Novel and selective synthesis of unsymmetrieal azine derivatives via a mild reaction

摘要

A new, convenient, benign procedure for the one-step synthesis of unsymmetrieal azines by reaction of aromatic aldehyde derivatives and hydrazine sulfate in triethylamine and absolute ethanol solution is presented. This methodology is more useful than the well-known twostep variant (involving preparation of a hydrazone and subsequent reaction with an aldehyde), because it enables the formation of unsymmetrieal azines in a one-pot and rapid method without formation of any by-product or without requirement to separate the hydrazone intermediate. The mildness, selectivity, short reaction time, easy work-up, and applicability for large-scale reactions are the main advantages of this protocol for the synthesis of unsymmetrieal azine derivatives. Structures of all new compounds were elucidated by ~1H and ~(13)C NMR, IR, MS, and CHN measurements.