反应详情

To a solution of 400 mg (1.53 mmol) of the carbinol 25 in 25 mL of dry pyridine and 20 mL of reagent grade acetone there was added 900 uL of MeNCO. The solution was magnetically stirred at room temperature in a stoppered flask until all the starting alcohol had disappeared as judged by TLC (ca. 3 days). The solvents were removed in vacuo, and the residue was crystallized from EtOAc-CH2Cl2 -MeOH to give 152 mg of the desired carbamate, mp 213°-214.5° C. The filtrate was concentrated to dryness and the remaining solid was flash chromatographed to give an additional 145 mg of material of similar purity: wt 307 mg (61%); NMR (Me2SO-d6) 11.62 (s, 1 H), 9.71 (s, 1 H), 8.46 (d, 1 H), 839 (d, 1 H), 7.97 (d, 1 H), 7.61-7.54 (m, 2 H), 7.32-7.29 (m, 1 H), 7.04 (d, 1 H), 5.77 (s, 2 H), 3.34 (s, 3 H), 2.60 (s, 3 H).

1. customas judged by TLC (ca. 3 days)
2. customThe solvents were removed in vacuo
3. customthe residue was crystallized from EtOAc-CH2Cl2 -MeOH