Imidazole → (3-Cyano-cyclohexyl)-carbamic acid tert-butyl ester

Participants

Reaction Steps

To a mixture of phosphorus oxychloride (4.60 g, 30.0 mmol) and imidazole (1.22 g, 18.0 mmol) in pyridine (40 mL) cooled in an ice-methanol bath was slowly added (3-carbamoyl-cyclohexyl)-carbamic acid tert-butyl ester (1.45 g, 6.00 mmol). The reaction was stirred for 3 hours, allowing to warm to room temperature. The suspension was filtered, the filtrate evaporated and the solids combined before partitioning between aq. NH4Cl (30 mL) and EtOAc (3×30 mL). The combined organic layers were dried (MgSO4) and evaporated to give 930 mg (69%) of (3-cyano-cyclohexyl)-carbamic acid tert-butyl ester as a gum, which was used directly in the next step. 1H NMR (400 MHz, CDCl3) δ: 4.53-4.29 (m, 1H), 3.50-3.33 (m, 1H), 2.58-2.44 (m, 1H), 2.42-2.33 (m, 1H), 2.09-1.99 (m, 1H), 1.99-1.77 (m, 3 h), 1.44 (s, 9H), 1.39-1.30 (m, 2H), 1.18-1.02 (m, 1H).

Provenance & Evidence