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:
Oct. 07, 1980
Filed:
Jun. 19, 1979
John H Marsden, Blackley, GB;
Norman Harrison, Blackley, GB;
Imperial Chemical Industries Limited, London, GB;
Abstract
In a process for preparing the compound 4-methyl-4,5-dihydrotetrazolo [1,5-a] quinazolin-5-one having the structural formula: ##STR1## which comprises the steps of (i) bringing anthranilic acid into reaction with cyanamide at a temperature in the range of 80.degree. to 100.degree. C.; (ii) bringing the reaction product obtained by the foregoing step (i) into reaction with hydrazine hydrate in the presence of an organic solvent; then (iii) diazotizing the hydrazino compound so formed to yield a tetrazole; and finally (iv) methylating the tetrazole, the improvement which comprises using n-butanol as the organic solvent in step (ii).