Crystal Structure of 6-Pridyl-5,6-dihydrobenzo[4,5]-imidazo[1,2-c]quinazoline

Abstract

The N-heterocycles are of considerable importance in view of their presence in several biological systems. Benzimidazole derivatives and their metal complexes exhibit anti-bacterial, veterinary, anti-helmintic, insecticidal and virucidal activities. 1 Multidentate N-heterocycles produce organized supramolecules on coordination to metal ions and they appear quite promising for the design of stable light conversion devices. 2In this direction, some of the multidentate N-heterocycles and their complexes have been prepared and characterized. As part of our continuing research in the field of syntheses of nitrogencontaining heterocyclic ligands and their metal complexes with palladium and rhodium, 3 we are reporting here the synthesis and crystal structure of 6-pyridyl-5,6-dihydrobenzo [4,5]The synthesised ligand was characterized by physical, spectral and single crystal X-ray structural analyses.o-Aminophenylbenzimidazole (0.05 mol: 10.45 g) was dissolved in 200 ml of alcohol. To this, 2-pyridylinaldehyde (0.05 mol; 4.75 g) was added, and the mixture was refluxed for 4 -5 hours. The chemical structure is as shown in Fig. 1. A yellow compound was obtained. It was concentrated under reduced pressure. The solid was recrystallized from methanol to get a pure compound. A suitable crystal for X-ray analysis was grown by the slow evaporation method using methanol as solvent.A single crystal of the title ligand of dimensions 0.2 × 0.4 × 0.5 mm was chosen for X-ray diffraction studies. The measurements were made on a Rigaku AFC7S diffractometer with graphite-monochromated radiation (Mo Kα). The data were collected using the ω-2θ scan technique and reduced using the teXsan data reduction program. 4 Lorentz and polarization corrections were applied. The structure was solved by direct methods and refined by a full-matrix least squares method with anisotropic temperature factors for the non-H atoms. All the H atoms were placed at chemically acceptable positions and were refined with isotropic temperature factors. The experimental crystallographic details are given in Table 1.The final coordinates and equivalent thermal parameters of non-H atoms are listed in Table 2. Table 3 gives the bond distances and angles of non-hydrogen atoms. The bond distances and bond angles are in good agreement with the standard values. The title compound C19H12N4 was synthesised and the structure was investigated by X-ray crystallography. It crystallizes in the monoclinic space group P21/c with cell parameters a = 8.697(9)Å, b = 13.045(10)Å, c = 13.271(4)Å, β = 97.38(4)å nd Z = 4. The final residual factor is 0.0628.

Synthesis and Crystal Structure of 6-Furyl-5,6-dihydrobenzoimidazo-[1,2-c]quinazoline Monohydrate

“…This is comparable with the corresponding value of 87.4(2)˚ reported for 6-pyridyl-5,6dihydrobenzo [4,5]-imidazo [1,2-c]quinazoline. 4 A study of the torsion angles, asymmetric parameters and least-squares plane calculations reveals that the dihydropyrimidine ring is in an envelope conformation. A ring-puckering 5 analysis shows that the dihydropyrimidine ring has a puckering amplitude of Q2 = 0.2914(27)Å, a weighted average ring bond distance of 1.4117(14,170)Å and a weighted average absolute torsion angle of 23.34(15,658)˚.…”

“…The furyl ring plane is nearly orthogonal to the dihydrobenzimidazo quinazoline plane, as indicated by the dihedral angle value of 86.26(1)˚. This is comparable with the corresponding value of 87.4(2)˚ reported for 6-pyridyl-5,6dihydrobenzo [4,5]-imidazo [1,2-c]quinazoline. 4 A study of the torsion angles, asymmetric parameters and least-squares plane calculations reveals that the dihydropyrimidine ring is in an envelope conformation.…”

6-Phenyl-5,6-dihydrobenzoimidazo[1,2-c]quinazoline

“…Most of the bond lengths and angles have normal values and are comparable to those reported in similar structures (Elgemeie et al, 1998;Low et al, 2002Low et al, , 2003Jayalakshmi et al, 2004). The benzene and imidazole rings are planar, but the quinazoline ring system deviates from planarity, with atom C10 lying 0.4707 (16) Å from the N7/C8/C13/C12/N11 leastsquares plane.…”

“…Substituted quinazoline have fungicidal, antimicrobial, anti-inflammatory, anticancer, antihypertensive and anti-HIV activities (Alexandre et al, 2003;De Clercq, 2001). Few X-ray crystal structure reports for benzimidazoquinazolines has been carried out (Elgemeie, et al, 1998;Low et al, 2003;Jayalakshmi, et al, 2004). In view of the above observations, the title compound, (I), was synthesized and its crystal structure is reported here (Fig.…”

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

“…It was separated and recrystallized from ethanol to get 6-p-dimethylaminophenyl-5,6-dihydrobenzoimidazo [1,2-c] quinazoline (I) as a cream crystalline solid. Compounds II through V were prepared as reported earlier [24][25][26][27].…”