Ammonium Hydroxide → benzyl N-(2-methyl-5,6-dihydro-4H-imidazo[1,2-a][1]benzazepin-4-yl)carbamate

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Reaction Steps

Combine benzyl N-[(3R)-1-acetonyl-2-oxo-4,5-dihydro-3H-1-benzazepin-3-yl]carbamate (0.7 g, 1.91 mmol) with ammonium acetate (2.94 g, 38.2 mmol) in acetic acid (20.0 mL) and heat at 115° C. for 24 hours, and then stir the mixture at ambient temperature for approximately 16 hours. Pour the reaction mixture into ice-water, basify it with ammonium hydroxide (28-30%), and extract with dichloromethane. Wash with water and brine, dry over sodium sulfate, and concentrate the organic layer under reduced pressure. Purify the residue by flash chromatography (10% ethyl acetate/hexane to 50% ethyl acetate/hexane), then an SCX column (methanol, then 10% 2N ammonia in methanol/CH2Cl2) to give the title compound (0.21 g, 32%) as a white solid: MS (m/z): 348 (M+1). (Based on the final compounds made from this intermediate, the title compound is partially racemized.)

Provenance & Evidence