Ethyl 2-(5-chloro-3-methyl­sulfinyl-1-benzofuran-2-yl)acetate

The title compound, C₁₃H₁₃ClO₄S, was prepared by the oxidation of ethyl 2-(5-chloro-3-methyl­sulfanyl-1-benzofuran-2-yl)acetate using 3-chloro­perbenzoic acid. The O atom and the methyl group of the methyl­sulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment. The crystal structure is stabilized by inter­molecular aromatic π–π inter­actions, with a centroid–centroid distance of 3.609 (2) Å between the benzene rings of neighboring mol­ecules, and by two inter­molecular C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.033
• wR factor = 0.082
• Data-to-parameter ratio = 16.9

checkCIF/PLATON results

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Alert level C
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          4
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.72 Ratio

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   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
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S1. Comment

This work is related to preceding communications on the synthesis and structure of 2-benzofuranacetic acid derivatives, 2-(3-methylsulfanyl-5-phenyl-1-benzofuran-2-yl)acetic acid (Choi et al., 2007) and 2-(5-ethyl-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Seo et al., 2007). Herein we report the molecular and crystal structures of the title compound, ethyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.011 Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by π···π stacking interactions between adjacent benzene units. The Cg···Cgⁱⁱⁱ distance is 3.609 (2) Å (Cg is the centroid of the C2—C7 benzene ring; symmetry code as in Fig. 2). The molecular packing is further stabilized by two kind of intermolecular C—H···O hydrogen bonds (Table 1 and Fig. 2); one between the hydrogen on benzene ring and the oxygen of the S═O unit with a C3—H3···O2ⁱ, and a second between the hydrogen of methylene group and the oxygen of the S═O unit with a C9—H9A···O2ⁱⁱ, respectively.

Related literature

For crystal structures of isomers of the title compound, see: Choi et al. (2007); Seo et al. (2007).

S2. Experimental

3-Chloroperbenzoic acid (77%, 292 mg, 1.30 mmol) was added in small portions to a stirred solution of ethyl 2-(5-chloro-3-methylsulfanyl-1-benzofuran-2-yl)acetate (341 mg, 1.20 mmol) in dichloromethane (30 ml) at 273 K. After being stirred at room temperature for 2 h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (ethyl acetate) to afford the title compound as a colourless solid [yield 89%, m.p. 447–448 K; R_f = 0.70 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a dilute solution of the title compound in chloroform at room temperature.

S3. Refinement

All H atoms were positioned geometrically and refined using a riding model, with C—H = 0.95 Å for aromatic H atoms, 0.98 Å for methyl H atoms and 0.99 Å for methylene H atoms, respectively, and with U_iso(H) = 1.2U_eq(C) for aromatic and methylene H atoms and 1.5U_eq(C) for methyl H atoms. The highest peak in the difference map is 0.79 Å from Cl and the largest hole is 0.56 Å from S.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. The structure of the title molecule, showing displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. π···π interactions and intermolecular C—H···O hydrogen bonds (dotted lines) in the title compound. Cg denotes the benzene ring centroid. [Symmetry codes: (i) -x, 1 - y, -z; (ii) 1 - x, 1 - y, -z; (iii) -x, 1 - y, 1 - z.]

Ethyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate

Crystal data

C13H13ClO4S	Z = 2
Mr = 300.74	F(000) = 312
Triclinic, P1	Dx = 1.474 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.2750 (4) Å	Cell parameters from 3909 reflections
b = 9.3951 (4) Å	θ = 2.5–28.3°
c = 10.0755 (5) Å	µ = 0.44 mm^−1
α = 72.883 (1)°	T = 173 K
β = 78.837 (1)°	Block, colourless
γ = 65.280 (1)°	0.60 × 0.35 × 0.10 mm
V = 677.77 (6) Å^3

