Pyrazolo-[4,3-b]- and [3,4-c]-pyridines. Reactions of 2- and 4-bromomethyl-3-nitropyridine with aromatic amines

Abstract

2-Bromomethyl-, 2-dibromomethyl-, 4-bromomethyl-, and 4-dibromomethyl-3-nitropyridine were prepared from the corresponding nitropicolines. 2-Bromomethyl-3-nitropyridine yields the expected 2-arylaminomethyl-3-nitropyridines when treated with aromatic amines at room temperature, but with higher reaction temperatures the products were 2H-pyrazolo[4,3-b]pyridines (IV). 2H-Pyrazolo[3,4-c]pyridines (VI) were similarly obtained from 4-bromomethyl-3-nitropyridine.