Molecular and Crystal Structure of N-(8-benzylidene-4-phenylhexahydroquinazolin-2(1H)-ylidene)Cyanamide

We have obtained previously known and new 4,8-C-substituted hexahydroquinazolincyanamides by two-component condensation of 2,6-diaryl(heteroaryl)methylidenecyclohexanones with the same or different terminal substituents with N-cyanoguanidine according to a modified procedure under conditions of basic catalysis. We have grown a singlecrystal of one of the representatives of the series –N-(8-benzylidene-4-phenylhexahydroquinazolin-2(1H)-ylidene)cyanamideby crystallization from a saturated solution of acetonitrile and carried out its X-ray diffraction study. The structure of N-(8-benzylidene-4-phenylhexahydroquinazolin-2(1H)-ylidene)cyanamide, C₂₂H₂₀N₄, has orthorhombic (P2₁2₁2₁) symmetry. The molecule is built from fused non-planar cyclohexene and tetrahydropyrimidine rings. The cyclohexene ring is in the half-chair conformation, while the tetrahydropyrimidine ring adopts the ‘C-envelope’ conformation. The crystal packing of the compound is an alternating layered structure. The mutual arrangement of molecules promotes the formation of intermolecular hydrogen bonds (IMH) between the H1 hydrogen atoms of the quinazoline ring and the N4 nitrogen atoms of the nitrile group. Non-planar C–H···π interactions are observed in the crystal as well. The compound is in the E,E-configuration. The calculation and analysis of Hirschfeld surfaces demonstrated the presence of hydrogen bonds, different in energy, and C–H···π interactions between benzene rings and protons of other benzene rings of neighbouring molecules in both the benzylidene and phenyl substituents.

Graphical Abstract

X-ray diffraction analysis of hexahydroquinazolincyanamide showed that there are intermolecular hydrogen bonds with the hydrogen atoms of the quinazoline ring and the nitrogen atoms of the nitrile and imine groups. An assessment of the intermolecular stacking interaction is given.