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-1 H -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, 1 H NMR, 13 C 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, NO 2 , and loss of NO 2 & 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 1 H NMR (400 MHz, CDCl 3 ) of (I) shows peaks at 7.76 (ArH, HC N), 7.42 (ArH, HC C), and 3.82 (N–CH 3 ) ppm. Further structural studies showed that the driving force for crystallization (self-assembly) and hydrogen bonding (C–H…O–NO, 2.57 A) originates from the partial negative oxygen of the nitro (NO 2 ) group at one end and the partial positive hydrogen (N–CH 3 ) 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.