申请人:Beecham Group Limited
公开号:US04252976A1
公开(公告)日:1981-02-24
A process for the preparation of 3-substituted thiophenes which involves cyclization of a novel intermediate, avoids the use of previously employed expensive starting materials. The thiophenes are useful for the preparation of penicillins and cephalosporins. The process is for the preparation of a thiophene of formula (I): ##STR1## where R.sup.1 represents a carboxylic acid group, or an ester or amide thereof or a nitrile group; R.sup.2 represents a group suitable for use as an .alpha.-substituent in the side-chain of a penicillin or cephalosporin; which comprises treating a compound of formula (II): ##STR2## wherein X represents halogen or optionally functionalized hydroxyl, Y represents halogen, hydroxyl, or alkoxy; with a source of nucleophilic sulphur under basic conditions.
一种制备3-取代噻吩的方法,其中涉及新型中间体的环化,避免使用之前使用的昂贵起始材料。该噻吩对于青霉素和头孢菌素的制备非常有用。该方法是用于制备式(I)的噻吩的:##STR1## 其中R.sup.1表示羧酸基,或其酯或酰胺或腈基; R.sup.2表示适用于青霉素或头孢菌素侧链中的α-取代基的基团; 包括将式(II)的化合物进行处理:##STR2## 其中X表示卤素或可选官能团化的羟基,Y表示卤素,羟基或烷氧基; 在碱性条件下与亲核硫源反应。