Methylamine → tert-Butyl 4-(2-(methylcarbamoyl)benzofuran-4-yl)piperazine-1-carboxylate

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Reaction Steps

tert-Butyl 4-(2-(ethoxycarbonyl)benzofuran-4-yl)piperazine-1-carboxylate (6.17 g, 16.5 mmol) and sodium cyanide (0.081 g, 1.6 mmol) were stirred overnight at rt in methyl amine (8 M in ethanol) (62 mL, 490 mmol). The solvent was removed by rotary evaporation, the residue was dissolved in dichloromethane and transferred to a separatory funnel. The mixture was washed with 2 M sodium hydroxide and water. The organic phase was separated, dried over potassium carbonate, filtered and the solvent was removed by rotary evaporation to give the title compound. Yield: 5.8 g, 98%. The crude product was used in the subsequent step iii) without further purification. 1H NMR (500 MHz, CDCl3) δ ppm 1.51 (s, 9H) 3.06 (d, 3H) 3.15-3.23 (m, 4H) 3.61-3.70 (m, 4H) 6.59-6.66 (m, 1H) 6.71 (d, 1H) 7.13 (d, 1H) 7.29-7.35 (m, 1H) 7.51 (d, 1H).

Provenance & Evidence