Boron trifluoride etherate → (1R*,2S*)-(E)-2-(3-(2-(pyridin-4-yl)vinyl)-1H-indazol-6-yl)spiro-[cyclo-propane-1,3'-indolin]-2'-one

Participants

Reaction Conditions

Reaction Steps

A dry-round bottom was charged with (1R*,2S*)-(E)-2-(3-(2-(pyridin-4-yl)vinyl)-1-((2-(trimethylsilyl)ethoxy) methyl)-1H-indazol-6-yl)spiro[cyclopropane-1,3′-indolin]-2′-one (320 mg, 0.62 mmol), and CH2Cl2 (15 mL) under an atmosphere of N2. Boron trifluoride etherate (1 mL) was added dropwise and the reaction was stirred for 2 h. Methylene chloride was removed in vacuo, and then 5 mL of a 2:1 mixture of EtOH/2M HCl was added and the reaction heated to 50° C. for 2 h. The reaction was cooled with an ice-bath and neutralized with NH4OH to pH˜8, the EtOH was removed and the resulting precipitate was collected. The product was purified by silica gel chromatography (85:15 CH2Cl2/MeOH) to give the title compound as a yellow solid (220 mg, 90%). 1H NMR (400 MHz, DMSO-d6) δ 13.31 (s, 1H), 10.63 (s, 1H), 8.57-8.50 (m, 2H), 8.10 (d, J=8.1 Hz, 1H), 7.80 (d, 1H, J=16.6 Hz), 7.75-7.70 (m, 2H), 7.50-7.42 (m, 2H), 7.09-6.99 (m, 2H), 6.85 (d, 1H, J=7.6 Hz), 6.53 (t, 1H, J=7.5 Hz), 6.01 (d, 1H, J=7.8 Hz) 3.23-3.19 (m, 1H), 2.35-2.31 (m, 1H), 2.02-1.98 (m, 1H); MS ESI 379.2 [M+H]+, calcd for [C24H18N4O+H]+ 379.4.

Provenance & Evidence