Mild and Facile Cleavage of 2-Cyanoethyl Ester Using Sodium Sulfide or Tetrabutylammonium Fluoride. Synthesis of 1,4-Dihydropyridine Monocarboxylic Acids and Unsymmetrical 1,4-Dihydropyridine Dicarboxylates.
作者:Toshihisa OGAWA、Katsuo HATAYAMA、Hiroshi MAEDA、Yasuyuki KITA
DOI:10.1248/cpb.42.1579
日期:——
Several 3-(2-cyanoethyl)-1, 4-dihydropyridine carboxylates (16) were prepared in moderate to good yields by means of the Hantzsch reaction. Treatment of these carboxylates with a weak base such as sodium sulfide or tetrabutylammonium fluoride at room temperature afforded smoothly the corresponding 1, 4-dihydropyridine monocarboxylic acids (18) in good yields. The monocarboxylic acids 18n and 18o were esterified with 2-nitrooxypropanol or N-(2-hydroxyethyl)nicotinamide p-toluenesulfonic acid salt to afford the selective coronary vasodilators CD-349 (5) and CD-832 (6), respectively.
通过 Hantzsch 反应,制备出了几种 3-(2-氰乙基)-1,4-二氢吡啶羧酸盐 (16),收率从中等到良好。在室温下用弱碱(如硫化钠或四丁基氟化铵)处理这些羧酸盐,可以顺利地得到相应的 1,4-二氢吡啶单羧酸(18),收率良好。单羧酸 18n 和 18o 与 2-硝基氧丙醇或 N-(2-羟乙基)烟酰胺对甲苯磺酸盐进行酯化,分别得到选择性冠状血管扩张剂 CD-349 (5) 和 CD-832 (6)。