Patents by Inventor Lal Chand Vishwakarma

Lal Chand Vishwakarma 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: 5756740
    Abstract: A process for the preparation of photographic binary sensitizing dyes, which comprise two separate, nonconjugated chromophores, one of which has the capability of adsorbing to a silver halide grain surface, the other of which is substantially non-adsorbing to silver halide. The process comprises reacting two dye compounds in a solvent in the presence of a 2-halo-1-alkylpyridinium salt and a 4-dialkylaminopyridine.
    Type: Grant
    Filed: April 8, 1992
    Date of Patent: May 26, 1998
    Assignee: Eastman Kodak Company
    Inventors: Lal Chand Vishwakarma, Chin Hsin Chen
  • Patent number: 5739348
    Abstract: A method for preparing a compound of formula (III): ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, L, Z and p are as defined in the specification;said process preferably comprising either a noble metal catalyzed hydrogenation or a non-catalytic reductive ring closure of an azo dye compound of formula (IV): ##STR2## where R11 is as defined in the specification, thereby performing a reductive ring closure and selective O-deacylation in a single process step.
    Type: Grant
    Filed: October 23, 1996
    Date of Patent: April 14, 1998
    Assignee: Eastman Kodak Company
    Inventors: Lal Chand Vishwakarma, Victor LaVonne Mylroie
  • Patent number: 5675015
    Abstract: 2-(2'-Hydroxyphenyl)-2H-benzotriazoles of formula (I): ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8 and Z are defined in the specification, are prepared by catalytic hydrogenation of a suitable o-nitroazo dye compound in the presence of a PtS, Pt, Pd, Pt/Pd or other noble metal hydrogenation catalyst, in the presence of a base, an acid and a hydroxylic solvent.
    Type: Grant
    Filed: March 7, 1996
    Date of Patent: October 7, 1997
    Assignee: Eastman Kodak Company
    Inventors: Lal Chand Vishwakarma, Victor LaVonne Mylroie, Louis Francis Valente, Barry Francis Briffa
  • Patent number: 5674670
    Abstract: A photographic element comprising a light sensitive portion and an ultraviolet absorbing polymer comprising repeating units of a 2'-hydroxphenyl benzotriazole with a 5- or 6-substituent selected from halogen, cyano, carboxy or a sulfonyl, and a 4'-alkoxy group in which the alkylene portion of the alkoxy is linked, in sequence through a first optional bivalent linking group, then an oxygen, sulfur or amino group, then a second optional bivalent linking group, to the polymer chain, provided that the 3'-position is unsubsituted and the 4'-substituent does not have any --NH--, --OH or --SH substituents.
    Type: Grant
    Filed: March 18, 1996
    Date of Patent: October 7, 1997
    Assignee: Eastman Kodak Company
    Inventors: Lal Chand Vishwakarma, Hwei-Ling Yau, Tienteh Chen
  • Patent number: 5670654
    Abstract: A method for preparing a compound of formula (VII): ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and X are defined in the specification;the method comprising:protecting at least --XH on a compound of formula (IV) below to form a protected formula (IV) compound, by forming --X(PG) where PG is a group other than H which is not removed during a subsequent ring closure step: ##STR2## performing a ring closure by reacting the protected formula (IV) compound with a reducing agent to form a compound of formula (VI): ##STR3## wherein Z is H or a protecting group; deprotecting the compound of formula (VI) to form the compound of formula (VII) by replacing PG with H and, when Z is not H, also replacing Z with H.
    Type: Grant
    Filed: February 16, 1996
    Date of Patent: September 23, 1997
    Assignee: Eastman Kodak Company
    Inventor: Lal Chand Vishwakarma