl (wherein X1, R1 and R5 each have the same meanings as described above; R16 and R17 are the same or different and each represents H, alkyl, cycloalkyl, (cycloalkyl)alkyl, aralkyl, haloalkyl, dialkylaminoalkyl, alkoxyalkyl, or hydroxyalkyl, or they are taken together with the adjacent N to represent a saturated cyclic amino group; said saturated cyclic amino group may optionally be substituted by alkyl or alkylsulfonyl.) The reaction is a condensation reaction of Compound [1g] with Compound [31], and can be carried out per se according to a known method. Compound [1h] can be synthesized by reacting Compound [1g] as a carboxylic acid or a reactive derivative thereof with Compound [31]. The reactive derivative of Compound [1g] includes those conventionally used in the amide condensation reaction, for example, acid halides (e.g. acid chloride, acid bromide), mixed acid anhydrides, imidazolides, active amide, and the like. In case of using Compound [1g], the reaction is carried out in the presence or absence of a base using a condensing agent at a temperature of −20 to 100° C. The condensing agent usable in the reaction includes, for example, 1,1′-oxalyldiimidazole, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, dicyclohexylcarbodiimide, diethyl cyanophosphate, O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophospate, and 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate. The base usable in the reaction includes organic base, for example, triethylamine, N,N-diisopropylethylamine, N,N-dimethylanline, pyridine, and 1,8-diazabicyclo[5.4.0]-7-undecene. The usable solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane, diethyl ether; amides such as N,N-dimethylformamide, N,N-dimethylacetamide; nitriles such as acetonitrile, propionitrile; hydrocarbons such as benzene, toluene; halogenated hydrocarbons such as chloroform, methylene chloride; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. If required, an additive may be used. The usable additive includes, for example, 1-hydroxybenzotriazole and 1-hydroxy-7-azabenzotriazole. The reaction time depends on the kind of the starting material used and the reaction temperature, and in general it is preferably in the range of 10 minutes to 24 hours. The amount of Compound [31] and the condensing agent is preferably, for example, in the range of 1 equimolar to 3 equimolar amount for 1 mole of Compound [1g]. Process 9: in the Case of R2 being H, Alkylcarboyl, an N-Containing Saturated Heterocyclic Group Optionally Substituted by Alkylsulfonyl or an Alkyl Optionally Substituted by Hydroxy or Alkoxy (wherein X1, R1, R5 and Hal1 each have the same meanings as described above; and R18 represents H or alkyl optionally substituted by alkoxy.) The reaction is a condensation reaction of Compound [32] with Compound [13] using a palladium catalyst, and can be carried out in the same manner as in Process 1 as mentioned above. Process 10: in the Case of R2 being Cyano (wherein X1, R1, R5 and Hal2 each have the same meanings as described above.) The reaction is a cyanation reaction of Compound [1a], and can be carried out per se according to a known method. The reaction may be carried out using a cyano compound, for example, in the presence or absence of a palladium catalyst at a temperature of 20 to 200° C., if required under microwave. The usable palladium catalyst includes, for example, tetrakis(triphenylphosphine)palladium, 1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloride-dichloromethane complex, and tris(dibenzylideneacetone)dipalladium(0). The amount of the palladium catalyst to be used is preferably within the range of 0.001-0.1 mole for 1 mole of the aryl halide. If required, a palladium ligand such as 4,5-bis(diphenylphosphino)-9,9′-dimethylxanthene, 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl, and the like may be used. The usable cyano compound includes copper (I) cyanide, zinc(II) cyanide, potassium cyanide, and sodium cyanide. The usable solvent includes, for example, ethers such as tetrahydrofuran, 1,4-dioxane; alcohols such as methanol, ethanol; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone; hydrocarbons such as benzene, toluene; dimethylsulfoxide; water; or a mixture of them, but there is no particular limitation as long as they have no influence on the reaction. The reaction time depends on the kind of the starting material used and the reaction temperature, and in general it is preferably in the range of 30 minutes to 24 hours. Process 11: in the Case of X being —CRA, and RA being Alkoxycarbonyl (wherein R1, R5 and Hal1 each have the same meanings as described above; and R19 represents an alkyl.) The reaction is a condensation reaction of Compound [33] with Compound [13] using a palladium catalyst, and can be carried out in the same manner as in Process 4-2 as mentioned above. Compound [33] as a starting compound may be produced according to the following method. (wherein R1, R19, Hal1 and Hal3 each have the same meanings as described above.) The reaction is a condensation reaction of Compound [34] with Compound [19] using a palladium catalyst, and can be carried out in the same manner as in Step 2 of Process A, Process 3-2 as mentioned above. Process 12: in the Case of X being —CRA, and RA being Hydroxycarbonyl (wherein R1, R5 and R19 each have the same meanings as described above.) The reaction is a hydrolytic reaction of Compound [1k] and can be carried out in the same manner as in Process 7 as mentioned above. Process 13: in the Case of X being —CRA; and RA being a Group as Represented by the General Formula [35] (wherein * has the same meaning as described above; R20 and R21 are the same or different, and each represents H, alkyl, cycloalkyl, (cycloalkyl)alkyl, or alkoxyalkyl, or they are taken
{'bibliographic_information': "{'country': 'US', 'doc-number': '13147001', 'kind': 'B2', 'date': '20100205', 'extension': '177', 'invention_title': 'Aminopyrazine derivative and medicine'}", 'source_file': './grant/2014/ipg140318.xml', 'source_data': 'USPTO-Grant'}