Synthesis and antimicrobial evaluationof benz [b]-1,4-thiazepine, benz[b]-1,4-diazepine,and quinoxaline derivatives via green mechanochemical and conventional techniques

Mechano heterocyclic chemistry (MHC) is a recent and quickly growing technique in synthesis of heterocycles. Benzo[b]1,4-thiazepines,benzo[b]1,4-diazepines\were prepared via new mechano-chemical (grinding)technique of α,β-epoxyketoneswith o-aminothiophenol, and o-phenylenediamine, respectively. The same compounds were synthesized under conventional thermal method. However, quinoxalines were obtained from α,β-epoxyketones and o-phenylenediamine, mainly under conventional method. We introduced the yield economy [YE] as a metric to assess the conversion efficiency of grinding and conventional synthetic reactions. Notably, the mechano-chemical reaction provides a green facile access of thiazepines, diazepines,andquinoxalines in excellent yields, as well as providing higher yield economy [YE] compared with conventional thermal methods. The antimicrobial activity of some of the synthesized heterocycles was tested.