Unexpected products from the reaction of different compounds with hydrazine hydrate or aryl thiosemicarbazides

الملخص EN

The reaction of 2,5-dihydroxyacetophenone I or 1-(1,4-dihydroxynaphthalen-2-yl)ethanone II with various 4-aryl thiosemicarbazides did not yield the expected 4-aryl-1-[1-(2,5-dihydroxyphenyl) ethylidene]thiosemicarbazides III nor 4-aryl-1-[1-(1,4-dihydroxy-naphthalen-2-yl)ethylidene] thiosemicarbazides IV, respectively.

However, unexpected products were formed namely, N1, N2-bis[1-(2,5-dihydroxyphenyl)ethylidene]hydrazine V or N1,N2-bis[1-(1,4-dihydroxynaphthalen-2- yl)ethylidene]hydrazine VI, respectively.

Also, an unexpected product N1,N2-bis(2,5-dimethoxybenzylidene) hydrazine XI was obtained when heating under reflux diethyl 2-(2,5-dimethoxybenzylidene) propanedioate VII or ethyl 2-cyano-3-(2,5-dimethoxyphenyl)propenoate VIII with 99% hydrazine hydrate in ethanol.

The mechanisms of these reactions were proposed.