A study on ester formylhydrazones

A series of ester formylhydrazones 2 were synthesized from the reaction of alkyl imidate hydrochlorides 1 with formylhydrazine. Treatment of 2 with hydrazine hydrate, ethyl carbazate and tert ‐butyl carbazate led to the formation of 3‐alkyl‐4‐amino‐, 3‐alkyl‐4‐ethoxycarbonylamino‐ and 3‐alkyl‐4‐ tert ‐butoxycar‐bonylamino‐4 H ‐1,2,4‐triazoles 3–5 , respectively. Reaction of compounds 2 with formylhydrazine gave N,N' ‐diformylhydrazine 6 . Compounds 2 were reacted with 2,5‐dimethoxytetrahydrofuran to afford 3‐alkyl‐4‐(1 H ‐pyrrol‐1‐yl)‐4 H ‐1,2,4‐triazoles 8 .