Patents by Inventor Dharmaraj Ramachandra Rao

Dharmaraj Ramachandra Rao 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: 8691999
    Abstract: An improved process for the preparation of telmisartan, or a pharmaceutically acceptable salt thereof, comprises subjecting 1H-Benzimidazole-2-n-propyl-4-methyl-6-(1?-methyl benzimidazole-2?yl)] of formula (II), and methyl-4-(bromomethyl)biphenyl-2-carboxylate of formula (III) to condensation and hydrolysis in a single step:
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: April 8, 2014
    Assignee: Cipla Limited
    Inventors: Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao, Srinivas Laxminarayan Pathi, Ravikumar Puppala
  • Patent number: 8658821
    Abstract: A one-pot process for the preparation of nateglinide, which process comprises reacting an alkyl ester of D-phenylalanine of formula (II): where R represents C1-4alkyl, typically methyl, either as the free base or in salt form (typically the hydrochloride), with trans-4-isopropylcyclohexanecarboxylic acid of formula (III): where X represents hydroxy or halo, typically chloro, to obtain a C1-4 alkyl ester of nateglinide of formula (IV), preferably the methyl ester of nateglinide: followed by hydrolysis to yield nateglinide of formula (I):
    Type: Grant
    Filed: June 8, 2005
    Date of Patent: February 25, 2014
    Assignee: Cipla Limited
    Inventors: Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao, Manjinder Singh Phull, Dilip Ramdas Birari
  • Patent number: 8642758
    Abstract: A process for the preparation of a salt of N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine comprising reacting a 4-halo-6,7-bis(2-methoxyethoxy) quinazoline with 3-aminophenyl acetylene or an acid salt thereof under acidic conditions to form the corresponding acid salt of N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine, the process optionally further comprising converting the acid salt of N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine to N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine.
    Type: Grant
    Filed: April 3, 2008
    Date of Patent: February 4, 2014
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan
  • Patent number: 8633234
    Abstract: Amorphous rifaximin, methods of making it, and pharmaceutical compositions containing it. Also described are methods of converting amorphous rifaximin to crystalline rifaximin and vice versa.
    Type: Grant
    Filed: September 24, 2007
    Date of Patent: January 21, 2014
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Manjinder Singh Phull, Maruti Ghagare
  • Patent number: 8575393
    Abstract: There is provided a process for preparing a salt of the (R)- or (S)-isomer of 1-naphthylethylamine with mandelic acid or a derivative thereof, the process comprising reacting racemic 1-naphthylethylamine with mandelic acid or a derivative thereof to obtain the (R)- or (S)-isomer of 1-naphthylethylamine salt (III) with the acid. The salts also form an aspect of the present invention. There is also provided a salt of the (R)- or (S)-isomer of 1-naphthylethylamine with mandelic acid or a derivative thereof. There is also provided a process for preparing cinacalcet (I) or a salt thereof, the process comprising reacting an ester (II) with (R)-1-naphthylethylamine or a salt of (R)-1-naphthylethylamine and mandelic acid or a derivative thereof, to obtain cinacalcet, and optionally converting the cincalcet to a salt thereof.
    Type: Grant
    Filed: March 4, 2010
    Date of Patent: November 5, 2013
    Assignee: CIPLA Limited
    Inventors: Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao, Dilip Ramdas Birari
  • Patent number: 8519126
    Abstract: Crystalline Form C of tenofovir disoproxil, salts thereof and a process for its preparation. The process involves adding a solution comprising tenofovir disoproxil and an organic solvent to salt-saturated water, whereby the crystalline Form C of tenofovir disoproxil precipitates. The crystalline Form C of tenofovir disoproxil may be converted to a salt thereof. There is also provided a process for purifying a crude product comprising tenofovir monoisoproxil and tenofovir disoproxil.
    Type: Grant
    Filed: July 30, 2008
    Date of Patent: August 27, 2013
    Assignee: Cipla Limited
    Inventors: Manjinder Singh Phull, Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao
  • Patent number: 8481730
    Abstract: The present invention relates to alkaline earth metal salts of bosentan, anyhdrous bosentan, polymorphic forms thereof, amorphous bosentan and processes for preparing them. The present invention further relates to a process for the preparation of bosentan and its pharmaceutically acceptable salts.
    Type: Grant
    Filed: January 2, 2009
    Date of Patent: July 9, 2013
    Assignee: CIPLA Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Manjinder Singh Phull, Ashwini Amol Sawant
  • Publication number: 20130165686
    Abstract: The present invention relates to a process for the preparation of substantially pure nateglinide of formula (I), substantially free from the cis-isomer and L-enantiomer and preparation of enantiomerically pure nateglinide form B, directly from the hydrolysis of a (?)-N-(trans-4-isopropylcyclohexyl-1-carbonyl)-D-phenylalanine alkyl ester in a ketonic solvent or water or mixture thereof.
    Type: Application
    Filed: June 14, 2011
    Publication date: June 27, 2013
    Applicant: CIPLA LIMITED
    Inventors: Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao, Dilip Ramdas Birari
  • Publication number: 20130150588
    Abstract: The present invention provides dexrabeprazole magnesium hydrate and a process for its preparation. The present invention also provides a magnesium, calcium or potassium salt of dexrabeprazole, optionally in amorphous form, and processes for its preparation.
    Type: Application
    Filed: June 24, 2011
    Publication date: June 13, 2013
    Applicant: CIPLA LIMITED
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Srinivas Laxminarayan Pathi, Dilip Ramdas Birari
  • Patent number: 8461334
    Abstract: The present invention provides a process for the preparation of the dextrorotatory isomer of zopiclone (eszopiclone). The present invention also provides eszopiclone di-p-anisolyl-L-tartrate and eszopiclone diacetyl-L-tartrate, which are useful as intermediates in a process for preparing eszopiclone.
