Patents by Inventor Wijitha De Silva

Wijitha De Silva 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: 4365991
    Abstract: Propionic acid oximes of the general formula ##STR1## wherein R.sub.1 is hydrogen, alkyl of from 1 to 6 carbon atoms or cycloalkyl of from 3 to 6 carbon atoms, R.sub.2 is hydrogen, alkyl of from 1 to 6 carbon atoms, alkenyl of from 2 to 6 carbon atoms or alkynyl of from 2 to 6 carbon atoms, or R.sub.1 and R.sub.2 together with the carbon atom to which they are attached form a cyclopentane or cyclohexane ring which can be mono-, di- or trisubstituted with alkyl of from 1 to 3 carbon atoms, R.sub.3 is hydrogen, halogen or nitro with the proviso that R.sub.1 and R.sub.2 are not simultaneously hydrogen, processes for their manufacture, herbicidal compositions containing these compounds as the active ingredient and methods of use of the herbicidal compositions are disclosed.
    Type: Grant
    Filed: March 6, 1981
    Date of Patent: December 28, 1982
    Assignee: Hoffmann-La Roche Inc.
    Inventor: Wijitha de Silva
  • Patent number: 4098598
    Abstract: Compounds represented by the formula ##STR1## wherein R.sub.1 and R.sub.2 each are hydrogen or a phenyl; R.sub.3 is cyano; R.sub.5 OCO- in which R.sub.5 is a lower alkyl having 1-8 carbons, cycloalkyl having 3-6 carbons, alkenyl having 2-8 carbons, alkynyl having 2-8 carbons or phenyl; R.sub.6 SO.sub.2 - in which R.sub.6 is a lower alkyl having 1-8 carbons, cycloalkyl having 3 to 6 carbons or phenyl; (R.sub.7)(R.sub.8)NCO-- in which R.sub.7 and R.sub.8 each are hydrogen or a lower alkyl having 1-4 carbons, cycloalkyl having 3-6 carbons, alkenyl having 2-4 carbons or phenyl, or R.sub.7 and R.sub.8 together with the nitrogen atom to which they are attached are a 3-7 membered ring which may contain a further hetero atom; or R.sub.9 CO-- in which R.sub.9 is a lower alkyl having 1-4 carbons, cycloalkyl having 3 to 6 carbons or phenyl; and R.sub.
    Type: Grant
    Filed: January 10, 1977
    Date of Patent: July 4, 1978
    Assignee: Hoffmann-La Roche Inc.
    Inventors: Pierre Bocion, Wijitha DE Silva, Pavol Winternitz
  • Patent number: 4028089
    Abstract: Compounds represented by the formula ##STR1## wherein R.sub.1 and R.sub.2 each are hydrogen or a phenyl; R.sub.3 is cyano; R.sub.5 OCO- in which R.sub.5 is a lower alkyl having 1-8 carbons, cycloalkyl having 3-6 carbons, alkenyl having 2-8 carbons, alkynyl having 2-8 carbons or phenyl; R.sub.6 SO.sub.2 - in which R.sub.6 is a lower alkyl having 1-8 carbons, cycloalkyl having 3 to 6 carbons or phenyl; (R.sub.7)(R.sub.8)NCO- in which R.sub.7 and R.sub.8 each are hydrogen or a lower alkyl having 1-4 carbons, cycloalkyl having 3-6 carbons, alkenyl having 2-4 carbons or phenyl, or R.sub.7 and R.sub.8 together with the nitrogen atom to which they are attached are a 3-7 membered ring which may contain a further hetero atom; or R.sub.9 CO- in which R.sub.9 is a lower alkyl having 1-4 carbons, cycloalkyl having 3 to 6 carbons or phenyl; and R.sub.
    Type: Grant
    Filed: March 17, 1975
    Date of Patent: June 7, 1977
    Assignee: Hoffmann-La Roche Inc.
    Inventors: Pierre Bocion, Wijitha De Silva, Pavol Winternitz
  • Patent number: 4014678
    Abstract: Compounds represented by the formula ##STR1## wherein R.sub.1 is lower alkyl having 1-4 carbons, lower alkenyl having 2-4 carbons or lower alkynyl having 2-4 carbons; R.sub.2, R.sub.3 and R.sub.4 each are a lower alkyl having 1-4 carbons or R.sub.2 and R.sub.4 together with the carbon to which they are attached are a 5 or 6 membered alicyclic ring; and X is chlorine, bromine or iodine;Their use as plant growth regulants and plant growth regulant compositions containing the active compounds are disclosed.
    Type: Grant
    Filed: December 9, 1974
    Date of Patent: March 29, 1977
    Assignee: Hoffmann-La Roche Inc.
    Inventors: Gerhard Huppi, Wijitha De Silva, Gottlieb Ryser