2-(4-Chlorophenyl)-4-phenyl-1,2-dihydroquinazoline

In the title compound, C20H15ClN2, the pyrimidine ring is in a flattened half-chair conformation. The phenyl and chloro-substituted benzene rings form dihedral angles of 84.97 (5) and 80.23 (4)°, respectively, with the benzene ring of the dihydroquinazoline group. The dihedral angle between the phenyl and chloro-substituted benzene rings is 61.71 (5)°. In the crystal, molecules are arranged in intersecting layers parallel to (101) and (-102), with N—H⋯N hydrogen bonds linking molecules along [010]. In addition, a weak C—H⋯π interaction is observed.

In the title compound, C 20 H 15 ClN 2 , the pyrimidine ring is in a flattened half-chair conformation. The phenyl and chlorosubstituted benzene rings form dihedral angles of 84.97 (5) and 80.23 (4) , respectively, with the benzene ring of the dihydroquinazoline group. The dihedral angle between the phenyl and chloro-substituted benzene rings is 61.71 (5) . In the crystal, molecules are arranged in intersecting layers parallel to (101) and (102), with N-HÁ Á ÁN hydrogen bonds linking molecules along [010]. In addition, a weak C-HÁ Á Á interaction is observed.

Comment
Heterocyclic chemistry is a potential part of the synthetic organic chemistry, covering a wide variety of bioactive molecules. Among six-membered heterocycles, quinazoline occupies significant position and is commonly found in a wide variety of natural products, synthetic pharmaceutical molecules, and other functional materials (Gundla et al., 2008;Luth & Lowe, 2008). Quinazoline derivatives are among the most potent tyrosine kinase and cellular phosphorylation inhibitors (Fry et al., 1994), and they also show remarkable activity as antitubercular, antiviral, and anticancer agents (Kunes et al., 2000). The growing medicinal importance of these heterocycles perpetuates to provide strong rationale for the development of synthetic methods for their preparation. These efforts have led to several reviews emphasizing the synthesis (Michael, 2002;Frère et al., 2003;Langer & Bodtke, 2003), and biological evaluation of quinazolines.
In the course of a program directed toward the synthesis of new heterocyclic systems for pharmacological evaluation, we report herein the crystallographic study and the synthesis of the title compound. The molecular structure is shown in  (Table 1).
After completion of the reaction as monitored by TLC, the reaction was poured into ice cold water; solid product was filtered, washed with water and dried. The crude product was recrystallized from ethyl acetate to give the tite compound as a yellow solid (m.p. 415-417 K). X-ray quality crystals were grown from a solution of the title compound in ethyl acetate.

Refinement
H atoms bonded to C atoms were initially located in a difference Fourier map. However, they were subsequently placed in idealized positions and refined in a riding-model approximation. The applied constraints were as follows: C aryl -H aryl = 0.93 Å; C methine -H methine = 0.98 Å; U iso (H aryl H methine ) = 1.2U eq (C aryl /C methine ). Atom H1N was located in a difference Fourier map and refined isotropically.

Figure 1
The molecular structure with displacement ellipsoids drawn at the 50% probability level.   Part of the crystal structure showing the hydrogen bonds N-H···N as dashed red lines. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.