反应详情

The resolved mono-ester of formula 18 is then deprotected by acid hydrolysis using a dilute (about 1N to about 2N) mineral acid in a suitable water-miscible solvent (preferably acetone or THF) at a temperature between about 0° and about 15° C. for about 30 to about 120 minutes. For example, (R)-1-(2-methoxyethoxy)methyl-2,6-dimethyl-3-carbomethoxy-4-(3-nitrophenyl)-5-carboxy-1,4-dihydropyridine is dissolved in CH2Cl2, treated with 1N HCl at 0° C., and allowed to stand for one hour at room temperature. Then, water (100 mL) is added, and the resulting precipitate is filtered to yield (R)-2,6-dimethyl-3-carbomethoxy-4-(3-nitrophenyl)-5-carboxy-1,4-dihydropyridine (19). (Scheme VI, Step 5)

1. filtrationthe resulting precipitate is filtered