Preparation of 1H-pyrrol-2-acetic acid esters

US4493935A · kind A · utility

Assignee

• Rutgerswerke Aktiengesellschaft · DE

Inventors

• Winfried Orth
• Werner Fickert · Mannheim, DE

Key dates

• Filing date: Feb 2, 1984
• Grant date: Jan 15, 1985
• Expiry date: Feb 2, 2004

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D207/34
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of esters of 1H-pyrrol-2-acetic acids of the formula ##STR1## wherein R.sub.1 is selected from the group consisting of hydrogen and alkyl of 1 to 4 carbon atoms and R.sub.2 is selected from the group consisting of alkyl of 1 to 4 carbon atoms and aralkyl of 1 to 4 alkyl carbon atoms comprising reacting a compound of the formula ##STR2## wherein R.sub.3 is selected from the group consisting of --CN and ##STR3## in an aqueous media with a saponification base wherein the saponification base is added gradually to the 1H-pyrrol-2-acetonitrile and/or 1H-pyrrol-2-acetamide to selectively saponify the same to obtain a substantially isomer-free salt of 1H-pyrrol-2-acetic acid, adding alkali metal bicarbonate to the solution to keep the pH of solution at about 10.2 to 10.5 and reacting the salt of 1H-pyrrol-2-acetic acid without isolation and without removal of any water with a solution of an alkylating or aralkylating agent in an organic water-insoluble solvent in the presence of a phase transfer agent to obtain the ester of formula I in excellent yields and purity.