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

The title compound, C₁₃H₁₃BrO₄S, was prepared by the oxidation of ethyl 2-(5-bromo-3-methyl­sulfanyl-1-benzofuran-2-yl)acetate using 3-chloro­perbenzoic acid. The O atom and methyl group of the methylsulfinyl substituent lie on opposite sides of the plane of the benzofuran moiety. The crystal structure is stabilized by inter­molecular π–π inter­actions [centroid-to-centroid separation = 3.592 (2) Å], as well as by C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.022
• wR factor = 0.059
• Data-to-parameter ratio = 17.2

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 =          3
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.63 Ratio

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   0 ALERT level B = Potentially serious problem
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   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
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S1. Comment

As part of our on-going studies on the synthesis and structure of 2-benzofuranacetic acid derivatives, we have recently described the crystal structures of ethyl [5-(4-hydroxyphenyl)-3-methylsulfanyl-1-benzofuran-2-yl]acetate (Choi et al., 2006) and 2-(3-methyllsulfanyl-5-phenyl-1-benzofuran-2-yl)acetic acid (Choi et al., 2007). Herein, we report the molecular and crystal structure of the title compound, ethyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (I, Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.010 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···Cg^iv distance is 3.592 (2) Å (Cg is the centroid of the C2–C7 ring; symmetry code as in Fig. 2). The molecular packing is further stabilized by C—H···O interactions (Table 1 and Fig. 2): one between a benzene-H and the S═O unit, i.e. C3—H3···O2ⁱ, a second between a methylene-H and the S═O unit, i.e. C9—H9B···O2ⁱⁱ, and a third between the second methylene-H the furan-O, i.e. C9—H9A···O1ⁱⁱⁱ.

Related literature

For the crystal structures of isomers of the title compound, see: Choi et al. (2006, 2007).

S2. Experimental

3-Chloroperbenzoic acid (77%, 359 mg, 1.60 mmol) was added in small portions to a stirred solution of ethyl 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetate (494 mg, 1.50 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 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 (I) as a colorless solid [yield 86%, m.p. 453–454 K; R_f = 0.73 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a dilute chloroform solution of (I) held at room temperature.

S3. Refinement

All the H atoms were included in the riding-model approximation, with C—H = 0.95–0.99, and with U_iso(H) = 1.2 or 1.5U_eq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; 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.

Figures

	Fig. 1. The molecular structure of (I), showing displacement ellipsoides drawn at the 50% probability level.
	Fig. 2. π–π Interactions and C—H···O interactions (dotted lines) in (I). Cg denotes the ring centroid. [Symmetry codes: (i) 2 - x, -y, 1 - z; (ii) 1 - x, -y, 1 - z; (iii) 1 - x, -y, -z; (iv) 2 - x, -y, -z.]

