Process for the preparation of thiophene derivatives and also new dihydrothiophene 1-oxides

US5166346A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Robert Rippel · Hofheim, DE
• Hans-Wolfram Flemming · Usingen, DE
• Manfred Rukwied · Kelkheim, DE

Key dates

• Filing date: Dec 20, 1990
• Grant date: Nov 24, 1992
• Expiry date: Dec 20, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D333/38
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for the preparation of thiophene derivatives and also new dihydrothiophene 1-oxides. Thiophene derivatives having an--optionally substituted--amino group on the thiophene ring are prepared by dehydrogenating dihydrothiophenes, substituted in a manner identical to that of the desired thiophene derivatives, by means of H.sub.2 O.sub.2, the dihydrothiophenes being reacted with H.sub.2 O.sub.2 in a first reaction stage in a neutral medium to give the corresponding sulfoxides, which are then rearranged into the thiophene derivatives by means of acid in the second reaction stage. The dihydrothiophene 1-oxides formed as intermediates in this reaction are new compounds. Like the thiophene derivatives formed from them by rearrangement with acid, they are intermediates, mainly in the sector of plant protection agents and pharmaceuticals.