4-[(4-fluorophenyl)amino]-1-methyl-1H-pyrazole-5-carboxylic acid → 7-FLUORO-1-METHYL-1,4-DIHYDRO-9H-PYRAZOLO[4,3-b]QUINOLIN-9-ONE

Participants

Reaction Steps

A suspension of 4-[(4-fluorophenyl)amino]-1-methyl-1H-pyrazole-5-carboxylic acid (EXAMPLE 1, step 1, 280 mg, 1.19 mmol) in phosphorus oxychloride (6 ml) was refluxed for 3 h. After cooling to room temperature, the mixture was concentrated and dried in vacuo. The residue was dissolved in 50% aqueous acetic acid (6 ml) and refluxed for 8 h. After cooling to room temperature, the mixture was diluted with ethyl acetate (200 ml), washed with saturated aqueous sodium bicarbonate (100 ml) and dried over magnesium sulfate. Removal of solvent and recrystallization from ethyl acetate gave 98 mg (38%) of the title compound as a solid.

Provenance & Evidence