Synthesis of Some Linear Benzochromanones

Abstract

A series of 8-substituted 6,7-benzochromanones has been prepared by cyclization of the corresponding 3-(1-X-2-naphthy1oxy)propionic acids (X = CH₃, 0CH₃, Br, NO₂) with polyphosphoric acid. Direct cyclization of the related 3-(1-X-2-naphthyloxy)propionitriles (X = CH₃, OCH₃, Br, NO₂) with sulphuric acid was successful only with X = Br, NO₂. An improved synthesis of 1-methoxy-2-naphthol is reported.