Data collection

Bruker SMART CCD diffractometer	2905 independent reflections
Radiation source: fine-focus sealed tube	2576 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.014
Detector resolution: 10.00 pixels mm^-1	θmax = 27.0°, θmin = 2.1°
φ and ω scans	h = −10→10
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	k = −11→11
Tmin = 0.840, Tmax = 0.961	l = −12→12
5881 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.082	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0312P)^2 + 0.3845P] where P = (Fo^2 + 2Fc^2)/3
2905 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.31 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S	0.22529 (6)	0.61850 (5)	0.03696 (4)	0.02606 (12)
Cl	−0.19460 (6)	0.21213 (6)	0.39767 (6)	0.03849 (14)
O1	0.33984 (14)	0.44917 (13)	0.42870 (11)	0.0215 (2)
O2	0.23374 (18)	0.48883 (17)	−0.02516 (13)	0.0361 (3)
O3	0.48845 (16)	0.87627 (14)	0.22936 (14)	0.0318 (3)
O4	0.23068 (17)	0.88156 (15)	0.18486 (15)	0.0375 (3)
C1	0.2349 (2)	0.53387 (18)	0.21755 (16)	0.0201 (3)
C2	0.1469 (2)	0.43132 (18)	0.30652 (16)	0.0199 (3)
C3	0.0171 (2)	0.37954 (19)	0.29186 (17)	0.0234 (3)
H3	−0.0354	0.4118	0.2065	0.028*
C4	−0.0307 (2)	0.27864 (19)	0.40868 (19)	0.0254 (3)
C5	0.0445 (2)	0.2272 (2)	0.53594 (18)	0.0270 (4)
H5	0.0082	0.1561	0.6122	0.032*
C6	0.1719 (2)	0.2801 (2)	0.55073 (17)	0.0249 (3)
H6	0.2242	0.2479	0.6362	0.030*
C7	0.2187 (2)	0.38205 (19)	0.43447 (17)	0.0208 (3)
C8	0.3477 (2)	0.54032 (18)	0.29495 (16)	0.0201 (3)
C9	0.4714 (2)	0.62598 (19)	0.26456 (17)	0.0223 (3)
H9A	0.5616	0.5891	0.1887	0.027*
H9B	0.5352	0.5962	0.3484	0.027*
C10	0.3791 (2)	0.8074 (2)	0.22247 (17)	0.0238 (3)
C11	0.4166 (3)	1.0527 (2)	0.1903 (3)	0.0416 (5)
H11A	0.3053	1.0965	0.2487	0.050*
H11B	0.3894	1.0926	0.0915	0.050*
C12	0.5542 (3)	1.1047 (3)	0.2121 (3)	0.0541 (6)
H12A	0.6640	1.0598	0.1545	0.065*
H12B	0.5788	1.0659	0.3105	0.065*
H12C	0.5104	1.2228	0.1857	0.065*
C13	−0.0024 (3)	0.7596 (2)	0.0363 (2)	0.0350 (4)
H13A	−0.0303	0.8187	−0.0597	0.052*
H13B	−0.0198	0.8359	0.0915	0.052*
H13C	−0.0816	0.7013	0.0769	0.052*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S	0.0269 (2)	0.0329 (2)	0.0187 (2)	−0.01322 (18)	−0.00490 (15)	−0.00219 (16)
Cl	0.0323 (2)	0.0335 (2)	0.0589 (3)	−0.0209 (2)	−0.0081 (2)	−0.0091 (2)
O1	0.0232 (6)	0.0228 (6)	0.0206 (5)	−0.0106 (5)	−0.0064 (4)	−0.0025 (4)
O2	0.0374 (7)	0.0467 (8)	0.0282 (7)	−0.0142 (6)	−0.0042 (5)	−0.0167 (6)
O3	0.0257 (6)	0.0204 (6)	0.0514 (8)	−0.0097 (5)	−0.0103 (6)	−0.0058 (5)
O4	0.0286 (7)	0.0264 (7)	0.0557 (9)	−0.0105 (5)	−0.0184 (6)	0.0022 (6)
C1	0.0211 (8)	0.0205 (8)	0.0187 (7)	−0.0076 (6)	−0.0036 (6)	−0.0040 (6)
C2	0.0201 (7)	0.0172 (7)	0.0220 (8)	−0.0053 (6)	−0.0032 (6)	−0.0061 (6)
C3	0.0224 (8)	0.0219 (8)	0.0280 (8)	−0.0071 (6)	−0.0052 (6)	−0.0089 (7)
C4	0.0212 (8)	0.0205 (8)	0.0388 (9)	−0.0097 (6)	−0.0022 (7)	−0.0108 (7)
C5	0.0265 (9)	0.0196 (8)	0.0318 (9)	−0.0089 (7)	0.0000 (7)	−0.0030 (7)
C6	0.0266 (8)	0.0224 (8)	0.0233 (8)	−0.0083 (7)	−0.0047 (6)	−0.0020 (6)
C7	0.0194 (7)	0.0191 (7)	0.0248 (8)	−0.0068 (6)	−0.0044 (6)	−0.0059 (6)
C8	0.0204 (8)	0.0181 (7)	0.0200 (7)	−0.0053 (6)	−0.0035 (6)	−0.0039 (6)
C9	0.0208 (8)	0.0227 (8)	0.0251 (8)	−0.0095 (6)	−0.0048 (6)	−0.0047 (6)
C10	0.0242 (8)	0.0250 (8)	0.0241 (8)	−0.0120 (7)	−0.0033 (6)	−0.0039 (6)
C11	0.0333 (10)	0.0201 (9)	0.0697 (15)	−0.0090 (8)	−0.0111 (10)	−0.0059 (9)
C12	0.0393 (12)	0.0249 (10)	0.101 (2)	−0.0145 (9)	−0.0108 (12)	−0.0126 (11)
C13	0.0330 (10)	0.0308 (10)	0.0361 (10)	−0.0059 (8)	−0.0155 (8)	−0.0023 (8)

Geometric parameters (Å, º)

