Hydrochloric Acid → 1-Methyl-2-phenyl-2,5-dihydro-4H-pyrazolo[3,4-c]quinolin-4-one

Participants

Reaction Steps

Acetyl chloride (11.0 mL, 152 mmol), acetic acid (13 mL), and phenylhydrazine (15 mL, 152 mmol) were added sequentially to a suspension of ethyl (2-methyl-1H-indol-3-yl)(oxo)acetate (17 g, 76 mmol) in ethanol (380 mL). The reaction mixture was heated at reflux for 18 hours. After cooling to ambient temperature a red solid was isolated by filtration. The solid was boiled in a 1:1 mixture of 0.5 M hydrochloric acid and methanol and filtered to provide 10.8 g of 1-methyl-2-phenyl-2,5-dihydro-4H-pyrazolo[3,4-c]quinolin-4-one as a tan solid, mp>250° C. MS (APCI) m/z 276 (M+H)+; Anal. calcd for C17H13N3O: C, 74.17; H, 4.76; N, 15.26. Found: C, 73.95; H, 4.76; N, 15.04.

Provenance & Evidence