Stannous chloride dihydrate → 1,3-Dihydro-2H-pyrrolo[3,2-b]pyridin-2-one

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Reaction Steps

A mixture of 2-(3-nitro-2-pyridyl)ethyl acetate (10.1, 48 mmol), tin(II)chloride dihydrate (54.3 g, 240 mmol) and ethyl acetate was stirred and heated at reflux for 5 hours. The reaction mixture was allowed to cool overnight, filtered through diatomaceous earth and the solvent was removed by evaporation. The resulting oil was purified by flash chromatography using increasingly polar solvent mixtures starting with methylene chloride and ending with methylene chloride/methanol (10/1). Removal of the solvent by evaporation gave 4-azaoxindole (2.1 g, 33%).

Provenance & Evidence