反应详情

A solution of trans-4-pentylcyclohexane carboxylic acid (198 mg, 1.0 mmol) in dry toluene (1 mL) is treated with oxalyl chloride (760 mg, 5.9 mmol) at 0° C. and the mixture is stirred for 2 h at the same temperature and 1 h at room temperature. Excess reagent is removed in vacuo. A solution of the crude acid chloride in dry acetonitrile (2 mL) is added to a mixture of D-allo-Thr (100 mg, 0.85 mmol), 2N aq. NaOH (600 μl, 1.20 meq) and TEA (85 mg, 0.85 mmol) in THF (1.5 mL), following the procedure described in Example 1. The crude product 2c-6 is purified by chromatography (1.5×18 cm column, 5CH3OH and 0.4% HOAc in CH2Cl2): NMR δ 0.88 (t, J≃7, 3 H), 4.15 (m, 1 H), 4.54 (m, 1 H), 6.49 (d, 1 H); MS (CI, CH4) m/z 300 (M+H).

1. customExcess reagent is removed in vacuo
2. customis purified by chromatography (1.5×18 cm column, 5CH3OH and 0.4% HOAc in CH2Cl2)