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:
Dec. 05, 2006
Filed:
Dec. 03, 2002
Johannes Benkhoff, Basel, CH;
Bernd Lamatsch, Riehen, CH;
Johannes Benkhoff, Basel, CH;
Bernd Lamatsch, Riehen, CH;
Ciba Specialty Chemicals Corp., Tarrytown, NY (US);
Abstract
The present invention relates to a process for the preparation of a compound of the general formula (I), which comprises converting a compound of the general formula (II), in an aprotic organic solvent in the presence of a catalytically active amount of a strong acid (catalyst) or of an agent that liberates a strong acid or of an ammonium salt of a strong acid, it also being possible for the catalyst to be part of the starting material/product, into a compound of formula I, wherein R, Rand Rare each independently of the others a hydrogen atom, a nitro group, a sulfo group, a halogen atom, a pseudohalogen, a group COORor CONHRor a Calkyl, Calkoxy or aryloxy radical, an amide group, a thioalkyl or thioaryl radical, an alkyl- or aryl-sulfonyl radical, an alkyl- or aryl-sulfinyl radical, a trifluoromethyl group or a phosphono group, Rand Rbeing a hydrogen atom or a Calkyl radical or an aryl or aralkyl radical, Ris a group —C(O)CHC(O)CHand Ris a hydrogen atom or an acyl radical, or Rand Rare a group —C(O)CHC(O)CH. The process according to the invention is simple to perform and results in products of high chemical purity and high isomeric purity in a high yield