Acetic Anhydride → ethyl (2R,3R)-3-[(3aR,4S,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl]-3-(acetyloxy)-2-{[(benzyloxy)carbonyl]amino}propanoate

関与物質

反応手順

A solution of ethyl (2R,3R)-3-[(3aR,4R,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl]-2-{[(benzyloxy)carbonyl]amino}-3-hydroxypropanoate (3.1 g, 7.054 mmole, obtained from Reference Example 42) in acetic anhydride (25 ml) and dry pyridine (50 ml) in the presence of dimethylaminopyridine (500 mg) was stirred at room temperature under nitrogen for 15 hours. The solvent was removed in vacuo, and the residue was dissolved in ethyl acetate. The organic layer was washed with saturated sodium bicarbonate solution and saturated sodium chloride solution, dried over sodium sulfate, filtered and concentrated in vacuo. The residue was chromatographed (silica gel, methylene chloride:ether:methanol=97:2:1) to give ethyl (2R,3R)-3-[(3aR,4S,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl]-3-(acetyloxy)-2-{[(benzyloxy)carbonyl]amino}propanoate (3.4 g, 100%) as a white amorphous solid.

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