Acetaldehyde → Ammonia

Participants

Reaction Steps

Thetrifluoroacetic acid salt of benzyl (1S,2R,4R)-4-amino-2-(methoxymethyl)cyclohexylcarbamate (660 mg, assumed 1.68 mmol) was dissolved in methanol (5 mL) and treated with an excess of sodium cyanoborohydride (ca. 50-100 mg) and acetone (1 mL). The mixture was stirred overnight at rt, then treated with additional acetone and sodium cyanoborohydride. After 1 h, acetaldehyde (1 mL) was added, followed 4 h later by additional acetaldehyde and sodium cyanoborohydride. After stirring overnight at rt, additional acetaldehyde and sodium cyanoborohydride were added, followed by stirring for 3 days. The mixture was concentrated and the residue was dissolved in ethyl acetate and saturated aqueous NaHCO3. The layers were separated and the aqueous phase was extracted four times with ethyl acetate. The combined organic phases were dried over Na2SO4 and concentrated under vacuum. Purification by rotary preparative layer chromatography, eluting with 95:4:1 (v/v) dichloromethane:methanol:aqueous ammonia, provided benzyl (1S,2R,4R)-4-(ethyl(isopropyl)amino)-2-(methoxymethyl)cyclohexylcarbamate (430 mg). MS found: (M+H)+=363.4.

Provenance & Evidence