- PROCESS FOR PREPARING DORZOLAMIDE HYDROCHLORIDE AND ITS INTERMEDIATE
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The present invention relates to an improved process for the preparation of (4S,6S)-4- (ethylamino)-5,6-dihydro-6-methyl-4H-thieno[2,3-b]thiopyran-2-sulfonamide-7,7-dioxide hydrochloride ("Dorzolamide hydrochloride") having formula 1. Dorzolamide hydrochloride is prepared by the process of the present invention with high chemical and diastereomeric purity. The present invention also relates to novel intermediate of the formula 20 and a process for its preparation. Dorzolamide hydrochloride is useful in the treatment of ocular hypertension by inhibiting carbonic anhydrase enzyme.
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Page/Page column 19; 24-25
(2010/06/17)
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- Process for the preparation of 6-substituted-4-oxo-thieno [2,3b]thiopyran-2-sulfonic acid
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The present invention relates to one-pot process for the preparation of 6-substituted-4-oxo-thieno[2,3b]thiopyran-2-sulfonic acid of formula (I), which comprises, reacting 2-thienylthiol with alkenyl acid in the presence of an aromatic hydrocarbon solvent and a base, cyclization of the resulting compound and further reacting with an acid anhydride and sulfuric acid to get the desired compound of formula (I). The compound of formula (I) is the key intermediate in the preparation of (S,S)-5,6-dihydro-4-alkyylamino-6-substituted-4H-thieno[2,3-b]thiopyran-2-sulfonamide-7,7-dioxide and analogs thereof.
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Page/Page column 4-5
(2008/12/04)
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- Process for preparing 5,6-dihydro-4-(S)-(ethylamino)-6-(S) methyl-4H-thieno[2,3b]thiopyran-2-sulphonamide-7,7-dioxide HCI
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The present invention relates to an improved process for the preparation of 5,6-dihydro-4-(S)-(ethylamino)-6-(S)methyl-4H-thieno[2,3b]thiopyran-2-sulphonamide-7,7-dioxide hydrochloride of formula (I) commonly known as Dorzolamide Hydrochloride useful as an agent to reduce intraoccular pressure by inhibiting carbonic anhydrase enzyme
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Page/Page column 8
(2008/06/13)
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- PROCESS FOR PREPARING 5,6-DIHYDRO-4-(S)-(ETHYLAMINO)-6-(S) METHYL-4H-THIENO[2,3b]THIOPYRAN-2-SULPHONAMIDE-7,7-DIOXIDE HCI
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The present invention relates to an improved process for the preparation of 5,6-dihydro-4-(S)-(ethylamino)-6-(S)methyl-4H-thieno[2,3b]thiopyran-2-sulphonamide-7,7-dioxide hydrochloride of formula (I) commonly known as Dorzolamide Hydrochloride useful as an agent to reduce intraoccular pressure by inhibiting carbonic anhydrase enzyme.
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Page/Page column 11
(2008/06/13)
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- Process for preparing carboxylic acid derivative
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There is described a process for preparing 3-(2-thienylthio)butyric acid by converting a compound having the formula (III): STR1 wherein R is a straight chain or branched C 1 to C 4 alkyl group, whereby the production of 3-(3-thienylthio)butyric acid as a by-product which is the position isomer can be controlled to at most 0.1 mol %. 3-(2-Thienylthio)butyric acid is a useful compound as an intermediate for a medicinal compound.
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