Synthesis and Cyclization of 8‐Formyl‐2‐(phenoxymethyl)quinoline‐3‐carboxylic Acids

Abstract

AbstractA facile synthesis of a series of new quinoline‐8‐carbaldehyde compounds, namely 8‐formyl‐2‐(phenoxymethyl)quinoline‐3‐carboxylic acids (4a–4h) and 13‐oxo‐6,13‐dihydro[1]benzoxepino[3,4‐b]quinoline‐8‐carbaldehyde (5a–5g) is described, involving the one‐pot synthesis reaction of ethyl 2‐(chloromethyl)‐8‐formylquinoline‐3‐carboxylate (3) with substituted phenols followed by the intramolecular cyclization reaction via the treatment with polyphosphoric acid (PPA). Quinoline‐8‐carbaldehydes 4a–4h and 5a–5g are novel and their structures were supported by IR, 1H NMR, 13C NMR, MS and elemental analysis.