3-Benzyl-6-methyl-2-sulfanylidene-2,3-di­hydroquinazolin-4(1H)-one

Rashad Al-Salahi; Mohamed Al-Omar; Hussein El-Subbagh; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536812006009

. 2012 Feb 17;68(Pt 3):o717–o718. doi: 10.1107/S1600536812006009

3-Benzyl-6-methyl-2-sulfanylidene-2,3-dihydroquinazolin-4(1H)-one

Rashad Al-Salahi ^a, Mohamed Al-Omar ^b, Hussein El-Subbagh ^c, Madhukar Hemamalini ^d, Hoong-Kun Fun ^d,^*,^‡

PMCID: PMC3295489 PMID: 22412600

Abstract

In the title compound, C₁₆H₁₄N₂OS, the quinazoline ring system is essentially planar, with a maximum deviation of 0.029 (3) Å. The dihedral angle between the quinazoline and benzene rings is 88.4 (2)°. In the crystal, adjacent molecules are connected via pairs of N—H⋯S and C—H⋯O hydrogen bonds, which generate R ² ₂(8) and R ² ₂(10) graph-set motifs, respectively, resulting in a supramolecular chain along the a axis.

Related literature

For details and applications of quinazoline compounds, see: Roth & Fenner (2000 ▶); Jantova et al. (2004 ▶); Harris & Thorarensen (2004 ▶); Andries et al. (2005 ▶); Al-Rashood et al. (2006 ▶); Ghorab et al. (2007 ▶); Rádl et al. (2000 ▶); Klepser & Klepser (1997 ▶); Al-Omar et al. (2004 ▶); Al-Omary et al. (2010 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₆H₁₄N₂OS
M _r = 282.35
Monoclinic,
a = 24.2438 (18) Å
b = 5.1618 (5) Å
c = 24.4265 (17) Å
β = 111.532 (6)°
V = 2843.4 (4) Å³
Z = 8
Cu Kα radiation
μ = 1.99 mm⁻¹
T = 296 K
0.83 × 0.12 × 0.06 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.289, T _max = 0.890
9528 measured reflections
2592 independent reflections
1421 reflections with I > 2σ(I)
R _int = 0.104

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.166
S = 0.93
2592 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812006009/is5070sup1.cif

e-68-0o717-sup1.cif^{(23.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812006009/is5070Isup2.hkl

e-68-0o717-Isup2.hkl^{(124.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812006009/is5070Isup3.cml

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—H1A⋯S1ⁱ	0.86	2.50	3.335 (3)	165
C4—H4A⋯O1ⁱⁱ	0.93	2.41	3.295 (4)	159

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

RAS, MAO and HES express their gratitude to Mr Hazem Ghabbour, X-ray Division of the Pharmaceutical Chemistry Department, King Saud University, for valuable help in the determination of the X-ray crystal structure. MH and HFK thank the Malaysian Government and Universiti Sains Malaysia for Research University Grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a postdoctoral research fellowship.

supplementary crystallographic information

Comment

Quinazoline moiety is present in many classes of biologically-active compounds. A number of them have been clinically used as antifungal, antibacterial and antiprotozoic drugs (Roth & Fenner, 2000; Jantova et al., 2004; Harris & Thorarensen, 2004), as well as antituberculotic agents (Andries et al., 2005). Furthermore, they have drawn much attention due to their broad range of pharmacological properties which include antitumor (Al-Rashood et al., 2006), anticancer (Ghorab et al., 2007) and analgesic (Rádl et al., 2000) properties. Certain quinazoline analogs also showed remarkable activity against the opportunistic infections of Pneumocystis carinii and Toxoplasma gondii. Those microorganisms proved to be the priniciple cause of death in patients with immunocompromised diseases such as acquired immune deficiency syndrome (Klepser & Klepser, 1997). This work is a continuation of this program with the aim of obtaining an interesting series of quinazolines that contain the thioxo functional group which was identified as a possible pharmacophore of the antimicrobial activity (Al-Omar et al., 2004; Al-Omary et al., 2010).

The molecular structure of the title compound is shown in Fig. 1. The quinazoline (N1,N2/C1–C8) ring is essentially planar, with a maximum deviation of 0.029 (3) Å for atom C2. The dihedral angle between the quinazoline (N1,N2/C1–C8) and the benzene (C10–C15) rings is 88.4 (2)°. The bond lengths (Allen et al., 1987) and angles are within normal ranges. In the crystal, (Fig. 2), the adjacent molecules are connected via a pair of N—H···S and C—H···O (Table 1) hydrogen bonds, generating R²₂(8) and R²₂(10) graph-set motifs (Bernstein et al., 1995), respectively, resulting in a supramolecular [100] chain.

Experimental

A mixture of benzyl isothiocyanate (10 mmol) and 2-amino-5-methyl benzoic acid (10 mmol) in ethanol (30 ml) was heated under reflux in the presence of triethylamine (5 mmol) for 2 h. After cooling, the mixture was poured into ice/water. The resulting solid was filtered, washed with water and dried. Recrystallization from ethanol gave 3-benzyl-2,3-dihydro-6-methyl-2-thioxo-quinazoline-4(1H)-one as colorless crystals.