| 摘要 |
<p>NEW MATERIAL:A compound shown by the formula I (R1 is phenyl which may be replaced with halogen, nitro, CF3, etc.; R2 and R3 are alkoxycarbonyl, alkoxyalkoxycarbonyl, etc.; R4 is alkyl which may be replaced with cyano, OH, lower alkoxy-imino, etc.; R5 is alkyl). EXAMPLE:2-Methyl-4-( 2-chloro-5-nitrophenyl )-6-formyl-1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester. USE:A vasodilator and a hypotensor. PREPARATION:A compound shown by the formula II (R4a is alkyl which is replaced with oxo protected as acetal) is hydrolyzed to give a compound wherein R4 in the formula I is alkyl replaced with oxo. The hydrolysis is carried out usually under acidic conditions in a solvent usually under cooling.</p> |
