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|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: ##SPC14## |
hydrolyzing a loweralkyl 1-R.sub.4 -4-R.sub.5 -3-loweralkoxycarbonylpyrrole-2-acetate under alkaline conditions to the di-acid, 1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetic acid,
partially re-esterifying said di-acid to loweralkyl 1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetate by treating said di-acid with an acidic solution of a lower alkanol,
decarboxylating the 3-carboxy group of said loweralkyl 1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetate to the pyrrole ester, loweralkyl 1-R.sub.4 -4-R.sub.5 -pyrrole-2-acetate, by heating said loweralkyl 1-R.sub.4 -4-R.sub.5 -3-carboxypyrrole-2-acetate to CO.sub.2 -elimination temperatures, and
acylating said loweralkyl 1-R.sub.4 -4-R.sub.5 -pyrrole-2-acetate to said loweralkyl 5-aroyl-1-R.sub.4 -4-R.sub.5 -pyrrole-2-acetate by treatment 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;
wherein the foregoing said AR--CO is a member selected from the group consisting of benzoyl, thenoyl, 5-methylthenoyl, monosubstituted benzoyl, disubstituted benzoyl and trisubstituted benzoyl, each substituent of said substituted benzoyls being a member selected from the group consisting of halo, loweralkyl, trifluoromethyl, loweralkoxy, nitro, cyano and methylthio, and said R.sub.4 and said R.sub.5 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-ethoxy carbonyl-pyrrole-2-acetate.