Investigation of keto-enol tautomers during the synthesis of aryl-bis (2-hydroxy-1-naphthyl)methanes

Abstract

This study investigated the existence of keto-enol tautomers for the first time during the synthesis of aryl-bis(2-hydroxy-1-naphthyl)methane from 2-naphthol and p-tolualdehyde or 4-chlorobenzaldehyde in methanol using CuSO4.5H2O as catalyst under reflux condition. The exclusive formation of aryl-bis(2-hydroxy-1-naphthyl)methanes was observed in dichloromethane at room temperature in the presence of BF3.OEt2/AcOH as catalyst. The keto products were isolated and characterized by 1H NMR, 13C NMR, COSY and DEPT spectra. [Figure not available: see fulltext.]