o-Phenylenediamine as a Source of Fused Azole, Azine, and Diazepine Derivatives

Abstract

A facile synthetic approach to diazepine and/or benzimidazole derivatives has been developed through the reaction of enamine [N 1 -(1-phenylethenyl)benzene-1,2-diamine] obtained from o-phenylenediamine and acetophenone. Its reaction with isophthaloyl chloride produced bis(1,5-benzodiazepinyl)benzene derivative via cyclization involving the nucleophilic enamino carbon atom, whereas the cyclocondensation with diethyl succinate occurred at the nucleophilic nitrogen atom to give bis-benzimidazole derivative. Depending on the conditions, the cyclization with carbon disulfide in DMSO afforded tricyclic 4-phenylimidazo[4,5,1-hi]indole-2(1H)-thione, while 4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-thione was formed in the presence of pyridine. Cyclocondensation of o-phenylenediamine with two equivalents of acetophenone in acid medium produced 3-phenyl-1-(1-phenylethenyl)-1,4-dihydroquinoxaline. N-(2-Aminophenyl)thiourea obtained from o-phenylenediamine and ammonium thiocyanate reacted with chloroacetyl chloride, diethyl malonate, carbon disulfide, and sodium nitrite in aqueous HCl to afford benzimidazole, thiadiazolobenzimidazole, and benzotriazole derivatives.

Decoration, Characterization and Antimicrobial Activity Evaluation of Novel Nano‐Based 1,2‐Phenylenediamine Functionalized Maleic Anhydride‐Allylphenyl Ether Conjugate

“…This study also paved the way for the synthesis of other fused nitrogen-containing heterocyclic compounds with a broad spectrum of bioactivity. [33] For example, benzofused core heterocyclic compounds have many biological properties such as antitumor [34] and antirotaviral [35] activities. The reactions of o-PDA as a binucleophilic nitrogen system have been studied in a variety of ways to derive seven-, six-, and five-membered heterocyclic compounds.…”

“…Shehta and co‐workers proposed a simple laboratory strategy for the practical synthesis of some fused heterocyclic systems by cyclization of o ‐PDA with various reagents. This study also paved the way for the synthesis of other fused nitrogen‐containing heterocyclic compounds with a broad spectrum of bioactivity [33] . For example, benzofused core heterocyclic compounds have many biological properties such as antitumor [34] and antirotaviral [35] activities.…”