| 摘要 |
<p>Prepn. of 2-(N-benzyl-N-methylamino)-ethyl 2,6-dimethyl-4-(3-nitrophenyl)-3-methoxycarbonyl-1,4-dihydropyrid- ine-5-carboxylate of formula (I) by transesterification of dimethyl 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxyl- ate, (VII), with N-(2-hydroxyethyl)-N-methyl-benzylamine, (VIII), in a suitable solvent in the presence of a catalyst, followed by sepn. of unconverted (VII), (I) and the by-produced bis-(2-(N-benzyl-N-methylamino)ethyl) 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxyl- ate, (IX). Sepn. procedure pref. involves use of a cation exchange resin esp. crosslinked polystyrene gps. contg. sulphonic acid gps. Prod. is a vasodilator used to increase coronary and peripheral flow which is used in doses 100-3000 times higher than that of papaverine, cinnarizine etc. for the same effect. Known synthesis (BE-811324) give yields of 19 and 44% and necessitate difficult purification techniques to remove by products. The present process gives better yields, by a simple process from economic starting cpds.</p> |
