Patents by Inventor Gunar D. Tirzit

Gunar D. Tirzit 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).

  • 2,6-Dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid esters and method for preparing same
    Patent number: 4293700
    Abstract: 2,6-Dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid esters of the general formula: ##STR1## wherein R is a substituted alkyl or terpenyl. A method for preparing said esters comprises reacting esters of acetoacetic acid of the general formula: CH.sub.3 COCH.sub.2 COOR, wherein R is a substituted alkyl or terpenyl, with hexamethylenetetramine in the presence of ammonium acetate in ethanol at its boiling temperature; said esters of acetoacetic acid of the above general formula, hexamethylenetetramine and ammonium acetate can be used in stoichiometric proportions.
    Type: Grant
    Filed: April 3, 1980
    Date of Patent: October 6, 1981
    Inventors: Yan R. Uldrikis, Ieva E. Preisa, Gunar Y. Dubur, Aina A. Zidermane, Egils A. Biseniex, Gunar D. Tirzit