公开(公告)号：US5241083A

公开(公告)日：1993-08-31

申请号：US907429

申请日：1992-07-01

申请人： Timothy Bill ,  Chris H. Senanayake ,  Robert D. Larsen ,  Sheo B. Singh ,  Thomas R. Vernhoeven

发明人： Timothy Bill ,  Chris H. Senanayake ,  Robert D. Larsen ,  Sheo B. Singh ,  Thomas R. Vernhoeven

IPC分类号： C07D493/22

CPC分类号： C07D493/22

摘要： The natural stereochemistry at the 13-position of avermectin aglycones, normally .alpha.-oriented or below the plane of the molecule, is inverted or epimerized into the .beta.-position. The procedure starts with the avermectin aglycone compounds where the 13.alpha.-hydroxy group is activated to a mesylate leaving group. The resultant 13-.alpha.-mesylate is then displaced with a cesium carboxylate and one equivalent of the respective carboxylic acid, ending with the ester group being converted to the 13-.beta.-hydroxy configuration by transesterification in high yield.

摘要翻译： 阿维菌素糖苷配基的13位天然立体化学，通常为α取向或低于分子平面，被倒置或差向异构化成β位。 该程序从其中13α-羟基被活化成甲磺酸酯离去基团的除虫菌素苷元化合物开始。 然后用羧酸铯和1当量相应的羧酸置换所得的13-α-甲酸盐，以酯基转移为最终，酯基以高产率转化为13-β-羟基构型。