Patents by Inventor Ravi B. Shankar

Ravi B. Shankar 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: 5491155
    Abstract: Substituted thiadiazoles which correspond to the formula: ##STR1## wherein X and Y each independently represents --Br, --Cl, --OCH.sub.3, --SCN, --OCH.sub.2 SCN, --SCH.sub.2 SCN, --OCH.sub.2 CH.sub.2 SCN or --SCH.sub.2 CH.sub.2 SCN, provided that at least one of X or Y represents --SCN, --OCH.sub.2 SCN, --SCH.sub.2 SCN, --OCH.sub.2 CH.sub.2 SCN or --SCH.sub.2 CH.sub.2 SCN are disclosed.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: February 13, 1996
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews, Duane R. Romer
  • Patent number: 5488051
    Abstract: Substituted 5,6-dihydro-5-oxo-1,4-dithiino-(2,3-d)-pyridazine-2,3-dicarbonitriles are prepared which correspond to the formula: ##STR1## wherein R represents ##STR2## wherein X.sup.1 is Cl, Br, NO.sub.2 or CH.sub.3, y is 0 or 1 and n is 0, 1 or 2.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: April 21, 1994
    Date of Patent: January 30, 1996
    Assignee: The Dow Chemical Company
    Inventors: Duane R. Romer, R. Garth Pews, Ravi B. Shankar, Charles A. Wilson
  • Patent number: 5466707
    Abstract: Various 4,5-dimercapto-1,3-dithiolo-2-one or thione maleimides corresponding to the formula ##STR1## wherein R represents --H, phenyl, benzyl, phenethyl, a C.sub.1 -C.sub.10 straight or branched chain alkyl radical, a C.sub.3 -C.sub.10 cycloalkyl radical, a C.sub.1 -C.sub.10 straight or branched chain alkoxy radical, a C.sub.3 -C.sub.10 cycloalkoxy, an ester of the formula --CH.sub.2 CH.sub.2 O--C(O)--R.sup.1, wherein R.sup.1 represents a C.sub.1 -C.sub.5 straight or branched chain alkyl radical or a C.sub.3 -C.sub.5 cycloalkyl radical and Z represents oxygen or sulfur are disclosed.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: November 14, 1995
    Assignee: The Dow Chemical Company
    Inventors: Weishi W. Wu, Ravi B. Shankar, Duane R. Romer, R. Garth Pews
  • Patent number: 5455222
    Abstract: Disclosed are substituted-5-thiomethylthiocyanato-1H-tetrazole compounds corresponding to the formula ##STR1## wherein R represents a C.sub.1 -C.sub.6 straight or branched chain alkyl radical, a C.sub.3 -C.sub.6 cycloalkyl or a phenyl radical of the formula ##STR2## wherein each X independently represents hydrogen, halo, a C.sub.1 -C.sub.6 straight or branched chain alkyl radical, a C.sub.3 -C.sub.6 cycloalkyl radical, a C.sub.1 -C.sub.6 straight or branched chain alkoxy radical, a C.sub.3 -C.sub.6 cycloalkoxy radical, cyano or nitro and n is 0-5.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: October 3, 1995
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, Duane R. Romer, R. Garth Pews
  • Patent number: 5410065
    Abstract: 5-Acylamino-1,2,4-triazole-3-sulfonamides, which are useful intermediates for the preparation of 1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonamide herbicides are prepared from 5-amino-3-mercapto-1,2,4-triazole by sequential acylation to 5-acylamino-3-mercapto-1,2,4-triazoles, chlorination to 5-acylamino-3-chlorosulfonyl-1,2,4-triazoles, and condensation with substituted anilines to 5-acylamino-1,2,4-triazole-3-sulfonamides. 5-Acylamino-3-chlorosulfonyl-1,2,4-triazole compounds are key intermediates in the process.
