Synthesis, crystal structure, structural characterization and in vitro antimicrobial activities of 1-methyl-4-nitro-1H-imidazole

Abstract

We report new reaction conditions (less corrosive reagents) for the regio-specific synthesis, spectroscopic properties, crystal structure, antimicrobial activities and MICs of 1-methyl-4-nitro-1H-imidazole (I). For structure confirmation, X-ray crystallography was performed using crystals obtained from chloroform and hexane (1:1). The structure of the compound (I) was further characterized by FTIR, 1H NMR, 13C NMR and EIMS. Important peaks appearing in the EIMS, at the m/z=127, 111, 97, 81, and 54 arise due to the loss of single electron, loss of O, NO, NO2, and loss of NO2 & HCN respectively. The high intensity peak in the EIMS at m/z=42 arises due to the loss of NO, CO and HCN from the molecular ion. The correct 1H NMR (400MHz, CDCl3) of (I) shows peaks at 7.76 (ArH, HCN), 7.42 (ArH, HCC), and 3.82 (N–CH3)ppm. Further structural studies showed that the driving force for crystallization (self-assembly) and hydrogen bonding (C–H…O–NO, 2.57Å) originates from the partial negative oxygen of the nitro (NO2) group at one end and the partial positive hydrogen (N–CH3) at another corner of the molecule. Biological assay against many (13) microorganisms and fungi showed that the title compound (I) is moderately active against Gram (+), Gram (−) bacteria and fungi.