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

Crystal data

C13H13BrO4S	Z = 2
Mr = 345.20	F(000) = 348
Triclinic, P1	Dx = 1.666 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.3557 (4) Å	Cell parameters from 4506 reflections
b = 9.5625 (5) Å	θ = 2.2–28.3°
c = 10.0192 (5) Å	µ = 3.14 mm^−1
α = 71.644 (1)°	T = 173 K
β = 78.619 (1)°	Block, colourless
γ = 65.304 (1)°	0.40 × 0.40 × 0.20 mm
V = 688.31 (6) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	2961 independent reflections
Radiation source: fine-focus sealed tube	2772 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.016
Detector resolution: 10.0 pixels mm^-1	θmax = 27.0°, θmin = 2.2°
φ and ω scans	h = −10→10
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	k = −12→12
Tmin = 0.321, Tmax = 0.541	l = −12→12
5994 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)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.059	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.031P)^2 + 0.3245P] where P = (Fo^2 + 2Fc^2)/3
2961 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.38 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
Br	1.19929 (2)	0.29496 (2)	0.09731 (2)	0.03275 (7)
S	0.77219 (6)	−0.11607 (5)	0.46784 (4)	0.02467 (10)
O1	0.66177 (15)	0.04723 (13)	0.06926 (11)	0.0211 (2)
O2	0.76708 (18)	0.01229 (17)	0.52618 (13)	0.0339 (3)
O3	0.51765 (17)	−0.37582 (15)	0.27271 (15)	0.0303 (3)
O4	0.76958 (18)	−0.37966 (16)	0.32289 (16)	0.0359 (3)
C1	0.7622 (2)	−0.03343 (19)	0.28450 (16)	0.0198 (3)
C2	0.8492 (2)	0.06848 (19)	0.19260 (16)	0.0197 (3)
C3	0.9766 (2)	0.12143 (19)	0.20606 (17)	0.0219 (3)
H3	1.0273	0.0910	0.2928	0.026*
C4	1.0248 (2)	0.2206 (2)	0.08611 (18)	0.0231 (3)
C5	0.9530 (2)	0.2688 (2)	−0.04359 (18)	0.0246 (3)
H5	0.9900	0.3382	−0.1221	0.030*
C6	0.8282 (2)	0.2155 (2)	−0.05775 (17)	0.0236 (3)
H6	0.7778	0.2461	−0.1447	0.028*
C7	0.7807 (2)	0.11484 (19)	0.06213 (17)	0.0200 (3)
C8	0.6524 (2)	−0.04197 (19)	0.20650 (16)	0.0199 (3)
C9	0.5307 (2)	−0.1276 (2)	0.23858 (17)	0.0223 (3)
H9A	0.4667	−0.0971	0.1541	0.027*
H9B	0.4421	−0.0931	0.3154	0.027*
C10	0.6233 (2)	−0.3068 (2)	0.28198 (17)	0.0232 (3)
C11	0.5906 (3)	−0.5504 (2)	0.3129 (3)	0.0385 (5)
H11A	0.6164	−0.5916	0.4133	0.046*
H11B	0.7015	−0.5917	0.2548	0.046*
C12	0.4550 (3)	−0.6019 (3)	0.2887 (3)	0.0517 (6)
H12A	0.4308	−0.5606	0.1890	0.062*
H12B	0.3459	−0.5604	0.3468	0.062*
H12C	0.4993	−0.7187	0.3146	0.062*
C13	0.9969 (3)	−0.2565 (2)	0.4702 (2)	0.0339 (4)
H13A	1.0248	−0.3146	0.5679	0.051*
H13B	1.0760	−0.1996	0.4271	0.051*
H13C	1.0125	−0.3321	0.4169	0.051*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br	0.02947 (11)	0.02946 (11)	0.04696 (12)	−0.01799 (8)	−0.00698 (8)	−0.00823 (8)
S	0.0261 (2)	0.0304 (2)	0.01890 (18)	−0.01329 (17)	−0.00469 (15)	−0.00297 (16)
O1	0.0224 (6)	0.0224 (6)	0.0211 (5)	−0.0103 (5)	−0.0062 (4)	−0.0038 (4)
O2	0.0364 (7)	0.0424 (8)	0.0270 (6)	−0.0134 (6)	−0.0042 (5)	−0.0160 (6)
O3	0.0256 (6)	0.0204 (6)	0.0472 (8)	−0.0100 (5)	−0.0100 (5)	−0.0059 (5)
O4	0.0288 (7)	0.0269 (7)	0.0513 (8)	−0.0115 (6)	−0.0174 (6)	0.0009 (6)
C1	0.0208 (7)	0.0193 (8)	0.0194 (7)	−0.0071 (6)	−0.0039 (6)	−0.0043 (6)
C2	0.0201 (7)	0.0176 (7)	0.0217 (7)	−0.0059 (6)	−0.0032 (6)	−0.0065 (6)
C3	0.0220 (8)	0.0210 (8)	0.0256 (8)	−0.0076 (6)	−0.0051 (6)	−0.0086 (6)
C4	0.0193 (7)	0.0199 (8)	0.0337 (9)	−0.0087 (6)	−0.0027 (6)	−0.0099 (7)
C5	0.0248 (8)	0.0181 (8)	0.0278 (8)	−0.0071 (7)	−0.0015 (7)	−0.0036 (6)
C6	0.0247 (8)	0.0212 (8)	0.0232 (8)	−0.0073 (7)	−0.0057 (6)	−0.0032 (6)
C7	0.0187 (7)	0.0183 (7)	0.0240 (7)	−0.0059 (6)	−0.0049 (6)	−0.0066 (6)
C8	0.0201 (7)	0.0177 (7)	0.0209 (7)	−0.0056 (6)	−0.0039 (6)	−0.0046 (6)
C9	0.0210 (8)	0.0231 (8)	0.0253 (8)	−0.0101 (6)	−0.0051 (6)	−0.0051 (6)
C10	0.0234 (8)	0.0251 (8)	0.0232 (8)	−0.0114 (7)	−0.0038 (6)	−0.0049 (6)
C11	0.0330 (10)	0.0197 (9)	0.0622 (13)	−0.0098 (8)	−0.0116 (9)	−0.0055 (9)
C12	0.0407 (12)	0.0253 (10)	0.0935 (19)	−0.0149 (9)	−0.0159 (12)	−0.0114 (11)
C13	0.0318 (10)	0.0305 (10)	0.0346 (10)	−0.0057 (8)	−0.0145 (8)	−0.0034 (8)

