Sodium Bicarbonate → 7,8-Difluoro-1,2,3,4-tetrahydrocyclopent[b]indole

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Reaction Steps

A stirred solution of 7,8-difluoro-1,2,3,3a,4,8a-hexahydro-8a-hydroxy-cyclopent[b]indole (1.1 g, 5.2 mmol), in dichloromethane (150 mL) was cooled to 0° C. Trifluoroacetic acid (20 drops) was added and the reaction mixture was stirred at room temperature for 18 h. The reaction mixture was poured onto saturated sodium hydrogen carbonate solution (20 mL) and extracted with dichloromethane (3×50 mL). The organic extracts were combined, dried (magnesium sulfate), filtered, concentrated in vacuo and purified by column chromatography [SiO2; ethyl acetate-heptane (1:5)]to give the product (0.78 g, 78%) as a white crystalline solid. IR νmax (Nujol)/cm−1 3467, 2925, 2854, 1565, 1515, 1450, 1348, 1327, 1244, 1053, 1025, 977, 857, 783, 630 and 516; NMR δH (400 MHz, CDCl3) 2.49-2.58 (2H, m), 2.79-2.87 (2H, m), 2.9-2.96 (2H, m), 6.81-6.95 (2H, m), and 7.83 (1H), br s).

Provenance & Evidence