Patents by Inventor Zhi-Xian Wang

Zhi-Xian Wang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7365201
    Abstract: A process for the preparation of the boron difluoride chelate of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolone carboxylic acid via: (a) the reaction of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolone carboxylic acid ethyl ester with, (b) fluoroboric acid in the presence of poly(methylhydrosiloxane) or hexamethyldisiloxane.
    Type: Grant
    Filed: March 2, 2006
    Date of Patent: April 29, 2008
    Assignee: Apotex Pharmachem Inc.
    Inventors: Zhi-Xian Wang, Murali Kondamreddy, Joseph DiMartino, Bhaskar Reddy Guntoori
  • Publication number: 20070208174
    Abstract: A process for the preparation of the boron difluoride chelate of quinolone-3-carboxylic acid of formula I, where R1 is an optionally substituted C1-5 alkyl, an optionally substituted C3-6 cycloalkyl, or aryl; R2 is a C1-5 alkyl, alkoxy, amino, alkylamino, or acylamino; R3 is a hydrogen, halogen, C1-5 alkoxy, amino, alkylamino, or acylamino; or when R3 is O or S forms an optionally substituted 5-, 6- or 7-membered ring T with R1, or if the ring T is substituted, the substituent is an optionally substituted C1-5 alkyl, an optionally substituted C3-6 cycloalkyl, or aryl; X is hydrogen, chloride or fluoride; and Y is chloride or fluoride; via: (a) the reaction of quinolone-3-carboxylic acid derivative II, where R1, R2, R3, T, X, and Y are as defined above and R4 is hydrogen, optionally substituted C1-5 alkyl, optionally subsituted C3-6 cycloalkyl, alkylsilyl, aryl or arylalkyl, with: (b) fluoroboric acid or trifluoroborane in the presence of a silicon-containing compound, wherein the silicon-containin
    Type: Application
    Filed: March 2, 2006
    Publication date: September 6, 2007
    Inventors: Zhi-Xian Wang, Murali Kondamreddy, Joseph DiMartino, Bhaskar Guntoori
  • Publication number: 20070207990
    Abstract: A process for the preparation of aminoalkyl phenyl carbamate compounds of Formula I, wherein R1 and R2 independently are hydrogen or a C1-6 alkyl; R3 and R4 are the same or different and each is a C1-6 alkyl; or R3 and R4 together with the nitrogen to which they are attached form a cyclic three to eight membered ring, with or without a heteroatom like nitrogen or oxygen; R5 and R6 independently are hydrogen, linear, branched or cyclic C1-6 alkyl; or R5 and R6 together with the nitrogen to which they are attached form a cyclic three to eight membered ring, with or without a heteroatom like nitrogen or oxygen; the carbon centre designated “*” can be racemic or enantiomerically enriched in the (R)— or (S)-configuration; and pharmaceutically acceptable acid addition salts thereof.
    Type: Application
    Filed: March 2, 2006
    Publication date: September 6, 2007
    Inventors: Zhi-Xian Wang, Stephen Horne, K.S. Murthy
  • Publication number: 20070173523
    Abstract: The present invention relates to a process for producing 17-N-substituted-carbamoyl-4-aza-androst-1-en-3-ones of formula 1, including Finasteride and Dutasteride.
    Type: Application
    Filed: January 20, 2006
    Publication date: July 26, 2007
    Inventors: Zhi-Xian Wang, Alfredo Ceccarelli, Mohammed Abdul Raheem, Bhaskar Guntoori
  • Publication number: 20070105898
    Abstract: A process for the preparation of cilostazol of formula I from 6-hydroxy-3,4-dihydroquinolinone of formula II and 1-cyclohexyl-5-(4-halobutyl)-tetrazole of formula III, wherein X is a halogen atom such as Cl, Br, and I, that includes combining compounds II, III, a water-miscible organic solvent, a water-soluble base and water. The cilostazol can then be separated from the reaction mixture and dissolved in a solvent A. The resulting cilostazol solution is mixed with a solvent B to precipitate cilostazol particles of defined particle size range, milling the precipitate if desired, and filtering and drying the product.
    Type: Application
    Filed: November 9, 2005
    Publication date: May 10, 2007
    Inventors: YuanQiang Li, Zhi-Xian Wang, Stephen Horne, Bhaskar Guntoori
  • Patent number: 7196197
    Abstract: Process for the preparation of Flecainide, its pharmaceutically acceptable salts and important intermediates thereof that involves the use of the 2-halobenzoic acid and its derivatives as a starting material. The use of this process also allows for the synthesis of a novel intermediate useful in the production of Flecainide. This new process is an inexpensive and efficient process for the manufacture of these compounds.
    Type: Grant
    Filed: September 17, 2003
    Date of Patent: March 27, 2007
    Assignee: Apotex Pharmachem Inc.
