Acetic Acid → HCID 20817033, compound

Participants

Reaction Steps

N-methylpiperazine (3.6 g, 0.036 mol) and acetic acid (2.17 g, 0.036 mol) were added to a suspension of 4-[4-amino-3-(4-amino-3-fluorophenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1-cyclohexanone (Intermediate R) (4.1 g, 0.012 mol) in dichloroethane (200 mL). Sodium triacetoxyborohydride (3.32 g, 0.016 mol) was then added portionwise to the reaction suspension. The reaction mixture was stirred at room temperature for 18 h. Additional sodium triacetoxyborohydride (1.79 g, 0.084 mol and 1.28 g, 0.06 mol) was added in two batches over 5 days. The reaction mixture was filtered, washed with dichloroethane (100 mL) and the filtrate was concentrated under reduced pressure to give 3-(4-amino-3-fluorophenyl)-1-[4-(4-methylpiperazino)cyclohexyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine as a yellow solid (14.5 g, 0.034 mol). The yellow solid was purified and the cis/trans isomers were separated by flash column chromatography on silica gel using dichloromethane/methanol/ammonium hydroxide (93:5:2) as the eluent to give trans 3-(4-amino-3-fluorophenyl)-1-[4-(4-methylpiperazino)cyclohexyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine (lower running component) as a white solid (115 mg, 0.27 mmol). 1H NMR (DMSO-d6, 400 MHz) 8.19 (s, 1H), 7.18 (m, 2H), 6.88 (m, 1H), 5.46 (s, 2H), 4.60 (m, 1H), 2.35 (br m, 4H), 2.14 (s, 3H), 1.95 (br m, 6H), 1.44 (m, 2H), 1.26 (m, 4H), 0.86 (m, 2H). TLC (dichloromethane/methanol/ammonium hydroxide=95:5) Rf 0.31.

Provenance & Evidence