Patents by Inventor Vellanki Siva Ram Prasad

Vellanki Siva Ram Prasad 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).

  • Crystalline forms of Nelfinavir mesylate
    Patent number: 8367832
    Abstract: The present invention provides novel crystalline forms of Nelfinavir mesylate, Form-A, Form-B, Form-C, Form-D and the process for their preparation without the use of any special equipment such as a spray drier, avoiding the use of highly flammable solvents such as ethers. The crystalline form can be tailored with the selection of the ante solvent and appropriate conditions for the process.
    Type: Grant
    Filed: August 23, 2004
    Date of Patent: February 5, 2013
    Assignee: Mylan Laboratories Limited
    Inventors: Chava Satyanarayana, Vasireddy Umamaheswara-Rao, Vellanki Siva Ram Prasad, Balusu Rajababu
  • Preparation of Zopiclone and its enantiomerically enriched isomer
    Patent number: 8309723
    Abstract: Present invention relates to an improved process for the preparation of Zopiclone and its enantiomerically enriched isomer (Eszopiclone). 6-(5-Chloropyridin-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]pyrazine is reacted with 1-chloro-carbonyl-4-methylpiperazine in the presence of alkali earth metal carbonates, hydroxides or oxides in a solvent medium to give Zopiclone. It is reacted with optically active acid in a mixture of water and water miscible organic solvent followed by work up to give Eszopiclone. The present invention also relates to process for the conversion of (R) or (S) Zopiclone to 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydro-pyrrolo-[3,4-b]-pyrazine of the intermediate which can be converted to racemic Zopiclone.
    Type: Grant
    Filed: April 10, 2008
    Date of Patent: November 13, 2012
    Assignee: Mylan Laboratories Ltd.
    Inventors: Om Dutt Tyagi, Tushar Kumar Srivastava, Vellanki Siva Ram Prasad, Dnyandev Ragho Rane, Bandi Naga Durga Rao, Daggula Srinivas Reddy
  • Preparation Of Zopiclone And Its Enantiomerically Enriched Isomer
    Publication number: 20100056785
    Abstract: Present invention relates to an improved process for the preparation of Zopiclone and its enantiomerically enriched isomer (Eszopiclone). 6-(5-Chloropyridin-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]pyrazine is reacted with 1-chloro-carbonyl-4-methylpiperazine in the presence of alkali earth metal carbonates, hydroxides or oxides in a solvent medium to give Zopiclone. It is reacted with optically active acid in a mixture of water and water miscible organic solvent followed by work up to give Eszopiclone. The present invention also relates to process for the conversion of (R) or (S) Zopiclone to 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydro-pyrrolo-[3,4-b]-pyrazine of the intermediate which can be converted to racemic Zopiclone.
    Type: Application
    Filed: April 10, 2008
    Publication date: March 4, 2010
    Inventors: Om Dutt Tyagi, Tushar Kumar Srivastava, Vellanki Siva Ram Prasad, Dnyandev Ragho Rane, Bandi Naga Durga Rao, Daggula Srinivas Reddy
  • Novel Crystalline Forms Of Nelfinavir Mesylate
    Publication number: 20080312445
    Abstract: The present invention provides novel crystalline forms of Nelfinavir mesylate, Form-A, Form-B, Form-C, Form-D and the process for their preparation without the use of any special equipment such as a spray drier, avoiding the use of highly flammable solvents such as ethers. The crystalline form can be tailored with the selection of the ante solvent and appropriate conditions for the process.
    Type: Application
    Filed: August 23, 2004
    Publication date: December 18, 2008
    Inventors: Chava Satyanarayana, Vasireddy Umamaheswara-Rao, Vellanki Siva Ram Prasad, Balusu Rajababu