The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 1982
Filed:
Nov. 21, 1980
Hans Junek, Graz, AT;
Burkhard Thierrichter, Graz, AT;
Lonza Ltd., Gampel, CH;
Abstract
Process for the production of 4-amino-6-hydroxy-3-aryl isoxazolo [5,4-b] pyridine-5-carbonitriles having the formula: ##STR1## wherein R (a) is --H, (b) is --Cl or (c) is --CH.sub.3. 3-Amino-2,4,dicyanocrotonic acid methyl ester having the formula: ##STR2## is reacted with a benzohydroxyamino acid chloride having the formula: ##STR3## wherein R has the same meaning as above, in the presence of a strong base (at least molar) at a temperature of up to 10.degree. C. to produce, as an intermediate, the corresponding 3-amino-2-cyano-3-(5-amino-3-aryl-isoxazol-4-yl)-acrylic acid methyl ester having the formula ##STR4## wherein R has the same meaning as above. The intermediate product is reacted in excess diluted NaOH or KOH at a temperature of 50.degree. to 110.degree. C. to produce the corresponding 4-amino-6-hydroxy-3-aryl-isoxazolo [5,4-b] pyridine-5-carbonitrile.