Generated: May 27, 2017
|Title:||Process for preparing alkyl, aroyl substitute pyrrole-2-acetates|
|Abstract:||The compounds are of the class of 5-aroyl-pyrrole alkanoic acids and corresponding acid derivatives thereof useful as anti-inflammatory agents and as synthetic intermediates.|
|Inventor(s):||Carson; John Robert (Norristown, PA)|
|Assignee:||McNeil Laboratories, Incorporated (Fort Washington, PA)|
|Filing Date:||Jun 17, 1974|
|Claims:||1. The process of making a loweralkyl 5-aroyl-1-R.sub.4 -4-R.sub.5 -pyrrole-2-acetate of the formula: ##STR13## which comprises acylating a loweralkyl 1-R.sub.4 -4-R.sub.5 -3-loweralkoxy-carbonyl-pyrrole-2-acetate with an aroyl chloride of the formula Ar-COCl in the presence of a Lewis acid in an organic solvent suitable for Friedel-Crafts acylation reactions, hydrolyzing the thus-obtained loweralkyl 5-aroyl-1-R.sub.4 -4-R.sub.5 -3-loweralkoxycarbonyl pyrrole-2-acetate under alkaline conditions to form the corresponding alkaline salt of the di-acid, 5-aroyl-1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetic acid, separating said alkaline salt and treating same with strong mineral acid to form said di-acid, partially reesterifying said di-acid by treatment with an acidic solution of a lower alkanol and decarboxylating the 3-carboxy group of the thus-obtained loweralkyl 5-aroyl-1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetate by heating said loweralkyl 5-aroyl-1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetate to CO.sub.2 -elimination temperatures; wherein the foregoing said Ar-CO is a member selected from the group consisting of benzoyl, thenoyl, 5-methyl-thenoyl, monosubstituted benzoyl, disubstituted benzoyl and trisubstituted benzoyl, each substituent of said substituted benzoyl being a member selected from the group consisting of halo, loweralkyl, trifluoromethyl and nitro, and said R.sub.4 and said R.sub.5 each represent loweralkyl. |
2. The process of claim 1, wherein said loweralkyl 1-R.sub.4 -4-R.sub.5 -3-loweralkoxycarbonyl-pyrrole-2-acetate is ethyl 1,4-dimethyl-3-ethoxycarbonyl-pyrrole-2-acetate.