    Inventors: Zhi-Xian Wang, Yuanqiang Li, Bhaskar Reddy Guntoori
  • Publication number: 20070027211
    Abstract: A process which includes the reacting of sodium perborate with N-[4-cyano-3-(trifluoromethyl)phenyl]-3-[(4-fluorophenyl)thio]-2-hydroxy-2-methylpropanamide to form bicalutamide. The process is efficient, inexpensive, environmentally friendly and produces bicalutamide in good yield.
    Type: Application
    Filed: July 26, 2006
    Publication date: February 1, 2007
    Inventors: Zhi-Xian Wang, Yuan-Qiang Li
  • Publication number: 20070010678
    Abstract: Provided is an efficient method for the preparation of 3-aryloxy-3-arylpropylamines, their optical stereoisomers, and pharmaceutically acceptable salts thereof. The process allows for the isolation of 3-aryloxy-3-arylpropylamines in high yield and purity. The present invention further relates to a process for producing fluoxetine, tomoxetine, norfluoxetine, duloxetine, nisoxetine, and their optically enriched (R)— and (S)-enantiomers.
    Type: Application
    Filed: July 8, 2005
    Publication date: January 11, 2007
    Inventors: Zhi-Xian Wang, Mohammed Raheem, Gamini Weeratunga, Bhaskar Guntoori
  • Publication number: 20050059825
    Abstract: Process for the preparation of Flecainide, its pharmaceutically acceptable salts and important intermediates thereof that involves the use of the 2-halobenzoic acid and its derivatives as a starting material. The use of this process also allows for the synthesis of a novel intermediate useful in the production of Flecainide. This new process is an inexpensive and efficient process for the manufacture of these compounds.
    Type: Application
    Filed: September 17, 2003
    Publication date: March 17, 2005
    Inventors: Zhi-Xian Wang, Yuanqiang Li, Bhaskar Guntoori
  • Patent number: 6642384
    Abstract: The present invention relates to a process for the production of (S)-1,2,3,4-tetrahydro-6,7-dialkoxy-3-isoquinolinecarboxylic acid compounds (1) and their derivatives from Levodopa (L-Dopa). The ultimately prepared compounds are used as intermediates for, but not limited to, the preparation of substituted derivatives of 1,2,3,4-tetrahydro-6,7-dialkoxy-3-isoquinolinecarboxylic acid wherein R1 is hydrogen, lower alkyl, C2-C12 acyl, or R1O together are methylenedioxy; R2 is hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, substituted aryl, aralkyl or substituted aralkyl group; and R3 is hydrogen, C2-C12 acyl group, benzyl, alkoxylcarbonyl group, or aralkoxyl carbonyl group.
    Type: Grant
    Filed: June 11, 2002
    Date of Patent: November 4, 2003
    Assignee: Brantford Chemicals Inc.
    Inventors: Zhi-Xian Wang, Stephen E. Horne
  • Patent number: 6600044
    Abstract: A process for the preparation of 1,3-oxathiolane nucleoside analogues in predominantly the cis-form, from mixture of cis-/trans-1,3-oxathiolane nucleosides or their protected derivatives thereof, comprising: (i) treatment of the cis-/trans-1,3-oxathiolane nucleosides (or protected derivatives thereof) with a pyrimidine base (or it derivatives thereof) and an acid, (ii) adding a suitable acid to the obtained cis-/trans-mixture of isomers, (iii) selective crystallization of the desired cis-isomer salt from a solvent or combination of solvents, and (iv) treatment of the predominantly cis-isomer salt with a suitable base to offer the free 1,3-oxathiolane nucleosides, and thereafter optionally repeating steps (i) to (iv) inclusive.
    Type: Grant
    Filed: June 18, 2001
    Date of Patent: July 29, 2003
    Assignee: Brantford Chemicals Inc.
    Inventors: K. S. Keshava Murthy, Gurijala V. Reddy, Zhi-xian Wang, Chandrawansha B. W. Senanayake
  • Publication number: 20030013880
    Abstract: A process for the preparation of 1,3-oxathiolane nucleoside analogues in predominantly the cis-form, from mixture of cis-/trans-1,3-oxathiolane nucleosides or their protected derivatives thereof, comprising:
    Type: Application
    Filed: June 18, 2001
    Publication date: January 16, 2003
    Inventors: K.S. Keshava Murthy, Gurijala V. Reddy, Zhi-xian Wang, Chandrawansha B.W. Senanayake
  • Patent number: 6407262
    Abstract: A process for separating diastereomeric mixtures of compounds of formula 1 and formula 2 wherein R1=H or R1 denotes a carboxyl-esterifying group selected from C1-C6 alkyl and C7-C8 aralkyl, by treating the mixture of 1 and 2 with a solvent or mixture of solvents to obtain a substantially pure compound of formula 1.
    Type: Grant
    Filed: November 23, 2001
    Date of Patent: June 18, 2002
    Assignee: Brantford Chemicals Inc.
    Inventors: Zhi-Xian Wang, Cameron McPhail