Synthesis of substituted 1,2‐benzoquinones and substituted 3‐hydroxy‐4 (1H)‐pyridinones: Application of oxidation—Michael addition in organic synthesis

Abstract

Catechol (1) and 2‐ethoxy‐2‐ethyl‐3‐hydroxy‐4(1H)‐pyridinone (4) derivatives can be oxidized to give ortho‐quinone of 1,2‐benzoquinone (2) and 2‐ethoxy‐2‐ethyl‐1,2(2H)‐pyridine 3,4‐dione (5) that subsequently dew Michael addition with nucleophiles. This reaction served a convenient route to synthesize 4,5‐disubstituted 1,2‐benzoquinones (3a‐c) and 6‐substituted‐3‐hydroxy‐4(1H)‐pyridinones (6a‐f).