ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Benzimidazoles. IV. Preparation, infrared, and ultraviolet absorption spectra of 1-methyl-2-aryl-5-nitrobenzimidazoles

A. Jurášek and R. Kada

Department of Organic Chemistry, Slovak Technical University, Bratislava

Abstract: By treatment of 4-nitro-2-amino-N-methylaniline with p-substituted benzaldehydes in nitrobenzene new 1-methyl-2-(4-X-phenyl)-5-nitrobenzimidazoles were prepared, where X = CH₃, CI, Br, I, COOCH₃. Infra-red absorption spectra of the described substances and those, where X = H, OCH₃ and N(CH₃)₂ in the 1800—1200 cm^-1 range are discussed and the electron absorption spectra in the near ultra-violet region are compared with those of isomeric 1-(4-X-phenyl)-2-methyl-5-nitrobenzimidazoles. It was found that the displacement of phenyl group from carbon C₍₁₎ to C₍₂₎ in 5-nitrobenzimidazoles resulted in formation of absorption bands corresponding to the benzenoid л→л* electron transition, whereas bands attributed to the electron transition in the imidazole ring remain „hidden".

Full paper in Portable Document Format: 224a257.pdf (in Slovak)

Chemical Papers 22 (4) 257–262 (1968)