| abstract |
A process for preparing (R)-5-[2-(4-fluorophenyl)-5-(1-methylethyl)-3-phenyl-4[(phenylamino)carbonyl]-1H-pyrrol-1-yl]-5-hydroxy-3-oxo-l-heptanoic acid, tert-butylester comprising: (a) reduction of 5-[2-(4-fluorophenyl)-5-(1-methylethyl)-3-phenyl-4[(phenylamino)carbonyl]-1H-pyrrol-l-yl]-3-oxo-l-pentanoic acid, (R)-2-hydroxy1,2,2-triphenylethyl ester; (b) hydrolysis of (R)-5-[2-(4-fluorophenyl)-5-(1-methylethyl)-3-phenyl-4[(phenylamino)carbonyl]-1H-pyrrol-1-yl]-3-hydroxy-l-pentanoic acid, (R)-2hydroxy-1,2,2-triphenylethyl ester using an alkali base in a solvent to form the acid; (c) alkylation of the acid forming (R)-5-[2-(4-fluorophenyl)-5-(1-methylethyl)-3phenyl-4-[(phenylamino)carbonyl]-1 H-pyrrol-1-yl]-5-hydroxy-3-oxo- l -heptanoic acid, tert-butylester. |