Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2005-11-08
2005-11-08
Lambkin, Deborah C. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06963002
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 R1and R2can be the same or different and are hydrocarbyls of from 1 to 15 carbon atoms or R1and R2together 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 R1and R2together 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.
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Bhirud Shekhar Bhaskar
Chandrasekhar Batchu
Kumar Bobba Venkata Siva
Patil Vishvas Dattatraya
Raut Changdev Namdev
Carmen, Esq. Michael E.
Glenmark Pharmaceuticals Limited
Lambkin Deborah C.
Williams, Esq. Corey M.
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