It is known that tantalum compounds can be useful for the synthesis of various classes of organic compounds. The TaCl 5 -Mg reagent system is an effective tool for the reduction of nonfunctionalized alkynes and 1-alkynyl sulfones to the corresponding olefins . Recently, we have developed a regio-and stereoselective method for the synthesis of substituted 3-alkenyl amines and 4-alkynylols based on the reduction of alkynyl amines and alcohols using a similar reagent system NbCl 5 -Mg . The possibility of creating a new carbon-carbon bond was demonstrated by the example of the TaCl 5 -catalyzed carbomagnesiation reaction of 1-alkenes with n-alkyl Grignard reagents . Thus, low-valence tantalum complexes are effective reagents for the transformation of the triple bond of various acetylenic compounds. The closest electronic analogue of the tantalum atom is niobium. According to , NbCl 5 promotes the conversion of carboxylic acids into carboxamides. In this work, in order to study the possibility of conversion of carboxylic acids under the conditions of organotantalum synthesis, we studied the reaction of carboxylic acids with secondary amines in the presence of catalytic amounts of TaCl 5 .