Synthesis,Characterization and Biological Activity Studies on 6-<Emphasis Type="Italic">p</Emphasis>-Dimethylaminophenyl-5,6-dihydrobenzoimidazo[1,2-<Emphasis Type="Italic">c</Emphasis>]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-dihydrobenzoimidazo1,2-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) ?, b = 11.002(2) ?, c = 15.753(2) ?, 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-dihydrobenzoimidazo1,2-c]quinazoline; 6-phenyl-5,6-dihydrobenzoimidazo1,2-c]quinazoline; 6-pyridyl-5,6-dihydrobenzoimidazo1,2-c]quinazoline; 6-furyl-5,6-dihydrobenzoimidazo1,2-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.