2-Phenyl-4H-3,1-benzoxazin-4-one

R Thilagavathy; Helen P Kavitha; R Arulmozhi; Jasmine P Vennila; V Manivannan

doi:10.1107/S1600536808042050

. 2008 Dec 17;65(Pt 1):o127. doi: 10.1107/S1600536808042050

2-Phenyl-4H-3,1-benzoxazin-4-one

R Thilagavathy ^a, Helen P Kavitha ^a, R Arulmozhi ^b, Jasmine P Vennila ^c, V Manivannan ^d,^*

PMCID: PMC2968047 PMID: 21581588

Abstract

The title molecule, C₁₄H₉NO₂, is nearly planar with a dihedral angle of 3.72 (4)° beteewn the plane of the phenyl ring and the 3,1-benzoxazin-4-one fragment. The molecules are arranged into stacks parallel to the b axis via π–π stacking interactions [centroid-centroid distance = 4.2789 (11) Å] and the crystal packing is additionally stabilized by weak intermolecular C—H⋯O interactions.

Related literature

For the biological activity of oxazin-4-ones, see: Pietsch & Gütschow (2005 ▶); Tarzia et al. (2007 ▶). For similar structures, see: Crane & Rogerson (2004 ▶); Khan et al. (2007 ▶).

Experimental

Crystal data

C₁₄H₉NO₂
M _r = 223.22
Monoclinic,
a = 13.3055 (16) Å
b = 3.8930 (4) Å
c = 20.445 (2) Å
β = 94.946 (3)°
V = 1055.1 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 295 (2) K
0.20 × 0.16 × 0.16 mm

Data collection

Bruker Kappa APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.981, T _max = 0.985
13688 measured reflections
3034 independent reflections
1800 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.187
S = 1.08
3034 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808042050/gk2180sup1.cif

e-65-0o127-sup1.cif^{(15.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808042050/gk2180Isup2.hkl

e-65-0o127-Isup2.hkl^{(145.9KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10⋯O2ⁱ	0.93	2.51	3.294 (2)	142

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the management of SRM University for providing financial assistance for the pilot project.

supplementary crystallographic information

Comment

Oxazin-4-one derivatives are used as inhibitors of the alpha/beta hydrolases, cholesterol esterase and acetylcholinesterase (Pietsch & Gütschow, 2005) and are potent inhibitors of the endocannabinoid-deactivating enzyme, monoacylglycerol lipase (Tarzia et al., 2007).

The geometric parameters of the title molecule (Fig. 1) agree well with the earlier reported structures (Crane & Rogerson, 2004; Khan et al., 2007). The plane of the phenyl ring forms a dihedral angle of 3.72 (4)° with the benzo[d][1,3]oxazin-4-one moiety. The molecular structure is stabilized by weak intramolecular C–H···O interaction and the crystal packing is stabilized by weak intermolecular C—H···O and π-π stacking interactions.

Experimental

To a stirred solution of anthranilic acid (0.01 mol) in pyridine (60 ml), benzoyl chloride (0.01 mol) was added dropwise maintaining the temperature near 8° C for one hour. The reaction mixture was stirred for another 2 h at room temperature. While stirring, a solid product separated out. The whole reaction mixture was neutralized with NaHCO₃ solution. A pale yellow solid deposited was filtered, washed with water and recrystallized from ethanol to get diffraction quality crystals; yYield 78%.