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, 1 H NMR, 13 C 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 P2 1 /n with the unit cell parameters a = 10.652(2) Å , b = 11.002(2) Å , c = 15.753(2) Å , b = 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, 1 H and 13 C NMR spectral studies along with structural comparison.

Binding site-driven sensing properties of a quinazoline derivative with metal cations

“…S1 †) is the same as reported. 15 The selected bond distances and angles were tabulated in Table S1. †…”

“…8(a), proton signals of L were assigned similarly as the reported. 15 The binding modes of L with Al 3+ was studied by 1 H NMR titration, shown in Fig. 8(a-d).…”

An Extensive Analysis of Current Synthetic Methodologies and Applications of Imidazo/Benzimidazo[1,2‐c]Quinazolines

“…Natarajan et al introduced a series of 5,6-dihydrobenzoimidazo[1,2-c]quinazoline (6 a-e) with the progression of their antibacterial activity in this respect (Figure 7). [21] The antimicrobial activity of 6 a-c against the bacterial strain Bacillus subtilis and the fungus Yeast reveals that substances 6 a and 6 b are somewhat more toxic than the standard in terms of Yeast but exhibit no toxicity in terms of Bacillus subtilis. The electron donating substituents in para position (dimethyl amino group in 6 a and hydroxyl group in 6 b) are unlikely to hinder bacterial growth.…”

Synthesis, antimicrobial, and mitotic toxicity evaluation of new 6‐substituted 2‐(benzo[4,5]imidazo[1,2‐c]quinazolin‐5(6H)‐yl)acetic acids

“…[ 11–15 ] The cyclization of the resulting 2‐(1 H ‐benzo[ d ]imidazol‐2‐yl)aniline with different aldehydes, acyl chlorides, or orthoesters gives 6‐substituted 5,6‐dihydrobenzo‐ or benzo[4,5]imidazo[1,2‐ c ]quinazolines, respectively. [ 2,12,16–25 ] Besides, the fusion of 2‐substituted 4 H ‐3,1‐benzoxazin‐4‐one with 1,2‐phenylenediamine also yields quite good results. [ 26–28 ]…”

“…[11][12][13][14][15] The cyclization of the resulting 2-(1H-benzo[d]imidazol-2-yl)aniline with different aldehydes, acyl chlorides, or orthoesters gives 6-substituted 5,6-dihydrobenzo-or benzo [4,5]imidazo [1,2-c]quinazolines, respectively. [2,12,[16][17][18][19][20][21][22][23][24][25] Besides, the fusion of 2-substituted 4H-3,1-benzoxazin-4-one with 1,2-phenylenediamine also yields quite good results. [26][27][28] It should be noted that despite the large number of publications on the synthesis of benzo [4,5]imidazo [1,2-c] quinazolines their 5,6-disubstituted derivatives are almost unknown.…”