Synthesis and Antioxidant Activity of Alkyl N-(9H-Thioxanthen-9-yl)(cyclo)alkylhydrazides

A series of new alkyl N-(9H-thioxanthen-9-yl)(cyclo)alkylhydrazides was obtained for the first time by the reaction of (cyclo)alkylhydrazides, 9H-thioxanthen-9-ol and pyridinium perchlorate in a pyridine medium. The antioxidant activity of alkyl N-(9H-thioxanthen-9-yl)(cyclo)alkylhydrazides was studied. The greatest antioxidant effect was revealed in linear and cyclic N-(9H-thioxanthen-9-yl)(cyclo)alkylhydrazides, the values of which are in the range of 0.72–0.88 from ascorbic acid. The presence of a branched radical in N-(9H-thioxanthen-9-yl)alkylhydrazides significantly reduces the antioxidant properties.