[C:1](Cl)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH3:10][O:11][C:12]([C:14]1([F:20])[CH2:18][CH2:17][CH2:16][CH:15]1[OH:19])=[O:13].Cl>N1C=CC=CC=1>[CH3:10][O:11][C:12]([C:14]1([F:20])[CH2:18][CH2:17][CH2:16][CH:15]1[O:19][C:1](=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1)=[O:13].045 g (3 mmol) of benzoyl chloride was added under ice cooling to a mixture of 0.5 g (3 mmol) of the 1-fluoro-2-hydroxy-1-cyclopentanecarboxylic acid methyl ester in cis form (compound number 2a) synthesized in Example 1 and 2 ml of pyridine, the temperature of the mixture was brought back to room temperature, and the mixture was stirred for 5 hours. The reaction solution was poured into a diluted aqueous hydrochloric acid solution and extracted with ethyl acetate and the extract was successively washed with saturated saline, a saturated aqueous sodium bicarbonate solution and saturated saline. The ethyl acetate layer was dried over anhydrous magnesium sulfate and the solvent was distilled away to obtain 0.68 g (yield: 84%) of the objective 2-benzoyloxy-1-fluoro-cyclopentanecarboxylic acid methyl ester in cis form (compound number 4a).
Wird geladen…