A CONVENIENT SYNTHESIS METHOD OF 5-OXOPYRAZOLO[4,3-<i>b</i>]PYRIDINE-6-CARBOXYLIC ACIDS AND THEIR NITRILES

Authors

  • Георгий Г. Яковенко National University of "Kyiv-Mohyla Academy" Institute of Organic Chemistry of the NAS of Ukraine
  • Олег А. Лукьянов Институт органической химии НАН Украины
  • Андрей В. Больбут Институт органической химии НАН Украины, НПО ''Енамин''
  • Михаил В. Вовк Институт органической химии НАН Украины

DOI:

https://doi.org/10.1007/5201

Keywords:

cyanoacetic acid, 5-formyl-1H-pyrazol-4-amine, malonic acid, methyl cyanoacetate, monomethyl malonate, pyrazolo[4, 3-b]-pyridine-6-carbonitrile, 3-b]pyridine-6-carboxylic acid, cyclocondensation

Abstract

N-Boc-protected 5-formyl-1H-pyrazol-4-amines react with malonic acid in pyridine in the presence of pyrrolidine at 45–50°С or with malonic acid monomethyl ether in the presence of pyrrolidine in AcOH under reflux with the formation of 5-oxo-4,5-dihydro-1H-pyrazolo[4,3-b]pyridine-6-carboxylic acids. The reaction of N-Boc-protected 5-formyl-1H-pyrazol-4-amines with cyanoacetic acid in pyridine in the presence of pyrrolidine at 45–50°С leads to the formation of 5-oxo-4,5-dihydro-1H-pyrazolo[4,3-b]pyridine-6-carbonitriles. The latter can also be obtained via cyclocondensation of N-Boc-protected 5-formyl-1H-pyrazol-4-amines with methyl cyanoacetate in AcOH under reflux in the presence of pyrrolidine or in MeCN containing pyrrolidine and a catalytic amount of proline heated under reflux.

Published

2019-12-18

Issue

Section

Original Papers