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. 08, 2005
Filed:
Jul. 02, 2004
Bobba Venkata Siva Kumar, Mumbai, IN;
Vishvas Dattatraya Patil, Ahmedabad, IN;
Changdev Namdev Raut, Navi Mumbai, IN;
Shekhar Bhaskar Bhirud, Navi Mumbai, IN;
Batchu Chandrasekhar, Navi Mumbai, IN;
Bobba Venkata Siva Kumar, Mumbai, IN;
Vishvas Dattatraya Patil, Ahmedabad, IN;
Changdev Namdev Raut, Navi Mumbai, IN;
Shekhar Bhaskar Bhirud, Navi Mumbai, IN;
Batchu Chandrasekhar, Navi Mumbai, IN;
Glenmark Pharmaceuticals Limited, Mumbai, IN (US);
Abstract
An improved process for the preparation of key intermediates for tazarotene, 4,4-dimethyl-6-ethynylthiochroman, is provided comprising (a) reacting 4,4-dimethyl-6-acetylthiochroman of the formulawith an acid chloride and an amido-group containing compound of the general formulawherein R is hydrogen or a hydrocarbyl of from 1 to 15 carbon atoms and Rand Rcan be the same or different and are hydrocarbyls of from 1 to 15 carbon atoms or Rand Rtogether with the nitrogen atom to which they are bonded are joined together to form a heterocyclic group, optionally containing one or more additional heterocyclic atoms, or one of Rand Rtogether with the nitrogen atom to which it bonded are joined together with the carbonyl radical to form a heterocyclic group, optionally containing one or more additional heterocyclic atoms to form a β-chloro vinyl carbonyl compound intermediate of the general formulawherein R has the aforestated meanings; and (b) reacting the β-chloro vinyl carbonyl compound intermediate with an alkali metal to provide the 4,4-dimethyl-6-ethynylthiochroman.