Ca. Teleha et al., SYNTHESIS AND UNEXPECTED REACTIONS OF 2-HYDROXY-3-PYRIDINYLACETIC HYDRAZIDES - FORMATION OF 2H-PYRROLO[2,3-B]PYRIDIN-2-ONES, Journal of heterocyclic chemistry, 35(1), 1998, pp. 145-149
Treatment of 2-hydroxy-3-pyridinylacetic hydrazides under mild mesylat
ion conditions provided 2H-pyrrolo[2,3-b]pyridin-2-ones as unexpected
products. This rearrangement is believed to result from an intramolecu
lar attack of the hydrazide on a reactive pyridinium species formed un
der the reaction conditions.