Process for the preparation of 4,6-diaminoresorcinol

US5574188A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Horst Behre · Odenthal, DE
• Helmut Fiege · Leverkusen, DE
• Heinz U. Blank · Odenthal, DE
• Uwe Heinz · Saarlouis, DE
• Wolfgang Eymann · Neunburg vorm Wald, DE

Key dates

• Filing date: Oct 27, 1995
• Grant date: Nov 12, 1996
• Expiry date: Oct 27, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C213/02
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

4,6-diaminoresorcinol can be prepared in a plurality of steps in such a way that a) 1,3-dichlorobenzene is nitrated with a mixed acid of HNO.sub.3, H.sub.2 SO.sub.4 and SO.sub.3 at 0 to 40.degree. C. in anhydrous H.sub.2 SO.sub.4, b) the resulting 1,3-dichloro-4,6/2,4-dinitrobenzene isomeric mixture is first reacted with benzyl alcohol in the presence of a strong base at -15.degree. C. to +15.degree. C. and then at 20.degree. to 40.degree. C. to give the dibenzyloxy compound and c) the 1,3-dibenzyloxy-4,6-dinitrobenzene isomer arising in pure form in b) is converted to the 4,6-diaminoresorcinol by catalytic hydrogenation.