COC(C)(C)C.CCCCCC.[CH2:13]([O:20][C:21]([NH:23][C:24]1([C:31]([O:33][CH2:34][CH3:35])=[O:32])[CH2:29][C:28](=[O:30])[NH:27][C:25]1=[O:26])=[O:22])[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1>P([O-])([O-])([O-])=O.O1CCCC1>[CH2:13]([O:20][C:21]([NH:23][C@:24]1([C:31]([O:33][CH2:34][CH3:35])=[O:32])[CH2:29][C:28](=[O:30])[NH:27][C:25]1=[O:26])=[O:22])[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=10.5 g of esterase (PLE (21 kU/g); manufactured by Sigma-Aldrich Corporation, lyophilized powder) were dissolved in 200 mL of 0.07 mol/L phosphate buffer solution of which pH value was adjusted to 6-5 and thereto, a solution in which 10 g of 2-benzyloxycarbonylamino-2-ethoxycarbonyl succinimide were dissolved in 20 g of tetrahydrofuran was added. The resultant mixture was stirred at 30° C. for 48 hours and thereto, 100 mL of t-butyl methyl ether were added. Thereafter, the resultant mixture was filtered with Celite (No. 545) and washed with 50 mL of t-butyl methyl ether. After the filtrate was removed, the organic phase was washed with 100 ml, of water several times and the solvent was distilled off under reduced pressure. Thereafter, the product was recrystallized in ethyl acetate and hexane to thereby obtaining 3.6 g (yield: 36%) of (R)-2-benzyloxycarbonylamino-2-ethoxycarbonyl succinimide having an optical purity of 98.9% e.e. (enantiomeric excess) as a white crystal.
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