Sodium hydride → Ethyl 1-(2,2-Diethoxyethyl)-4,5,6,7-tetrahydro-1H-indole-2-carboxylate

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Reaction Steps

To a suspension of NaH (1.44 g, 60.2 mmol) in N,N-dimethylformamide (DMF)(30 mL) was slowly added 195a (5.80 g, 30.1 mmol) at 0° C. The resulting mixture was stirred at room temperature for 0.5 h, followed by the addition of 2-bromo-1,1-diethoxyethane (11.9 g, 60.2 mmol). The reaction was heated at 70° C. for 30 h and quenched with water (100 mL). The mixture was then extracted with ethyl acetate (3×100 mL). The combined organic phase was concentrated under reduced pressure and the residue was purified with silica-gel column chromatography eluting with 40:1 petroleum ether/ethyl acetate to 195b (4.7 g, 51%). MS-ESI: [M-EtOH+H]+ 264. 1H NMR (500 MHz, DMSO-d6) δ 6.65 (s, 1H), 4.59 (t, J=5.0 Hz, 1H), 4.17-4.16 (m, 4H), 3.59-3.57 (m, 2H), 3.27-3.26 (m, 2H), 2.61 (t, J=6.0 Hz, 2H), 2.51 (t, J=6.0 Hz, 2H), 1.73-1.71 (m, 2H), 1.63-1.61 (m, 2H), 1.25 (t, J=7.0 Hz, 3H), 1.02 (t, J=7.0 Hz, 6H).

Provenance & Evidence