Ammonia → (1R,3S)-3-(Boc-amino)cyclohexanecarboxamide

참여 물질

반응 단계

Isobutylchloroformate (2.06 g, 15.0 mmol) was added dropwise with cooling in an ice-methanol bath to a solution of 3-tert-butoxycarbonylamino-cyclohexanecarboxylic acid (3.15 g, 13.0 mmol) and N-methylmorpholine (1.52 g, 15.0 mmol) in THF (40 mL). After stirring for 30 mins, methanolic ammonia (7M, 5 mL) was added. The mixture was allowed to warm to room temperature, and left to stand overnight. The residue remaining on evaporation of solvent was partitioned between aq. NH4Cl (150 mL) and DCM (150 mL). The solid suspended in the organic layer was collected, the filtrate evaporated, and the combined solids crystallised from methanol to afford 2.07 (66%) of (3-carbamoyl-cyclohexyl)-carbamic acid tert-butyl ester as colourless plates. 1H NMR (400 MHz, MeOD) δ: 6.65-6.59 (m, 1H), 3.40-3.28 (m, 1H), 2.35-2.23, (m, 1H), 2.01-1.92 (m, 1H), 1.91-1.80 (m, 2H), 1.80-1.71 (m, 1H), 1.42 (s, 9H), 1.40-1.21 (m, 3H), 1.19-1.05 (m, 1H).

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