2-(1,3-Benzoxazol-2-ylsulfan­yl)-1-phenyl­ethanone

Hossein Loghmani-Khouzani; Dariush Hajiheidari; Ward T Robinson; Noorsaadah Abdul Rahman; Reza Kia

doi:10.1107/S1600536809033960

. 2009 Aug 29;65(Pt 9):o2287. doi: 10.1107/S1600536809033960

2-(1,3-Benzoxazol-2-ylsulfanyl)-1-phenylethanone

Hossein Loghmani-Khouzani ^a, Dariush Hajiheidari ^a, Ward T Robinson ^b, Noorsaadah Abdul Rahman ^b, Reza Kia ^c,^*,^‡

PMCID: PMC2970099 PMID: 21577679

Abstract

In the title compound, C₁₅H₁₁NO₂S, a new thio-benzoxazole derivative, the dihedral angle between the benzoxazole ring and the phenyl ring is 9.91 (9)°. An interesting feature of the crystal structure is the short C⋯S [3.4858 (17) Å] contact, which is shorter than the sum of the van der Waals radii of these atoms. In the crystal structure, molecules are linked together by zigzag intermolecular C—H⋯N interactions into a column along the a axis. The crystal structure is further stabilized by intermolecular π–π interactions [centroid–centroid = 3.8048 (10) Å].

Related literature

For applications of 2-(benzo[d]oxazol-2-ylthio)-1-phenylethanone and β-keto-sulfones in organic synthesis, see: Marco et al. (1995 ▶); Fuju et al. (1988 ▶); Ni et al. (2006 ▶). For uses of haloalkyl sulfones, see: Grossert et al. (1984 ▶); Oishi et al. (1988 ▶); Antane et al. (2004 ▶). For their biological activity, see: Padmavathi et al. (2008 ▶). For bond-length data, see: Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₅H₁₁NO₂S
M _r = 269.31
Orthorhombic,
a = 4.8580 (2) Å
b = 14.0780 (5) Å
c = 18.6840 (7) Å
V = 1277.82 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.25 mm⁻¹
T = 296 K
0.50 × 0.10 × 0.10 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.886, T _max = 0.976
13902 measured reflections
3659 independent reflections
3175 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.093
S = 1.04
3659 reflections
172 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ▶), 1514 Friedel pairs
Flack parameter: 0.07 (7)

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2004 ▶); program(s) used to refine structure: SHELXTL (Sheldrick, 2008 ▶); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809033960/at2859sup1.cif

e-65-o2287-sup1.cif^{(17.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809033960/at2859Isup2.hkl

e-65-o2287-Isup2.hkl^{(179.4KB, 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
C5—H5A⋯N1ⁱ	0.93	2.56	3.395 (2)	149

Open in a new tab

Symmetry code: (i) Inline graphic .

Acknowledgments

We thank the University of Isfahan and the University of Malaya for supporting this work.

supplementary crystallographic information

Comment

2-(Benzo[d]oxazol-2-ylthio)-1-phenylethanone is of great importance in organic synthesis and β-Keto-sulfones are a very important group of intermediates as they are precursors for Michael and Knoevenagel reactions and are used in the preparation of acetylenes, allenes, chalcones, vinyl sulfones, polyfunctionalized 4H-pyrans and ketones (Marco et al., 1995; Fuju et al., 1988; Ni et al., 2006). In addition, β-keto-sulfones can be converted into optically active β-hydroxy-sulfones, halomethyl sulfones and dihalomethyl sulfones. Halomethyl sulfones and dihalomethyl sulfones are very good α-carbanion stabilizing substituents and precursors for the preparation of alkenes, aziridines, epoxides, and β-hydroxy-sulfones. Haloalkyl sulfones are useful in preventing aquatic organisms from attaching to fishing nets and ship hulls (Grossert et al., 1984; Oishi et al., 1988; Antane et al., 2004). They also possess other biological properties such as herbicidal, bactericidal antifungal and insecticidal. Recently sulfone-linked heterocycles were prepared and have been showed antimicrobial activity (Padmavathi et al., 2008). We prepared this compound as a precursor for synthesis of gem-difluoromethylene- containing heterocycle.

In the molecule of the title compound, (Fig. 1), a new thio-benzoxazole derivative, the dihedral angle between the benzoxazole ring and the phenyl ring is 9.91 (9)°. The interesting feature of the crystal structure is the short C6···S1ⁱ [3.4858 (17) Å; (i) -1 + x, y, z] contact which is shorter than the sum of the van der Waals radii of these atoms. In the crystal structure, the molecules are linked together by a zig-zag intermolecular C—H···N interactions (Table 1) which packed into a column along the a axis (Fig. 2). The crystal structure is further stabilized by the intramolecular π–π interactions [Cg1···Cg2ⁱ = 3.8048 (10) Å].

Experimental

Sodium carbonate (4.5 mmol) was added to a stirred solution of 2-mercaptobenzoxazole (3 mmol) in ethanol (15 mL) and water (15 mL) and stirred in room temperature for 30 min. α-Bromoacetophenone (3 mmol) was added to the reaction mixture and stirring was continued for 1h. The reaction was monitored by TLC and after 60 min. showed the complete disappearance of starting material. The reaction mixture was poured into 100 mL of 1M HCl containing 50 g of crushed ice. The product was filtered under vacuum and filtrate washed with 10 mL ice-cold ethanol and 10 mL water. Recrystalization from petrol ether and filtration gave the title compound. m.p.: 397-398 K; ¹H NMR (400 MHz; CDCl₃): δ 7.86-7.21 (m, 9H), 4.58 (s, 2H). ¹³C NMR (126 MHz; CDCl₃): δ 194.1 (C═O), 164.3, 148.9, 140.8, 136.1, 132.6, 128.0, 127.8, 124.1, 122.9, 118.3, 109.6, 37.3. IR (KBr, cm^-1 ): 3027, 2581, 1671 (C═O), 1593, 1492, 1447, 1382, 1326, 1291, 1230, 1182, 1025, 993, 738. Analysis calculated for C₁₅H₁₁NO₂S: C 66.89, H 4.12, N 5.20%. Found: C 66.96, H 4.06, N 5.17%.