6,7,8,9,10,11-Hexahydro-13H-azocino[2,1-b]quinazolin-13-one

The title compound, C14H16N2O, is a synthetic analogue of quinazolone alkaloids with pyrrilo, pyrido and azopino rings. The quinazolinic part of the molecule is generally planar within 0.037 (3) Å; the eight-membered ring exhibits an intermediate conformation between the chair and boat forms as it is typical for cyclooctene rings. An ethylene group of the azopino ring is disordered over two positions with a refined occupancy ratio of 0.910 (7):0.090 (7). In the crystal, the H atoms of the aromatic rings form weak C—H⋯O and C—H⋯N hydrogen bonds. One C—H⋯O hydrogen bond leads to the formation of a one-dimensional chain. Another C—H⋯O and a C—H⋯N bond link these chains, generating a three-dimensional network.

The title compound, C 14 H 16 N 2 O, is a synthetic analogue of quinazolone alkaloids with pyrrilo, pyrido and azopino rings. The quinazolinic part of the molecule is generally planar within 0.037 (3) Å ; the eight-membered ring exhibits an intermediate conformation between the chair and boat forms as it is typical for cyclooctene rings. An ethylene group of the azopino ring is disordered over two positions with a refined occupancy ratio of 0.910 (7):0.090 (7). In the crystal, the H atoms of the aromatic rings form weak C-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds. One C-HÁ Á ÁO hydrogen bond leads to the formation of a one-dimensional chain. Another C-HÁ Á ÁO and a C-HÁ Á ÁN bond link these chains, generating a three-dimensional network.
The quinazoline part of the molecule is a generally flat within a standard deviation of ±0.037 Å. The electronic system of the N7-C14-N15-C12 fragment of the pyrymidinic ring is delocalized as reflected by the bond lengths. The length of the formal double bond N7═C14 and the single bond C14-N15 in the structure of the title compound are 1.297 (3) and 1.383 (3) Å, respectively, which is in agreement with the range observed in crystals of pyrrilo, pyrido, and azopino quinazolones . The length of the C═O bond (1.227 (3) Å) is also compareable to those observed in above mentioned analogues. The eight-membered ring has taken on an intermediate form between a chair and boat conformation typical for cycloectene rings (Barnes et al., 1992).
In the crystal structure of the title compound weak intermolecular C-H···X hydrogen bonds are observed as it is often the case in alkaloids (Rajnikant et al., 2005). The hydrogen bond C8-H8A···O1 i leads to the formation of a one dimensional chain. Another C-H···O and a C-H···N bond (C10-H10A···O1 iii and a C9-H9A···N7 ii ) link these chains to generate a three-dimensional network ( Fig. 2 and 3; for numerical values and symmetry operators see Table 1).

Experimental
The title compound was synthesized on the basis of a well-known method (Shakhidoyatov, et al., 1976). Powder of title compound was dissolved in hot aqueous ethanol and from the solution yellow prismatic crystals were obtained during slow evaporation in a thermostat at a temperature of 313 K.

Refinement
In the absence of anomalous scatteres and using molybdenum radiation Friedel pairs were merged prior to refinement. The C3 and C4 atoms of the molecule are disordered over two positions (C3, C3', C4, C4'). Refinement of the structure by using a free variable for the occupancy led to a ratio for the disordered atoms of 0.910 (7):0.090 (7). The bond lengths of the disordfered hexamethylenic fragment were restrained to be the same within a standard deviation of 0.02 Å.
supplementary materials sup-2 The H atoms bonded to C atoms were placed geometrically (with C-H distances of 0.97 Å for CH 2 and 0.93 Å for C ar ) and included in the refinement with a riding motion approximation with U iso = 1.2U eq (C) [U iso = 1.5U eq (C) for methyl H atoms]. Fig. 1. The molecular structure of the title compound, with 50% probability displacement ellipsoids (bonds of the minor disordered moiety are represented by dashed lines).   6,7,8,9,10,