反应详情

A solution of the methyl ester (Example 10, part ii) (1.73 g) in aqueous sodium hydroxide (2M, 5.9 ml), tetrahydrofuran (20 ml) and methanol (10 ml) was refluxed with stirring overnight. The reaction mixture was cooled, diluted with water until turbid and washed with diethyl ether (2×). The aqueous phase was acidified with acetic acid and the resulting precipitate filtered, washed with water and dried in vacuo at 50° C. to give the product as a white solid (1 g). A small amount was crystallised from tetrahydrofuran/ethanol m.p. 208°-212° C.

1. temperatureThe reaction mixture was cooled
2. washwashed with diethyl ether (2×)
3. filtrationthe resulting precipitate filtered
4. washwashed with water
5. customdried in vacuo at 50° C.