149249-72-9

The invention discloses a synthetic process of a dorzolamide Hydrochloride intermediate. According to the invention, mild zinc borohydride is adopted as a reducing agent; raw material compounds IIa 4-acetamido-5, 6-dihydro-6-methyl-4H-thieno [2, 3-b] thiopyran-2-sulfonamide-7, 7-dioxide and IIb ((4S, 6S)-4-acetamido-5, 6-dihydro-6-methyl-4H-thieno [2, 3-b] thiopyran-2-sulfonamide-7, 7-dioxide) arereduced at the temperature of 60-120 DEG C, acetamido is reduced into ethylamino, usage of a reducing agent which is highly toxic and high in operation danger coefficient is avoided, the whole reaction is easier to control, and the whole reaction process is milder and more environmentally friendly.

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.

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

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.

The present invention relates to resolution of (cis, trans) 5,6 -dihydro -4H-4-ethylamino-6-methylthieno[2,3-b] thiopyran-2-sulfonamide-7,7 -dioxide using dibenzoyl -L- tartaric acid monohydrate or di-p-toluoyl-L-tarrtaric acid monohydrate as a chiral resolving agent in presence of methanol to obtain hemitartarate salt, purifying it to obtain hemitartarate salt of 5,6-dihydro-4 H-4 (S) -ethyl amino-6(S) methylthieno [2,3-b] thiopyran-2-sulfonamide - 7,7 -dioxide with de of >99% , Chemical purity >99.5% with cis isomer content of 0.1 % and further converting into its pharmaceutically acceptable salts, preferably hydrochloride salt.

Aromatic sulfonamides with a saturated heterocycle fused thereto are carbonic anhydrase inhibitors useful in the treatment of elevated intraocular pressure.

Aromatic sulfonamides with a saturated heterocycle fused thereto are carbonic anhydrase inhibitors useful in the treatment of elevated intraocular pressure.

Aromatic sulfonamides with a saturated heterocycle fused thereto are carbonic anhydrase inhibitors useful in the treatment of elevated intraocular pressure.