Potassium Carbonate → 2-(4-aminophenyl)-1,2-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one

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Reaction Conditions

Reaction Steps

2-(4-nitrophenyl)-1,2-dihydro-3H-pyrazolo[4,3-c]cinnolin-3-one (11.4 g, 37.2 mmol) was suspended in a mixture of ethanol (100 ml) and water (100 ml). Iron powder (11.1 g, 200 mmol) and ammonium chloride (5.34 g, 100 mmol) were added. The mixture was heated to 80° C. overnight, cooled to room temperature and basified with potassium carbonate to pH 9-10. The solids were removed by filtration through a pad of Celite®. The filtrate was extracted with n-butanol (2×200 ml). The combined organic phases were concentrated under vacuum to give a dark red solid. The solid was triturated with methanol (100 ml), filtered and dried under vacuum. The title compound was isolated as a dark red powder (5.58 g, 20.1 mmol, 57%). LCMS: m/z 278 [M+H]+.

Provenance & Evidence