Formaldehyde → HCID 9920667, compound

Participants

Reaction Steps

A solution of 2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,7-a]indole (372 mg, 2.0 mmol) in methanol (25 mL) is treated with a solution of 37% aqueous formaldehyde (24 mmol, 2.0 mL). The resulting clear solution is treated with a single portion of sodium cyanoborohydride (251 mg, 4.0 mmol) turning slightly a lighter yellow color. After 40 min, the reaction is quenched with 1M hydrochloric acid (15 mL), stirred over 10 min, basified to pH 13, volatiles removed under reduced pressure, and extracted twice with ethyl acetate (25 mL). The combined organics are washed with brine (20 mL), dried over MgSO4, filtered, and concentrated to give a crude oil. This material is purified by LC (230-400 silica gel) eluting with 70% acetone/heptane to afford 234 mg (58%) of 3-methyl-2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,7-a]indole as a white solid, mp 59-60° C. IR (drift) 2924, 2781, 2758, 2741, 1458, 1413, 1377, 1339, 1326, 1315, 1290, 1133, 1003, 799, 737 cm−1. MS (EI) m/z 200 (M+).

Provenance & Evidence