As illustrated in Scheme 1, treatment of acid 3 with either thionyl chloride or oxalyl chloride to produce an intermediate MA-chloride acid followed by exposure to silybin in the presence of triethylamine (TEA) led to the formation of esters 4 and 5, in which compound 5 showed a dehydration of hydroxyl group at C-3 on silybin by the appearance of a signal of singlet proton H-3 at ẟH 6.56 and carbon atom C-3 at ẟC 104.38 . The selective attachment to the 7-OH group of silybin was confirmed based on NMR analysis. This result was in agreement with the report by Křen and Decker . On the other hand, under Steglich conditions using DCC/DMAP, esterification of acid 3 with silybin 1 provided ester 6 with a selective attachment to the 3-OH group of silybin. The NMR analysis of ester 6 confirmed an elimination of protons H-2 and H-3 on the silybin moiety, which took part in an oxidation under mild basic conditions to create 2,3- dehydrosilybin derivatives. The conclusion was based on the disappearance of proton signals at ẟH 5.0 , together with carbon signals at δC 84.7 (C-2) and at δC 73.7 , accompanied by the appearance of two new carbon signals upfield at ẟC 156.7 (C-2) and 132.5 (Scheme 1).