Methyl 4-(4-chlorophenyl)-8-iodo-2-methyl-6-oxo-1,6-dihydro-4H-pyrimido[2,1-b]quinazoline-3-carboxylate

In the title compound, C20H15ClIN3O3, the dihedral angle between the quinazolinone ring system [r.m.s. deviation = 0.047 (2) Å] and the pendant benzene ring is 82.63 (11)°. The molecular conformation is stabilized by intramolecular C—H⋯O interactions. In the crystal, the molecules are linked by N—H⋯O hydrogen bonds into chains along the a-axis direction. Another set of chains propagating along [101] is formed due to intermolecular I⋯Cl short contacts of 3.427 (1) Å, thus giving layers parallel to (010). The layers are connected by C—H⋯π and π–π interactions, the shortest distance between the centroids of aromatic rings being 3.8143 (16) Å.

In the title compound, C 20 H 15 ClIN 3 O 3 , the dihedral angle between the quinazolinone ring system [r.m.s. deviation = 0.047 (2) Å ] and the pendant benzene ring is 82.63 (11) . The molecular conformation is stabilized by intramolecular C-HÁ Á ÁO interactions. In the crystal, the molecules are linked by N-HÁ Á ÁO hydrogen bonds into chains along the a-axis direction. Another set of chains propagating along [101] is formed due to intermolecular IÁ Á ÁCl short contacts of 3.427 (1) Å , thus giving layers parallel to (010). The layers are connected by C-HÁ Á Á andinteractions, the shortest distance between the centroids of aromatic rings being 3.8143 (16) Å .

Comment
In continuation of our work on the pharmacological properties and single-crystal X-ray studies (Nayak et al., 2010(Nayak et al., , 2011aVenugopala et al., 2012) on dihydropyrimidine derivatives, we synthesized the title compound as a potential anti-malarial agent. Here we are reporting the single-crystal structure of the title compound.

Refinement
All H atoms were positioned geometrically with N-H = 0.88 Å, C-H = 0.95-1.00 Å and refined using a riding model with U iso (H) = 1.2 U eq (C/N) except for the methyl group where U iso (H) = 1.5 U eq (C).

Figure 1
A view of the title compound with the atom numbering scheme and displacement ellipsoids for non-H atoms drawn at the 50% probability level. The intramolecular C-H···O interactions are shown by dashed lines.

Figure 2
Intermolecular N-H···O hydrogen bonds and short contacts I···Cl forming layers parallel to (010). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.003 Δρ max = 0.89 e Å −3 Δρ min = −0.52 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. 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 > 2σ(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.