[CH3:1][C:2]1([CH3:16])[C@@H:4](/[CH:5]=[C:6](/[F:12])\[C:7]([O:9][CH2:10][CH3:11])=[O:8])[C@H:3]1[C:13]([OH:15])=[O:14].OCN1[C:23](=O)[C:22]([CH3:25])=C(C)C1=O.C([N:30](CC)CC)C.C(O)(=O)C[C:37]([CH2:42][C:43]([OH:45])=O)([C:39]([OH:41])=O)O>ClCCl.CN(C)C1C=CN=CC=1>[CH3:16][C:2]1([CH3:1])[C@@H:4](/[CH:5]=[C:6](/[F:12])\[C:7]([O:9][CH2:10][CH3:11])=[O:8])[C@H:3]1[C:13]([O:15][C:22]([CH3:23])([CH3:25])[N:30]1[C:39](=[O:41])[CH:37]=[CH:42][C:43]1=[O:45])=[O:14]
Three hundred milligrams of (1R, cis)-2,2-dimethyl-3(E)-[2-fluoro-2-(ethoxycarbonyl)ethenyl]-cyclopropane-1-carboxylic acid and 243 mg of N-(hydroxymethyl)dimethylmaleimide were dissolved in 4 ml of dry dichloromethane. To the resulting solution were added at room temperature 275 mg of N,N-dimethylaminopropyl-N'-ethylcarbodiimide hydrochloride (WSC), 200 μl of triethylamine and a catalytic amount of 4-dimethylaminopyridine. After stirring was continued for 12 hours at the same temperature, the reaction solution was poured into a cold aqueous dilute solution of citric acid, and extracted three times with dichloromethane. The dichloromethane layers were combined, washed with a saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was then distilled off under reduced pressure. The residue was subjected to column chromatography on silica gel [eluent, n-hexane:ethyl acetate=3:1 (V/V)] to obtain 205 mg of the desired dimethylmaleimidomethyl (1R, cis)-2,2-dimethyl-3(E)-[2-fluoro-2-(ethoxycarbonyl) ethenyl]-cyclopropane-1-carboxylate [present compound (1)] as a colorless, transparent, viscous oily product (yield, 43%).
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