S—O2	1.497 (1)	C5—H5	0.9500
S—C1	1.761 (2)	C6—C7	1.384 (2)
S—C13	1.794 (2)	C6—H6	0.9500
Cl—C4	1.747 (2)	C8—C9	1.488 (2)
O1—C8	1.374 (2)	C9—C10	1.510 (2)
O1—C7	1.375 (2)	C9—H9A	0.9900
O3—C10	1.335 (2)	C9—H9B	0.9900
O3—C11	1.462 (2)	C11—C12	1.486 (3)
O4—C10	1.203 (2)	C11—H11A	0.9900
C1—C8	1.356 (2)	C11—H11B	0.9900
C1—C2	1.445 (2)	C12—H12A	0.9800
C2—C7	1.394 (2)	C12—H12B	0.9800
C2—C3	1.397 (2)	C12—H12C	0.9800
C3—C4	1.385 (2)	C13—H13A	0.9800
C3—H3	0.9500	C13—H13B	0.9800
C4—C5	1.399 (2)	C13—H13C	0.9800
C5—C6	1.386 (2)
O2—S—C1	105.84 (8)	O1—C8—C9	115.8 (1)
O2—S—C13	106.39 (9)	C8—C9—C10	113.6 (1)
C1—S—C13	99.06 (8)	C8—C9—H9A	108.8
C8—O1—C7	106.4 (1)	C10—C9—H9A	108.8
C10—O3—C11	116.0 (1)	C8—C9—H9B	108.8
C8—C1—C2	107.4 (1)	C10—C9—H9B	108.8
C8—C1—S	123.8 (1)	H9A—C9—H9B	107.7
C2—C1—S	128.4 (1)	O4—C10—O3	124.0 (2)
C7—C2—C3	119.7 (1)	O4—C10—C9	126.0 (2)
C7—C2—C1	104.5 (1)	O3—C10—C9	110.0 (1)
C3—C2—C1	135.8 (1)	O3—C11—C12	107.5 (2)
C4—C3—C2	116.3 (2)	O3—C11—H11A	110.2
C4—C3—H3	121.8	C12—C11—H11A	110.2
C2—C3—H3	121.8	O3—C11—H11B	110.2
C3—C4—C5	123.7 (2)	C12—C11—H11B	110.2
C3—C4—Cl	118.5 (1)	H11A—C11—H11B	108.5
C5—C4—Cl	117.9 (1)	C11—C12—H12A	109.5
C6—C5—C4	120.0 (2)	C11—C12—H12B	109.5
C6—C5—H5	120.0	H12A—C12—H12B	109.5
C4—C5—H5	120.0	C11—C12—H12C	109.5
C7—C6—C5	116.5 (2)	H12A—C12—H12C	109.5
C7—C6—H6	121.8	H12B—C12—H12C	109.5
C5—C6—H6	121.8	S—C13—H13A	109.5
O1—C7—C6	125.3 (1)	S—C13—H13B	109.5
O1—C7—C2	110.8 (1)	H13A—C13—H13B	109.5
C6—C7—C2	123.9 (2)	S—C13—H13C	109.5
C1—C8—O1	110.9 (1)	H13A—C13—H13C	109.5
C1—C8—C9	133.3 (2)	H13B—C13—H13C	109.5
O2—S—C1—C8	130.55 (14)	C5—C6—C7—C2	−0.6 (2)
C13—S—C1—C8	−119.43 (15)	C3—C2—C7—O1	−178.31 (13)
O2—S—C1—C2	−41.17 (16)	C1—C2—C7—O1	0.90 (17)
C13—S—C1—C2	68.84 (16)	C3—C2—C7—C6	1.3 (2)
C8—C1—C2—C7	−0.53 (17)	C1—C2—C7—C6	−179.46 (15)
S—C1—C2—C7	172.27 (12)	C2—C1—C8—O1	−0.02 (18)
C8—C1—C2—C3	178.49 (18)	S—C1—C8—O1	−173.23 (11)
S—C1—C2—C3	−8.7 (3)	C2—C1—C8—C9	−178.93 (16)
C7—C2—C3—C4	−0.7 (2)	S—C1—C8—C9	7.9 (3)
C1—C2—C3—C4	−179.58 (17)	C7—O1—C8—C1	0.58 (17)
C2—C3—C4—C5	−0.6 (2)	C7—O1—C8—C9	179.70 (13)
C2—C3—C4—Cl	179.09 (12)	C1—C8—C9—C10	60.8 (2)
C3—C4—C5—C6	1.3 (3)	O1—C8—C9—C10	−118.03 (15)
Cl—C4—C5—C6	−178.40 (13)	C11—O3—C10—O4	1.2 (3)
C4—C5—C6—C7	−0.6 (2)	C11—O3—C10—C9	179.60 (16)
C8—O1—C7—C6	179.43 (15)	C8—C9—C10—O4	−16.3 (3)
C8—O1—C7—C2	−0.93 (17)	C8—C9—C10—O3	165.26 (14)
C5—C6—C7—O1	178.95 (15)	C10—O3—C11—C12	177.06 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2^i	0.95	2.40	3.334 (2)	166
C9—H9A···O2^ii	0.99	2.17	3.160 (2)	178

Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y+1, −z.