BECHDEFRGBNLSE0000633EUROPEAN PATENT APPLICATIONA319790613EP7830014019780712310087719770723GB1979061319791219790207197903 6C 07D 333/24 A 6C 07C 57:02 B 6C 07C 69:52 B 6C 07C 49:22 Ben2,5 -disubstituted-3-substituted methyl-penta-2,4-dienoic acid and derivatives, process for their preparation and their use in the preparation of alpha-substituted-thien-3-yl acetic acid and derivativesfrMéthyl-penta-2,4-diénoiques 2,5-disubstitués, 3-substitués et leurs dérivés, procédé pour leur préparation et leur application pour la préparation de l'acide thién-3-yl-acétique alpha-substitué et ses dérivésde2,5-Disubstituierte-3-substituierte Methyl-penta-2,4-diensäure und Derivate, Verfahren zu ihrer Herstellung und ihre Verwendung zur Herstellung von alpha-substituierter-thien-3-yl Essigsäure und DerivatenBEECHAM GROUP PLCGuest, Angela WendyTaylor, Andrew WilliamRamage, RobertBECHDEFRGBNLSE19790613197912

A process for the preparation of 3-substituted thiophenes which involves cyclisation 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): where R1 represents a carboxylic acid group, or an ester or amide thereof or a nitrile group; R2 represents a group suitable for use as an α-substituent in the side-chain of a penicillin or cephalosporin; which comprises treating a compound of formula (II): wherein X represents halogen or optionally functionalised hydroxyl, Y represents halogen, hydroxyl, or alkoxy; with a source of nucleophilic sulphur under basic conditions.