- ASYMMETRIC REDUCTION PROCESS
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The present invention relates to a stereoselective reduction procedure to obtain, by means of catalytic asymmetric hydrogenation by hydrogen transfer, a compound of formula (I) in which X is S or SO2 and R4 is hydrogen or an SO2NH2 group, from the corresponding ketone precursor, said compound of formula (I) being useful as an intermediate in the preparation of dorzolamide or of the hydrochloride salt thereof.
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Page/Page column 13; 14
(2012/09/22)
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- 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 20; 26
(2010/06/17)
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- Applying lipase catalysis to access the enantiomers of dorzolamide intermediates
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The kinetic resolution of three dorzolamide intermediates has been studied in the presence of Burkholderia cepacia li-pase in organic solvents. All the stereoisomers of 6-methyl-5,6-dihydro-4H-thieno[2,3-b]thiopyran-4-ol were prepared starting from the ra
- Turcu, Mihaela C.,Rantapaju, Maria,Kanerva, Liisa T.
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experimental part
p. 5594 - 5600
(2010/03/01)
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- Process for obtaining 4-hydroxy-6-methyl-5,6-dihydro-4H-thieno[2,3-b]thiopyran-7,7-dioxide and its enantiomers, and applications thereof
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The invention relates to a process for obtaining cis-4-hydroxy-6-methyl-5,6-dihydro-4H-thieno[2,3-b]thiopyran-7,7-dioxide, its enantiomers or mixtures thereof, by reduction of 5,6-dihydro-6-methyl-4H-thieno[2,3-b]thiopyran-4-one-7,7-dioxide with a reducing agent which generates hydride ions. The obtained compounds are useful as intermediates in the synthesis of chiral active ingredients.
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Page/Page column 12
(2009/12/23)
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- ENZYMATIC ASYMMETRIC REDUCTION PROCESS TO PRODUCE 4 H-THIENO(2,3-6)THIO PYRANE DERIVATIVES
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PCT No. PCT/GB93/01776 Sec. 371 Date Feb. 28, 1995 Sec. 102(e) Date Feb. 28, 1995 PCT Filed Aug. 20, 1993 PCT Pub. No. WO94/05802 PCT Pub. Date Mar. 17, 1994A compound of formula in which X is hydrogen or a group of formula -SO2NH2 is reduced to the trans (4S,6S) form of the corresponding alcohol by an enzyme reduction system.
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- β-Butyrolactone as a chiral building block in organic synthesis: A convenient synthesis of MK-0507 keto sulfone
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The nucleophilic ring opening of (R)-β-butyrolactone 2 with 2-thiophenethiolate is the key step in a straightforward stereospecific synthesis of keto sulfone 1, a precursor to carbonic anhydrase inhibitor MK-0507.
- Tempkin, Orin,Blacklock, Thomas J.,Burke, J. Andrew,Anastasia, Maria
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p. 2721 - 2724
(2007/10/03)
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- A Practical Process for the Preparation of Tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolooxazaborole-Borane. A Highly Enantioselective Stoichiometric and Catalytic Reducing Agent
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A practical, large-scale process for the preparation of tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolooxazaborole-borane is reported.The title compound is a stable, free-flowing crystalline solid useful either stoichiometrically or catalytically for the enantioselective reduction of prochiral ketones.When used stoichiometrically to reduce acetophenone the enantioselectivity is >= 99.8 percent ee.
- Mathre, David J.,Thompson, Andrew S.,Douglas, Alan W.,Hoogsteen, Karst,Caroll, James D.,et al.
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p. 2880 - 2888
(2007/10/02)
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