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. 14, 1999
Filed:
May. 26, 1995
Other;
Abstract
There is disclosed a method for the preparation of pyrido benzoxazine derivative having the following formula I, that is improved in both production coat and yield. The method comprises reacting a compound of the following general formula II with tetraalkyl ammonium fluoride or with a mixture of tetraalkyl ammonium halide and metal fluoride in an organic solvent at a reaction temperature of about 30 to about 100.degree. C. for 1 to 3 hours under stirring; and reacting the resulting solution with a metal hydroxide or a metal carboxylate dissolved in water or in a mixture of water and alcohol, for 1 to 3 hours under heat. ##STR1## wherein X is a fluorine or chlorine atom and X.sub.1 and X.sub.2 each is a halogen atom or a nitro group, R is an alkyl group containing 1 to 4 carbon atoms and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each is an alkyd group or allyl group containing 1 to 8 carbon atoms.