    Type: Grant
    Filed: September 1, 1993
    Date of Patent: April 25, 1995
    Assignee: DowElanco
    Inventors: Jack C. Little, Mark J. Costales, Ravi B. Shankar, R. Garth Pews
  • Patent number: 5391759
    Abstract: 5-Acylamino-1,2,4-triazole-3-sulfonamides, which are useful intermediates for the preparation of 1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonamide herbicides are prepared from 5-amino-3-mercapto-1,2,4-triazole by sequential acylation to 5-acylamino-3-mercapto-1,2,4-triazoles, chlorination to 5-acylamino-3-chlorosulfonyl-1,2,4-triazoles, and condensation with substituted anilines to 5-acylamino-1,2,4-triazole-3-sulfonamides. 5-Acylamino-3-chlorosulfonyl-1,2,4-triazole compounds are key intermediates in the process.
    Type: Grant
    Filed: December 19, 1988
    Date of Patent: February 21, 1995
    Assignee: DowElanco
    Inventors: Jack C. Little, Mark J. Costales, Ravi B. Shankar, R. Garth Pews, Kidisti G. Mariam, Susan D. Thompson
  • Patent number: 5334603
    Abstract: A compound is prepared which corresponds to the formula: ##STR1## This compound has been found to exhibit antimicrobial activity in industrial and commercial applications and compositions containing this compound are so employed.
    Type: Grant
    Filed: November 16, 1993
    Date of Patent: August 2, 1994
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews, Duane R. Romer
  • Patent number: 5200409
    Abstract: Substituted 1,3-dithiolo- and 1,4-dithiinoquinoxalines are prepared which correspond to the formula: ##STR1## wherein X represents: ##STR2## and R.sup.1 and R.sup.2 independently represent hydrogen, halogen, nitro, cyano, alkyl, alkoxy, arylcarbonyl, or an alkoxy carbonyl group.These compounds have been found to exhibit antimicrobial and marine antifouling activity in industrial and commercial applications and compositions containing these compounds are so employed.
    Type: Grant
    Filed: May 22, 1992
    Date of Patent: April 6, 1993
    Assignee: The Dow Chemical Company
    Inventors: Duane R. Romer, Ravi B. Shankar, R. Garth Pews
  • Patent number: 5106407
    Abstract: The present invention discloses the antimicrobial utility of certain iodonium ylide compounds. The particular iodonium ylide compounds are phenyl iodonium ylides having an ortho substituent that stabilizes the positive charge on the polyvalent iodine by a nonbonded electrostatic interaction. The polyvalent iodine is further stabilized by a cyclic 1,3-dicarbonyl anion.
    Type: Grant
    Filed: December 4, 1989
    Date of Patent: April 21, 1992
    Assignee: The Dow Chemical Company
    Inventors: Attila G. Relenyi, Gerald F. Koser, Richard W. Walter, Jr., William J. Kruper, Jr., Ravi B. Shankar, Anthony P. Zelinko
  • Patent number: 5006656
    Abstract: 5,7-Dihydroxy-N-(aryl)-1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonamides are prepared by the cyclization of N-(3-(((aryl)amino)sulfonyl)-1H-1,2,4-triazol-5-yl)amines with malonyl halides under acidic conditions. With the addition of a phosphorus oxyhalide, malonic acid can be used in place of the malonyl halides and the 5,7-dihydroxy-1,2,4-triazolo[1,5-a]pyrimidine can be directly converted to the corresponding 5,7-dihalo derivative.
    Type: Grant
    Filed: February 26, 1990
    Date of Patent: April 9, 1991
    Assignee: DowElanco
    Inventors: Ravi B. Shankar, R. Garth Pews
  • Patent number: 4937350
    Abstract: N-(3-(((2,6-Dihalophenyl)amino)sulfonyl)-1H-1,2,4-triazol-5-yl)amines, intermediates for the preparation of herbicidal substituted 1,2,4-triazolo(1,5-a)pyrimidine-2-sulfonanilides, are directly prepared from an appropriataely substituted 4-bromoaniline and a protected 5-amino-1,2,4-triazole-3-sulfonyl chloride. The improved reaction scheme involves the individual reaction steps of (a) coupling, (b) halogenation and (c) reduction.
    Type: Grant
    Filed: June 5, 1989
    Date of Patent: June 26, 1990
    Assignee: The Dow Chemical Company
    Inventors: Ravi B. Shankar, R. Garth Pews