Absolute configuration of (1S,2S)-3-methyl-2-phenyl-2,3-dihydro­thia­zolo[2,3-b]quinazolin-5-one

Mostafa M Ghorab; Mansour S Al-Said; Maged S Abdel-Kader; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S160053681200832X

. 2012 Mar 3;68(Pt 4):o927–o928. doi: 10.1107/S160053681200832X

Absolute configuration of (1S,2S)-3-methyl-2-phenyl-2,3-dihydrothiazolo[2,3-b]quinazolin-5-one

Mostafa M Ghorab ^a, Mansour S Al-Said ^a, Maged S Abdel-Kader ^b, Madhukar Hemamalini ^c, Hoong-Kun Fun ^c,^*,^‡

PMCID: PMC3343911 PMID: 22589992

Abstract

The absolute structure of the molecule in the crystal of the title compound, C₁₇H₁₄N₂OS, was determined by the refinement of the Flack parameter to 0.0 (2) based on 1011 Friedel pairs. The quinazoline ring is essentially planar, with a maximum deviation of 0.037 (2) Å. The thiazole ring is distorted from planarity [maximum deviation = 0.168 (2) Å] and adopts a slightly twisted envelope conformation, with the C atom as the flap atom. The central thiazole ring makes dihedral angles of 7.01 (8) and 76.80 (10)° with the quinazoline and phenyl rings, respectively. The corresponding angle between the quinazoline and phenyl rings is 3.74 (9)°. In the crystal, there are no classical hydrogen bonds but stabilization is provided by weak C—H⋯π interactions, involving the centroids of the phenyl rings.

Related literature

For details and applications of quinazoline derivatives, see: Ghorab et al. (2010a ▶,b ▶,c ▶). For related crystal structures, see: Al-Salahi et al. (2012 ▶); Priya et al. (2011 ▶); Liu et al. (2010 ▶). For ring conformations, see: Cremer & Pople (1975 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₇H₁₄N₂OS
M _r = 294.36
Orthorhombic,
a = 8.4865 (1) Å
b = 10.0846 (2) Å
c = 16.8290 (3) Å
V = 1440.28 (4) Å³
Z = 4
Cu Kα radiation
μ = 1.99 mm⁻¹
T = 296 K
0.96 × 0.64 × 0.51 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.251, T _max = 0.431
8654 measured reflections
2637 independent reflections
2521 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.109
S = 1.08
2637 reflections
192 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.23 e Å⁻³
Absolute structure: Flack (1983 ▶), with 1011 Friedel pairs
Flack parameter: 0.00 (2)

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/S160053681200832X/nk2145sup1.cif

e-68-0o927-sup1.cif^{(25KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681200832X/nk2145Isup2.hkl

e-68-0o927-Isup2.hkl^{(126.9KB, hkl)}

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

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

Cg3 and Cg4 are the centroids of the C4–C9 and C11–C16 phenyl rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2B⋯Cg3ⁱ	0.98	2.91	3.824 (2)	155
C6—H6A⋯Cg4ⁱⁱ	0.93	2.81	3.637 (3)	146

Open in a new tab

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

Acknowledgments

MMG, MSA and MSA are grateful for sponsorship of the Research Center, College of Pharmacy, and the Deanship of Scientific Research, King Saud University, Riyadh, Saudia Arabia. 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 derivatives are well known as biologically active compounds. Consequently, quinazolines have been intensively studied for their interesting pharmacological properties such as anticancer activity (Ghorab et al., 2010a,b,c). The crystal structures of 2-Ethoxy-5-methylbis[1,2,4]triazolo[1,5-a:4',3'-c] quinazoline (Al-Salahi et al., 2012), 3-(4-Chlorophenyl)quinazolin-4(3H)-one (Priya et al., 2011) and 2-Anilino-3-(2-hydroxyphenyl)quinazolin-4(3H)-one methanol monosolvate (Liu et al., 2010) have been reported in the literature. Herein, we report the crystal structure of title compound (I).

The asymmetric unit of the title compound is shown in Fig. 1. The quinazoline (N1,N2/C3–C10) ring is essentially planar, with a maximum deviation of 0.037 (2) Å for atom C8. The thiazole (S1/N2/C7–C9) rings adopt an envelope conformation with the C2 (0.168 (2) Å) atom as the flap atom and with puckering parameter, Q = 0.2724 (19) Å and θ = 226.7 (4)° (Cremer & Pople, 1975). The central thiazole (S1/N1/C1–C2,C10) ring makes dihedral angles of 7.01 (8)° and 76.80 (10)° with the quinazoline (N1,N2/C3–C10) and phenyl (C11–C16) rings, respectively. The corresponding angle between the quinazoline (N1,N2/C3–C10) and phenyl (C11–C16) rings is 73.74 (9)°. The bond lengths (Allen et al., 1987) and angles are within normal ranges.

The absolute configuration of the molecule were determined by the refinement of the Flack parameter to 0.0 (2). There are two chiral centres in the molecule. From the structure presented, these centers exhibit the following chiralities: C1 = S and C2 = S.

In the crystal structure (Fig. 2), there are no classical hydrogen bonds but stabilization is provided by weak C—H···π interactions (Table 1) involving the centroids of the (C4–C9) and (C11–C16) phenyl rings.

Experimental

A mixture of 2-isothiocyanatobenzoate (1.93 g, 0.01 mole) and 2-amino-1-phenylpropan-1-ol (1.51 g, 0.01 mole) in dry dimethylformamide (30 ml) containing a catalytic amount of triethylamine was refluxed for 6 h. The solid obtained was recrystallized from ethanol to give the title thiazoloquinazline derivative compound. Single crystals suitable for X-ray structural analysis were obtained by slow evaporation from ethanol at room temperature.