反应详情

A solution of 0.35 g of benzyl 5-aminomethyl-3,6-dimethoxy-9,9-dimethylxanthene-4-acetate trifluoroacetate in 70 ml of acetonitrite was cooled to 0° and treated with 0.15 g of N-benzyloxycarbonyl-L-alanine. A total of 0.36 9 of O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate and 0.17 g of sodium bicarbonate were added in several portions. The reaction mixture was stirred for a total of 36 hours and thereby warmed to room temperature, whereupon it was diluted with ice-water and extracted with methylene chloride. The organic phase was washed with water, dried over magnesium sulphate and concentrated. The residue was chromatographed several times over silica gel in chloroform/methanol, whereby 0.33 g of benzyl 5-[(N-benzyloxycarbonyl-L-alanyl)aminomethyl]-3,6-dimethoxy-9,9-dimethylxanthene-4-acetate was obtained as a colourless foam; IR 1728, 1673, 1605, 1494 cm-1.

1. extractionextracted with methylene chloride
2. washThe organic phase was washed with water
3. dry with materialdried over magnesium sulphate
4. concentrationconcentrated
5. customThe residue was chromatographed several times over silica gel in chloroform/methanol