The present paper elicits the zinc oxide nanoparticles-assisted synthesis of a new series of seven-membered 1,4-diazepine heterocyclic compounds as potent lead scaffolds. Structures of synthesized compounds were corroborated using spectroanalytical techniques viz, FT-IR, 1H, 13C NMR, Mass, and elemental analysis. Also, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Energy dispersive x-ray analysis (EDAX), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FT-IR) were used to establish the structure and morphology of the synthesized nanocatalyst. The clean workup procedure, high to excellent yields, relatively short reaction times, and high atom economy are the incredible advantages associated with the protocol.

Kinetic studies were made of the reactions between triphenylphosphine 1 and dialkyl acetylenedicarboxylates 2, in the presence of NH-acids, such as benzotriazole, 5-methylbenzotriazole or 5-chlorobenzotriazole 3 (as a protic/nucleophilic reagent). To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometry. Useful information was obtained from studies of the effect of solvent, structure of reactants (dialkyl acetylenedicarboxylates and NH-acids) and also concentration of reactants on the reaction rates. First and third steps (k2, k3) of all reactions were recognized as a rate determining and fast steps, respectively. Proposed mechanism was confirmed on the basis of experimental data.