反应详情

The 1-fluoro-2-hydroxy 1-cyclopentanecarboxylic acid methyl ester in cis form (compound number 2a) synthesized in Example 1 was methylated in the same manner as in Example 10 and further hydrolyzed in the same manner as in Example 11 to obtain 1-fluoro-2-methoxy-1-cyclopentanecarboxylic acid in cis form (compound number 12a). 0.4 g (2.7 mmol) of this carboxylic acid, 0.20 g (2.7 mmol) of tertiary butyl alcohol, 0.56 g (3.7 mmol) of dicyclohexylcarbodiimide and 15 mg of 4,4-dimethylaminopyridine were mixed in 5 ml of ether and stirred at room temperature for 2 hours. The reaction solution was filtered, ether was added to the filtrate, and the mixture was successively washed with a diluted hydrochloric acid solution, saturated saline, a saturated aqueous sodium bicarbonate solution and saturated saline. The ether layer was dried over anhydrous magnesium sulfate, and the solvent was distilled away to obtain 0.31 g (yield: 56%) of the objective 2-methoxy-1-fluoro-1-cyclopentanecarboxylic acid tertiary butyl ester in cis form (compound number 20a).

1. filtrationThe reaction solution was filtered
2. additionether was added to the filtrate
3. washthe mixture was successively washed with a diluted hydrochloric acid solution, saturated saline
4. dry with materialThe ether layer was dried over anhydrous magnesium sulfate
5. distillationthe solvent was distilled away