Process for the preparation of N-substituted cyclic imides

US5773630A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Torsten Groth · Reinbek, DE
• Karl-Erwin Piejko · Bensberg, DE
• Winfried Joentgen · Neunburg vorm Wald, DE
• Josef Kasbauer · Wermelskirchen, DE
• Bernd Alig · Rübhausen, DE
• Werner Struver · Leverkusen, DE

Key dates

• Filing date: Feb 6, 1996
• Grant date: Jun 30, 1998
• Expiry date: Feb 6, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D207/40
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

N-Substituted cyclic imides are obtained by reacting a cyclic acid anhydride with an amine in the presence of a solvent and an acid catalyst at 80.degree. to 200.degree. C. and with removal of the water formed, it being particularly advantageous to carry out this reaction in the presence of a stabilizer and an inert, dipolar aprotic cosolvent, optionally to add an inert organic solvent of low or zero polarity to the reaction mixture present after the reaction, to add a non-aqueous base in an amount of 0.5 to 50% by weight, based on the cyclic anhydride of the formula (II) used, and to separate off the precipitate formed to give a filtrate containing the N-substituted cyclic imide.