Sodium Carbonate → HCID 67853110, compound

Participants

Reaction Steps

To a solution of the title product of Example 6 (640 mg, 3.76 mmol) in acetone/water (6.3 ml and 2.2 ml, respectively), a solution of benzylchloroformate (0.61 ml, 729 mg, 4.27 mmol) in acetone (2.0 ml) was added dropwise over several minutes while maintaining the pH of the mixture at 9.5 by intermittent dropwise addition of saturated aqueous sodium carbonate. After completing the addition, the reaction was stirred for 5 minutes at ambient temperature. The acetone solvent was removed in vacuo, ethyl acetate (60 ml) and water (30 ml) were added, and the pH of the well-stirred mixture was adjusted to 9.5 (sodium carbonate). The separated organic phase was dried (anhydrous sodium sulfate) and concentrated in vacuo to an oil (940 mg). Flash chromatography of the entire sample [10 g, silica gel, 32-63 mesh, eluting initially with ethyl acetate (100 mg), followed by ethyl acetate/methanol (100 ml, 97:3 in volume) and finally ethyl acetate/methanol (200 ml, 90:10 in volume)] afforded the present title compound as a colorless oil, 350 mg (30.6% yield). TLC Rf (ethyl acetate/methanol/concentrated aqueous ammonia=9:2:0.2 in volume): 0.63.

Provenance & Evidence