ON THE SYNTHESIS OF 3-AMINO-PYRROLES BY THORPE-ZIEGLER-CYCLIZATION

N-Aryl and alkylaminomethylene cyanacetic acid derivatives 1 react with alpha-halogencarbonyl compounds 2 in the presence of potassium carbonate/sodium ethoxide to yield the substituted 3-amino-pyrroles 6. Using the same principle of cyclization pyrrole derivatives 6 can also be obtained by reaction of beta-chloro- and beta-alkoxymethylenemalononitriles 4 with beta-aminocarbonyl compounds 5. From the malononitrile derivatives 1 containing the methylthio group in the beta-position, and alpha-halogen ketones 7, the 2-dicyanomethylene oxazolines 8 arise which undergo alkoholysis by treatment with sodium alkoxide to form the 3-amino-5-alkoxy-pyrrole derivatives 9.