New Syntheses of 2,4-Diaminopyrroles and Aminopyrrolinones

Article abstract of DOI:10.1007/BF00807103

Oxazolin-2-ylidene-malononitriles 3a-d, obtainable from thioketenaminals and α-halogen-ketones, react with primary and secondary amines to afford 2,4-diamino-pyrroles 5a-h. Mercaptobenzen as nucleophilic agent gives the 4-amino-2-phenylthio-pyrrole 5j. Analogously, cyano-(3,5-diphenyl-3H-oxazol-2-ylidene)-acetic acid methyl esters were prepared as intermediates for the synthesis of 2-amino-4-oxo-pyrrolines 10a-d. The isomeric 4-amino-2-oxo-pyrrolines 13a-d can be obtained from 4-amino-2-methoxy-pyrroles, which serves as proof for the position of substituents. The structures were investigated by ¹H and ¹³C NMR spectroscopy.