    Type: Grant
    Filed: November 6, 2009
    Date of Patent: June 11, 2013
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Maruti Ganpati Ghagare, Sunilkumar Parasnath Saroj
  • Patent number: 8461388
    Abstract: A process for preparing a compound of formula (V) or its enantiomer, which comprises: (a) reacting racemic aminoindan of formula (II) or its enantiomer with allylhalide in presence of a base and an organic solvent at a temperature ranging from 25 C to the reflux temperature of the solvent to give compound of formula (III); Where R is H or (b) reacting the compound (III) with halogenating agent in a suitable organic solvent to give a dihalo compound of formula (IV). (c) treating the dihalo compound (IV) with a suitable base to give compound (V).
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: June 11, 2013
    Assignee: CIPLA Limited
    Inventors: Manjinder Singh Phull, Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan
  • Patent number: 8445687
    Abstract: There is provided a process for preparing sorafenib or a salt thereof comprising the use of a compound of formula (A) wherein R? is selected from the group consisting of hydrogen, —C(O)OA, —C(O)CX3, —C(O)NH2, —C(O)—NHOH or There is also provided intermediate compounds of general formula (A), N-methyl-4-(4-ureidophenoxy)picolinamide, 4-(2-(methylcarbamoyl)pyridin-4-yloxy)phenylcarbamate derivative and N-methyl-4-(4-(2,2,2-trihaloacetamido)phenoxy)picolinamide, processes for their preparation and their use in the preparation of sorafenib.
    Type: Grant
    Filed: September 10, 2008
    Date of Patent: May 21, 2013
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Maruti Ghagare, Sandip Chikhalikar
  • Patent number: 8426590
    Abstract: The present invention relates to a process for the preparation of doxazosin or salts thereof.
    Type: Grant
    Filed: March 23, 2010
    Date of Patent: April 23, 2013
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Dilip Ramdas Birari
  • Patent number: 8394963
    Abstract: A process for preparing Form A of (S)-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl) -methyl]sulfinyl]-1H-benzimidazole magnesium dihydrate, processes for preparing various intermediates useful in the preparation of Form A of (S)-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)-methyl]sulfinyl]-1H-benzimidazole magnesium dihydrate and a novel polymorphic Form II of 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)-methyl]thio]-1H-benzimidazole.
    Type: Grant
    Filed: February 21, 2008
    Date of Patent: March 12, 2013
    Assignee: Cipla Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Srinivas Laxminarayan Pathi, Gopalakrishna Sumana Bangalore
  • Patent number: 8383627
    Abstract: Crystalline Form IV of doxazosin mesylate, a process for its preparation and uses thereof.
    Type: Grant
    Filed: July 10, 2008
    Date of Patent: February 26, 2013
    Assignee: CIPLA Limited
    Inventors: Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao, Manish Gopaldas Gangrade, Shrikant Suresh Mudgal
  • Publication number: 20130029945
    Abstract: There is disclosed crystalline darunavir hydrate substantially free of any non-aqueous solvent.
    Type: Application
    Filed: October 6, 2010
    Publication date: January 31, 2013
    Applicant: CIPLA LIMITED
    Inventors: Manjinder Singh Phull, Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan
  • Patent number: 8349863
    Abstract: The invention relates to a novel crystalline form of topotecan hydrochloride, and methods of making the same. The characteristic XRPD pattern and FT-IT patterns are shown in FIGS. 1 and 2.
    Type: Grant
    Filed: October 10, 2006
    Date of Patent: January 8, 2013
    Assignee: Cipla Limited
    Inventors: Srinivas Laxminarayan Pathi, Shashi Rekha Kanathala, Manish Gopaldas Gangrade, Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao
  • Patent number: 8350029
    Abstract: There is provided a compound of formula III, and a process for preparing a compound of formula V comprising converting a compound of formula III to the compound V, wherein X is fluoro, chloro, bromo or iodo. There is also provided a process for preparing a compound of formula XI comprising converting a compound of formula X to the compound XI. The compounds V and XI so prepared may be used in a process for preparing gefitinib.
    Type: Grant
    Filed: April 16, 2008
    Date of Patent: January 8, 2013
    Assignee: CIPLA Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Srinivas Laxminarayan Pathi
  • Patent number: 8350031
    Abstract: The present invention provides a compound of formula (IV) wherein R is Cl, Br, NO2, OH or OR?, and R? is alkyl, and its use in the synthesis of levocetirizine, including its use in the synthesis of (?)-1-[(4-chlorophenyl)-phenylmethyl]piperazine, an intermediate useful in the synthesis of levocetirizine. The present invention also provides compounds (II) and (III) which are useful in the synthesis of compound (IV).
    Type: Grant
    Filed: June 2, 2009
    Date of Patent: January 8, 2013
    Assignee: CIPLA Limited
    Inventors: Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Maruti Ghagare, Sandip Vasant Chikhalikar
  • Patent number: RE43984
    Abstract: A process for making optically Optically pure (R) and (S) salbutamol comprises obtaining the (R) or (S) isomer of either salbutamol or a salbutamol precursor in substantially optically pure form is obtained by resolving a racemic or optically impure mixture of enantiomers of salbutamol or of said a salbutamol precursor with either (L) or (D) tartaric acid, and where necessary converting said isomer of said precursor into either (R) or (S) salbutamol respectively; then optionally converting said optically pure (R) and/or (S) salbutamol into a pharmaceutically acceptable salt.
    Type: Grant
    Filed: December 10, 2001
    Date of Patent: February 5, 2013
    Assignee: Cipla Limited
    Inventors: Yusuf Khwaja Hamied, Rajendra Narayanrao Kankan, Dharmaraj Ramachandra Rao