Pyrazolopyridines. Part III. Preparation and reactions of pyrazolo[4,3-b]pyridines

Abstract

A series of pyrazolo[4,3-b]pyridines have been prepared by nitrosation of 3-acetamido-2-methylpyridines and rearrangement and cyclisation of the N-acetyl-N-nitroso-compounds produced. The reactions of the pyrazolo[4,3-b]pyridines have been investigated. 1- and 2-Acyl compounds were obtained; their structures were elucidated by i.r. and n.m.r. spectroscopy. The ring system readily undergoes electrophilic substitution at the 3-position.