A reinvestigation of the Pictet–Gams isoquinoline synthesis. Part 1. The consequences of oxazoline rather than isoquinoline formation

Abstract

Cyclisation of various 2-acylamino-1-arylalkan-1-ols under typical Pictet–Gams conditions yields Δ²-oxazolines and not isoquinolines as previously reported. Compounds originally formulated as isoquinolines and isoquinoline hydrochlorides are shown to be derivatives of 2-amino-1-phenylalkan-1-ols, and to have arisen through ringcleavage of the Δ²-oxazolines during the isolation procedure. Their mode of formation is fully explained.