Methods for preparing 5-aroyl-1,2-dihydro-3h-pyrrolo-(1,2-a)Pyrrole-1-carboxylic acids

摘要

This invention pertains to methods for preparing 5-aroyl-1,2-dihydro-3H-pyrrolo-[1,2-a]pyrrole-1-carboxylic acids represented by formula <Bold>(I)</Bold>:
<Chemistry id="chema01" num="0001"><Image id="ia01" he="33" wi="54" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" /></Chemistry> The acids have useful analgesic, anti flammatory and antipyretic properties.

In a first embodiment, the method comprises the sequential steps of cyclizing, via a free radical ring closure reaction, and hydrolyzing a compound represented by formula <Bold>(IV)</Bold>:
<Chemistry id="chema02" num="0002"><Image id="ia02" he="35" wi="61" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" /></Chemistry> wherein R<Sub>1</Sub> is lower alkyl containing from 1-4 carbon atoms.

In a second embodiment, the method comprises the sequential steps of hydrolyzing and decarboxylating a compound represented by formula <Bold>(VIII)</Bold>:
<Chemistry id="chema03" num="0003"><Image id="ia03" he="45" wi="69" file="IMGA0003.TIF" imgContent="chem" imgFormat="TIFF" /></Chemistry>