2,2,7-Trimethyl-2,3-dihydro­quinazolin-4(1H)-one

Ling Zhang; Daxin Shi; Yanqiu Fan; Dongfeng Qian; Jiarong Li

doi:10.1107/S1600536809018480

. 2009 May 20;65(Pt 6):o1345. doi: 10.1107/S1600536809018480

2,2,7-Trimethyl-2,3-dihydroquinazolin-4(1H)-one

Ling Zhang ^a, Daxin Shi ^a, Yanqiu Fan ^a, Dongfeng Qian ^a, Jiarong Li ^a,^*

PMCID: PMC2969724 PMID: 21583197

Abstract

There are two independent molecules in the the asymmetric unit of the title compound, C₁₁H₁₄N₂O. The heterocyclic ring of the bicyclic system has a sofa conformation, with the C atom bearing the two methyl groups displaced by 0.541 (7) Å from the rest of the atoms of the ring [planar to within 0.064 (9) Å]. Molecules are linked into centrosymmetric dimers via N—H⋯O hydrogen bonds.

Related literature

For medicinal and biological properties of dihydroquinazolin-4(3H)-one derivatives, see: Jackson et al. (2007 ▶); Shi et al. (2004 ▶). For a related structure, see: Zhang et al. (2008 ▶).

Experimental

Crystal data

C₁₁H₁₄N₂O
M _r = 190.24
Orthorhombic,
a = 19.538 (4) Å
b = 10.104 (2) Å
c = 20.735 (4) Å
V = 4093.4 (14) Å³
Z = 16
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 113 K
0.18 × 0.16 × 0.12 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.986, T _max = 0.990
31345 measured reflections
3599 independent reflections
3269 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.119
S = 1.07
3599 reflections
274 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809018480/jh2079sup1.cif

e-65-o1345-sup1.cif^{(22.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809018480/jh2079Isup2.hkl

e-65-o1345-Isup2.hkl^{(176.6KB, 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
N1—H1⋯O1ⁱ	0.891 (9)	2.221 (10)	3.0917 (16)	165.7 (14)
N2—H2⋯O2	0.901 (9)	2.029 (10)	2.9144 (15)	167.2 (16)
N4—H4⋯O1	0.897 (9)	1.956 (10)	2.8488 (16)	173.3 (18)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the Beijing Institute of Technology for financial support.

supplementary crystallographic information

Comment

Derivatives of dihydroquinazolin-4(3H)-one are valuable synthetic intermediates featuring common structural motif found in a variety of compounds with interesting medicinal and biological properties (Shi et al., 2004; Jackson et al., 2007).

In the molecule of the title compound (Fig. 1), the 1,3-diazacyclohexane moiety of the bicyclic system has a sofa conformation with the C8 atom displaced by 0.541 (7) Å from the rest of the atoms of the 1,3-diazacyclohexane ring (planar within 0.064 (9) Å). The dihedral angle between C8, C9, C10 plane and the plane (N1, N2, C8) is 89.8 (3)°.

Molecules in crystal are linked into centrosymmetric dimers via N2—H2···O2ⁱ bonds (N2—H2 0.901 (9) Å, H2···O2ⁱ 2.029 (10) Å, N2—H2···O2ⁱ 167.2 (16)°) and N4—H4···O1ⁱ bonds (N4—H4 0.897 (9) Å, H4···O1ⁱ 1.956 (10) Å, N4—H4···O1ⁱ 173.3 (18)°)(Fig. 2).

The molecular geometry and overall crystal structure of the title compound are quite similar to those observed in the structure of its close analog which lacks the methyl substituent in position 6 of the tetrahydroquinalazolinone system (Shi et al., 2003).

Experimental

A solution of 2-amino-5-methylbenzonitrile (10 mmol) and sodium methylate (10 mmol) in acetone (10 ml), was refluxed for 2 h. The reaction mixture was cooled, to room temperature and poured into 20 ml of water (previously cooled to 20°); then it was extracted with ethyl acetate, distilled off ethyl acetate to give the title compound. The product was recrystallizated from ethanol and ethyl acetate to give colorless crystalline powder. m.p. 539–540 K; IR (KBr): 3300 (N—H), 3036, 2972 (C—H), 1642 (C═O) cm^-1; ^1H-NMR (CDCl3, p.p.m.): 1.54 (6H, s), 2.29 (3H, s) 5.89 (1H, s), 6.66 (1H, s), 7.26 (1H, d), 7.78 (1H, d), 8.19 (1H, br). 50 mg of the obtained product was dissolved in ethyl acetate (5 ml) and the solution was kept at room temperature for 4 d to give colorless single crystals.