Glenmark Pharmaceuticals Limited

Batchu Chandrasekhar

Shekhar Bhaskar Bhirud

Bobba Venkata Siva Kumar

Vishvas Dattatraya Patil

Changdev Namdev Raut

Narendra Shriram Joshi

K Eswara Rao

Subhash Damle

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 formula with an acid chloride and an amido-group containing compound of the general formula wherein 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 &#x3b2;-chloro vinyl carbonyl compound intermediate of the general formula wherein R has the aforestated meanings; and (b) reacting the &#x3b2;-chloro vinyl carbonyl compound intermediate with an alkali metal to provide the 4,4-dimethyl-6-ethynylthiochroman.

Process for the preparation of 4,4-dimethyl-6-ethynylthiochroman

An improved process for the preparation of pyrimidine derivatives is provided comprising reacting a Wittig reagent of the general formula wherein R is an alkyl of from 1 to 10 carbon atoms, aryl or arylalkyl, Ris a substituted or unsubstituted hydrocarbon group, Rand Rare the same or different and are hydrogen or a substituted or unsubstituted hydrocarbon group; Z is sulfur, oxygen, sulfonyl, or imino which may be substituted by formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, amino substituted by sulfonyl or alkylsulfonyl, and sulfonyl substituted by alkyl, amino or alkylamino and X is a halogen; with an aldehyde of the general formula wherein Ris hydrogen, a lower alkyl or a cation capable of forming a non-toxic pharmaceutically acceptable salt and each Rare the same or different and are hydrogen or a hydrolyzable protecting group, or each R, together with the oxygen atom to which each is bonded, form a hydrolyzable cyclic protecting group, or each Ris bonded to the same substituent which is bonded to each oxygen atom to form a hydrolyzable protecting group; in the presence of a base.

Process for the preparation of pyrimidine derivatives

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 &#x3b2;-chloro vinyl carbonyl compound intermediate of the general formulawherein R has the aforestated meanings; and (b) reacting the &#x3b2;-chloro vinyl carbonyl compound intermediate with an alkali metal to provide the 4,4-dimethyl-6-ethynylthiochroman.

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Navi Mumbai, India

Batchu Chandrasekhar