反应详情

Benzofuran-5-sulfonyl chloride 148 mg (0.68 mmol) was dissolved in 5 mL of methylene chloride. (1-Benzyl-2-hydroxy-3-isobutylamino-propyl)-carbamic acid hexahydro-furo[2,3-b]furan-3-yl ester 19 (244 mg, 0.62 mmol) was added followed by 0.63 mL 10% NaHCO3 solution (0.75 mmol). The reaction was stirred at room temperature for 16 hours. The organic phase was separated and loaded onto silica gel in methylene chloride. The excess of benzofuran-5-sulfonyl chloride was washed out by several portions of methylene chloride. The final product was obtained by eluting with 3/1 ethyl acetate/methylene chloride. Concentration in vacuo afforded 350 mg (98.5% yield) of the final product with HPLC purity of >97% (220 nm). The product can be recrystallized from ethyl acetate/hexanes to get colorless crystals m.p. 122-124° C. MS 573 (MH)+.

1. customThe organic phase was separated
2. washThe excess of benzofuran-5-sulfonyl chloride was washed out by several portions of methylene chloride