反应详情

温度

0 °C

3-Cyano-4-fluoroaniline (3.7 mmol, 0.5 g) in conc. HCl (4 mL) was cooled to 0° C. and NaNO2 (4.4 mmol, 0.3 g) in water (3 mL). This was stirred at 0° C. for 30 min, then acetic acid (1.3 mL) was added. SnCl2·(H2O)2 (8.5 mmol, 1.9 g) in 1:1 water:conc. HCl (3 mL) was added dropwise to the cold solution and stirred for an additional 30 min. To this mixture 1-[4-bromophenyl]-3-hydroxy-4-acetyl-5,6-dihydropyridin-2-one (3.9 mmol, 1.2 g) was slurried in MeOH (20 mL) and added with the aid of additional MeOH (6 mL). The suspension was heated at 50° C. for 3 h, then cooled at 10° C. for 18 h. The product, 1-[3-cyano-4-fluorophenyl]-3-methyl-6-[4-bromophenyl]-1,4,5,6-tetrahydro-7H-pyrazolo[3,4-c]pyridin-7-one, was isolated by filtration. There was obtained 1.34 g (3.2 mmol) of product; mp 237.6° C., LRMS (M+H)+: 425.2/427.1 m/z.

1. stirringstirred for an additional 30 min
2. temperatureThe suspension was heated at 50° C. for 3 h
3. temperaturecooled at 10° C. for 18 h