Process for the preparation of 2-aminobenzothiazoles

US5374737A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Steffen Dapperheld · Hofheim, DE
• Heinrich Volk · Beerfelden, DE
• Karl Peter · Bochum, DE

Key dates

• Filing date: Nov 16, 1993
• Grant date: Dec 20, 1994
• Expiry date: Nov 16, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D277/82
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.