title: The formation of 2,2,4-trimethyl-2,3-dihydro-1H-1,5-benzodiazepine from 1,2-diaminobenzene in the presence of acetone.
abstract: In an attempt to synthesize a 2-substituted benzimidazole from the reaction of o-phenylenediamine and isophthalic acid in the presence of acetone and ethanol under microwave irradiation, a salt of the isophthalate ion and 2,2,4-trimethyl-2,3-dihydro-1H-1,5-benzodiazepin-5-ium ion was obtained. The condensation of two moles of acetone with the amine groups resulted in the formation of the benzodiazepine which crystallized as an iminium cation forming a salt with the isophthalate anion. The formation of benzodiazepine was also confirmed by performing the reaction of o-phenylenediamine with excess acetone in ethanol under conventional heating conditions. The compounds were characterized by NMR, FTIR, HRMS and microanalysis as well as X-ray crystallography. The reaction mechanism leading to the formation of benzodiazepine is also discussed.
authors.affiliation: Department of Chemistry, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031, South Africa. zenixole.tshentu@nmmu.ac.za.
authors.forename: Felix
authors.initials: F
authors.lastname: Odame
authors.forename: Phumelele
authors.initials: P
authors.lastname: Kleyi
authors.forename: Eric
authors.initials: E
authors.lastname: Hosten
authors.forename: Richard
authors.initials: R
authors.lastname: Betz
authors.forename: Kevin
authors.initials: K
authors.lastname: Lobb
authors.forename: Zenixole
authors.initials: Z
authors.lastname: Tshentu
mesh_terms: D000096:Acetone / Q000737:chemistry*; D001569:Benzodiazepines / Q000737:chemistry*; D010655:Phenylenediamines / Q000737:chemistry*
chemical_list: D010655:Phenylenediamines; D001569:Benzodiazepines; D000096:Acetone; C034193:1,2-diaminobenzene