作者:Kunimi Inoue、Toru Sugaya、Takehiro Ogasa、Shinji Tomioka
DOI:10.1055/s-1997-1503
日期:1997.1
5-Amino-5,11-dihydro[1]benzoxepino[3,4-b]pyridines (1) show antiulcer and antiarrhythmic activity. An efficient method for the preparation of a key intermediate, furo[3,4-b]pyridin-5(7 H)-one (4), and the facile synthesis of 1 were described. The reduction of quinolinic anhydride (5) with sodium borohydride in the presence of acetic acid regioselectively gave the lactone 4. Lactone 4 was then reacted with substituted phenols under basic conditions and the resultant products, 2-(phenoxymethyl)-3-pyridinecarboxylic acids (3), underwent Friedel-Crafts cyclizations to produce the 5,11-dihydro[1]benzoxepino[3,4-b]pyridin-5-ones (2). Compounds 2 were then converted to imines with amines and successively reduced with zinc in acetic acid to the desired compounds 1.
5-氨基-5,11-二氢[1]苯并氧杂卓[3,4-b]吡啶(1)具有抗溃疡和抗心律失常的活性。本研究介绍了制备关键中间体呋喃并[3,4-b]吡啶-5(7 H)-酮(4)的有效方法以及 1 的简单合成。在乙酸存在下,用硼氢化钠还原喹啉酸酐(5),可选择性地得到内酯 4。内酯 4 随后在碱性条件下与取代的苯酚反应,生成物 2-(苯氧基甲基)-3-吡啶甲酸(3)经过弗里德尔-卡夫斯环化反应生成 5,11-二氢[1]苯并氧杂卓[3,4-b]吡啶-5-酮(2)。然后,化合物 2 与胺一起转化成亚胺,并先后在乙酸中用锌还原成所需的化合物 1。