Synthesis, Characterization and Biological Activity Studies on 6-p-Dimethylaminophenyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline: Crystal Structure of the Title Compound and Comparative Study with Related Derivatives

Abstract

Reaction of o-aminophenylbenzimidazole with p-dimethylaminobenzaldehyde yielded 6-p-dimethylaminophenyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline, which was characterized by elemental analysis, IR, UV–Vis, 1H NMR, 13C NMR, mass spectral studies and X-ray crystal structure analysis. Studies on the antimicrobial activity of the compound revealed that it is active against fungus Yeast but not Bacillus subtilis. The compound crystallized in the space group P21/n with the unit cell parameters a = 10.652(2) A, b = 11.002(2) A, c = 15.753(2) A, β = 109.29(2)° and the structure was refined to an R-factor of 0.0479. The hydropyrimidine ring in the quinazoline moiety is in skew-boat conformation. The dimethylamino group attached to phenyl ring is in conjugation with it. The structure was stabilized by intermolecular C–H–N interactions. A few of the related quinazolines (6-p-hydroxyphenyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline; 6-phenyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline; 6-pyridyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline; 6-furyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline) were also examined for their biological activity, in addition to their characterization by IR, UV–Vis, 1H and 13C NMR spectral studies along with structural comparison. The details regarding the synthesis, spectroscopic analysis, crystal structure and biological activity of the title compound are reported in this paper.