PROCESS FOR PRODUCING 4-ALKOXY-2/5H/-THIOPHENONE DERIVATIVES

• Main Author: MEUL,THOMAS,CH
• Format: Patent
• Language: English
• Published: 30.10.1989
• Edition: 4
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMISTRY; GENERAL METHODS OF ORGANIC CHEMISTRY; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY

1. Claims for the Contracting States : BE, CH, DE, AT, FR, GB, IT, LI, lU, NL, SE Process for the preparation of 4-alkoxy-2(5H)-thiophenones of the formula : see diagramm : EP0261668,P7,F1 wherein R1 is a straight or branched-chain alkyl group having 1 to 4 carbon atoms, characterized in that a 3-alkoxy-4-halo-2E-butenoic acid alkyl ester of the formula see diagramm : EP0261668,P7,F2 wherein R1 and R2 each are a straight or branched-chain alkyl group having 1 to 4 carbon atoms and Hal is chlorine or bromine, is either reacted with an alkali salt of thioacetic acid into a 3-alkoxy-4-thioacetoxy- 2E-butenoic acid alkyl ester, the latter is isolated and further transformed into the end product by means of an alkali hydroxide, or directly reacted to the end product with an alkali hydrogen sulfide. 1. Claims for the Contracting State : ES Process for the preparation of 4-alkoxy-2(5H)-thiophenones of the formula : see diagramm : EP0261668,P8,F1 wherein R1 is a straight or branched-chain alkyl group having 1 to 4 carbon atoms, characterized in that a 3-alkoxy-4-halo-2E-butenoic acid alkyl ester of the formula see diagramm : EP0261668,P8,F2 wherein R1 and R2 each are a straight or branched-chain alkyl group having 1 to 4 carbon atoms and Hal is chlorine or bromine, is either reacted with an alkali salt of thioacetic acid into a 3-alkoxy-4-thioacetoxy- 2E-butenoic acid alkyl ester, the latter is isolated and further transformed into the end product by means of an alkali hydroxide, or directly reacted to the end product with an alkali hydrogen sulfide.