Preparation of N-(D)-ribityl-2-phenylazo-4,5-dimethylaniline

US4360669A · kind A · utility

Assignee

• BASF SE

Inventors

• Wolfram Schmidt · Friedelsheim, DE
• Joachim Paust · Schifferstadt, DE
• Axel Nurrenbach · Havelsee, DE

Key dates

• Filing date: Jul 24, 1981
• Grant date: Nov 23, 1982
• Expiry date: Jul 24, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D475/14
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of N-(D)-ribityl-2-phenylazo-4,5-dimethylaniline (I), wherein PA0 1. in the case of pure or virtually pure (D)-ribose (III) PA0 (a) the latter is reacted with 3,4-dimethylnitrobenzene (IVa) or 3,4-dimethylaniline (IVb) and with hydrogen in the presence of a hydrogenation catalyst, PA0 (b) the resulting solution is reacted, in a conventional manner, with an acid phenyldiazonium salt solution (VI) and PA0 (c) the resulting product is isolated by crystallization, in a conventional manner, or PA0 2. in the case of crude ribose, ie. industrial mixtures of (D)-ribose and other sugars PA0 (a) the crude ribose is reacted with about equimolar amounts, based on III, of 3,4-dimethylaniline (IVb) and boric acid, PA0 (b) the boric acid ester of the Schiff base obtained from III and IVb is allowed to crystallize out and is separated off, PA0 (c) this ester is hydrogenated with hydrogen in the presence of a hydrogenation catalyst, PA0 (d) the solution is freed from catalyst and reacted, in a conventional manner, with an acid phenyldiazonium salt solution and PA0 (e) the resulting product I is isolated by crystallization in a conventional manner.