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:
Dec. 20, 1994
Filed:
Nov. 16, 1993
Steffen Dapperheld, Hofheim am Taunus, DE;
Heinrich Volk, Bad Vilbel, DE;
Karl Peter, Rodenbach, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for the preparation of a 2-aminobenzothiazol of the formula ( I ) ##STR1## in which R.sub.1 and R.sub.2 independently of each other are hydrogen, fluorine, chlorine, bromine or iodine, trifluoromethyl or C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or nitro groups, by conversion of an arylthiourea of the formula (II) in which R.sub.1 and R.sub.2 have the meaning mentioned, which comprises carrying out the conversion in 99 to 100% strength of sulfuric acid with continuous addition of catalytic amounts of bromine, hydrogen bromide or bromide in the form of aqueous solutions and using an arylthiourea of the formula (II) which contains 1 to 35% water.