反应详情

温度

-20 °C

1.87 g of 2-(5-tert.-butoxycarbonylaminomethyl-2-furyl)-acetic acid are dissolved in 200 ml of methylene chloride (distilled over phosphorus pentoxide) and 0.80 ml of 4-methylmorpholine, the solution, from which moisture is kept excluded, is cooled to -20° C. and 1.0 ml of chloroformic acid isobutyl ester is added dropwise whilst keeping the temperature at between -15° C. and -20° C. After 30 minutes, a solution of 2.31 g of 3-acetoxymethyl-7β-amino-3-cephem-4-carboxylic acid diphenylmethyl ester is added, after which the mixture is stirred for a further 2 hours at -10° C. and for 8 hours at room temperature. It is then poured out into icecold water, the pH is adjusted to 8.0 with dipotassium hydrogen phosphate and the mixture is repeatedly extracted with methylene chloride. The organic extracts are washed with a saturated aqueous sodium chloride solution and dried over magnesium sulphate, after which the solvent is removed under reduced pressure. 3-Acetoxymethyl-7β-[2-(5-tert.-butoxycarbonylaminomethyl-2-furyl)-acetylamino]-3-cephem-4-carboxylic acid diphenylmethyl ester is obtained as a colourless foam which is directly converted further; thin layer chromatogram (silica gel): Rf=0.84 (system: hexane/ethyl acetate/methanol, 20:40:40).

1. customat between -15° C. and -20° C
2. extractionthe mixture is repeatedly extracted with methylene chloride
3. washThe organic extracts are washed with a saturated aqueous sodium chloride solution
4. dry with materialdried over magnesium sulphate
5. customafter which the solvent is removed under reduced pressure