The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 1992
Filed:
Dec. 20, 1990
Robert Rippel, Hofheim am Taunus, DE;
Hans-Wolfram Flemming, Usingen, DE;
Manfred Rukwied, Kelkheim, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
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.