Isomeric 3-isoxadiazolylcoumarins and their derivatives

Abstract

Here we represent preparative methods of synthesis of isomeric 3-isoxadiazolylcoumarins and their derivatives. Two new synthetic methods have been developed for 3-[1,2,4-oxadiazol-5-yl]coumarins I. The first method is based on a three-component condensation of coumarin-3-carboxylic acids, CDI and amidoximes. The second method essentially uses the interaction of 5-cyanomethyl-1,2,4-oxadiazoles with salicylic aldehydes. General approach for preparation of 3-[1,2,4-oxadiazol-3-yl]coumarins II has been worked out. Moreover, above mentioned synthetic ways open the way for the synthesis of 2-iminoderivatives III and IV not described before, those were diversified by reaction of nucliophilic substitution of 2-imino group with a numerous amino compounds.