Patents by Inventor Purushotham Vemishetti

Purushotham Vemishetti 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).

  • Process for the preparation of nucleotides
    Patent number: 5591852
    Abstract: The present invention relates to a novel and economical process for the synthesis of HPMP-substituted nucleotide antiviral compounds. Also disclosed are novel intermediates produced in the process for the preparation of HPMPC.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: January 7, 1997
    Assignees: Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Rega Stichting v.z.w.
    Inventors: Purushotham Vemishetti, Paul R. Brodfuehrer, Henry G. Howell, Chester Sapino, Jr.
  • Process of preparing etoposide phosphate and etoposide
    Patent number: 5459248
    Abstract: Etoposide phosphate is prepared by coupling dibenzyl 4'-demethyl-4-epipodophyllotoxin-4'-phosphate with 2,3-di-O-benzyl-4,6-O-ethylidene-.alpha.,.beta.-D-glucopyranose in a solvent and subsequently removing the protecting groups. The tetra-benzyl protected etoposide phosphate is recrystallized from methanol or directly crystallized from acetonitrile by adding methanol to yield substantially the pure C-1"-.beta. form. The benzyl protecting groups are simultaneously removed by hydrogenation to produce etoposide phosphate in high yields. In a further embodiment, etoposide phosphate is treated with a phosphatase enzyme to yield etoposide.
    Type: Grant
    Filed: November 4, 1993
    Date of Patent: October 17, 1995
    Assignee: Bristol-Myers Squibb Company
    Inventors: Lee J. Silverberg, Purushotham Vemishetti, John L. Dillon, Jr., John J. Usher
  • N-substituted 2-azetidinones
    Patent number: 5412092
    Abstract: Novel cis compound having the formula: ##STR1## wherein R.sup.1 is alkyl, haloalkyl, cycloalkyl, aryl or a carbohydrate derivative; X is O, N, S, C(O)O or a direct bond; and R.sup.2 is aryl, substituted aryl or heteroaryl are useful in the synthesis of taxol and taxol derivatives.
    Type: Grant
    Filed: December 13, 1993
    Date of Patent: May 2, 1995
    Assignee: Bristol-Myers Squibb Company
    Inventors: Allan W. Rey, Purushotham Vemishetti, Roberto Droghini