Methyl vinyl ketone → Rac-9-(4-fluorophenyl)-3-oxo-1,2,3,5,6,7,9,12b-octahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbonitrile

Participants

Reaction Steps

A solution of 1-(4-fluorophenyl)-6-hydroxy-1,7,8,9-tetrahydrocyclohepta[f]indazole-5-carbonitrile (29, R1=4-Fluorophenyl) (30.0 g, 94 mmol) in EtOH (640 mL) was treated with TEA (3.93 mL, 28.2 mmol) and but-3-en-2-one (15.5 mL, 188 mmol) and the mixture was stirred mechanically at rt for about 18 h. The volume of the reaction was reduced to about 300 mL under reduced pressure and the intermediate was filtered off and washed with heptane (50 mL). The solid intermediate is taken up in toluene (1500 mL), treated with pTSA (0.894 g, 4.70 mmol) and heated at reflux with a Dean-Stark trap for about 5 h, then stirred at about 90° C. for about 16 h. The reaction was cooled to rt, washed with sat. aq. NaHCO3 (300 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to yield rac-9-(4-fluorophenyl)-3-oxo-1,2,3,5,6,7,9,12b-octahydrobenzo[6,7]cyclohepta[1,2-f]indazole-12b-carbonitrile (30, R1=4-Fluorophenyl) (28.0 g, 72%) as a tan foam. LC/MS, method 3, Rt=2.42 min, 1H NMR (400 MHz, DMSO) δ 8.45 (d, J=0.9 Hz, 1H), 8.20 (s, 1H), 7.84-7.78 (m, 2H), 7.69 (s, 1H), 7.48-7.39 (m, 2H), 6.18 (s, 1H), 3.01-2.59 (m, 6H), 2.46-2.37 (m, 1H), 2.24-2.12 (m, 1H), 2.02-1.87 (m, 2H).

Provenance & Evidence