Glycosides of 4-[2-(Hydroxyphenyl)ethen-1-yl]-1,2,3-thia- and Selenodiazoles Based on Natural 4-(Hydroxyphenyl)but-3-en-2-ones

Abstract

In this work, 4-[2-(3- and 4-hydroxyphenyl)ethen-1-yl]-1,2,3-thia- and selenodiazoles were obtained based on natural 4-(hydroxyphenyl)but-3-en-2-ones. Under the conditions of the phase-transfer catalyzed version of the Königs–Knorr reaction, 4-[2-(4-hydroxyphenyl)ethen-1-yl]-1,2,3-thiadiazole forms β-glycosides with low yields, while 4-[2-(3-hydroxyphenyl)ethen-1-yl]-1,2,3-thiadiazole forms labile α-glycosides. Selenodiazole analogs decompose under the reaction conditions. β-Glycosides of 4-(hydroxyphenyl)but-3-en-2-ones were prepared. Their carbethoxyhydrazones form the 1,2,3-thiadiazole when treated with thionyl chloride, and the corresponding semicarbazones are oxidized by selenium dioxide to 1,2,3-selenodiazoles.