Synthesis and Reactions of Bis Amino Pyrroles Based Benzoin

Abstract

A series of diamines, including ethane-1,2-diamine, hydrazine hydrate, and isomeric phenylenediamines (o-, m-, p-) as well as benzidine, were reacted with benzoin in the presence of malononitrile and pyridine catalyst. The reactions primarily yielded bis-pyrrole derivatives (I, III, IV, and VI), except for ethane-1,2-diamine, which predominantly formed a furan derivative (II). In contrast, hydrazine hydrate and o-phenylenediamine did not produce bis-pyrroles, instead yielding a hydrazone derivative (V) and a quinoxaline derivative (VII), respectively. Further derivatization of selected bis-pyrroles (I, IV) and the furan compound (II) with acetic anhydride afforded the corresponding amide derivatives (VIII, IX, and X). All syntheses were performed under mild conditions using straightforward procedures, yielding moderate product quantities. The synthesized compounds (I–X) were thoroughly characterized by melting point analysis, TLC, IR, ¹H NMR (including D₂O exchange), ¹³C NMR, and APT techniques.