Abnormal ring closure and oxidation <i>in situ</i> of 2‐hydroxy‐5‐nitrobenzaldehyde in the hantzsch synthesis

Abstract

Abstract The Hantzsch condensation of 2‐hydroxy‐5‐nitrobenzaldehyde, ethyl acetoacetate and ammonia gave the hitherto unknown 2‐methyl‐3‐ethoxycarbonyl‐4‐ethoxycarbonylmethyl‐6‐(2‐hydroxy‐5‐nitrophenyl)‐pyridine via an unusual condensation and oxidation in situ.