Geometric parameters (Å, º)

Br—C4	1.904 (2)	C5—H5	0.9500
S—O2	1.500 (1)	C6—C7	1.389 (2)
S—C1	1.760 (2)	C6—H6	0.9500
S—C13	1.794 (2)	C8—C9	1.486 (2)
O1—C7	1.375 (2)	C9—C10	1.510 (2)
O1—C8	1.378 (2)	C9—H9A	0.9900
O3—C10	1.334 (2)	C9—H9B	0.9900
O3—C11	1.464 (2)	C11—C12	1.495 (3)
O4—C10	1.206 (2)	C11—H11A	0.9900
C1—C8	1.358 (2)	C11—H11B	0.9900
C1—C2	1.445 (2)	C12—H12A	0.9800
C2—C7	1.397 (2)	C12—H12B	0.9800
C2—C3	1.399 (2)	C12—H12C	0.9800
C3—C4	1.384 (2)	C13—H13A	0.9800
C3—H3	0.9500	C13—H13B	0.9800
C4—C5	1.400 (2)	C13—H13C	0.9800
C5—C6	1.383 (2)
O2—S—C1	105.74 (8)	O1—C8—C9	115.7 (1)
O2—S—C13	106.19 (9)	C8—C9—C10	113.5 (1)
C1—S—C13	98.98 (8)	C8—C9—H9A	108.9
C7—O1—C8	106.3 (1)	C10—C9—H9A	108.9
C10—O3—C11	116.1 (1)	C8—C9—H9B	108.9
C8—C1—C2	107.4 (1)	C10—C9—H9B	108.9
C8—C1—S	124.3 (1)	H9A—C9—H9B	107.7
C2—C1—S	128.0 (1)	O4—C10—O3	123.8 (2)
C7—C2—C3	119.6 (2)	O4—C10—C9	125.9 (2)
C7—C2—C1	104.6 (1)	O3—C10—C9	110.2 (1)
C3—C2—C1	135.9 (2)	O3—C11—C12	107.2 (2)
C4—C3—C2	116.4 (2)	O3—C11—H11A	110.3
C4—C3—H3	121.8	C12—C11—H11A	110.3
C2—C3—H3	121.8	O3—C11—H11B	110.3
C3—C4—C5	123.6 (2)	C12—C11—H11B	110.3
C3—C4—Br	118.3 (1)	H11A—C11—H11B	108.5
C5—C4—Br	118.0 (1)	C11—C12—H12A	109.5
C6—C5—C4	120.2 (2)	C11—C12—H12B	109.5
C6—C5—H5	119.9	H12A—C12—H12B	109.5
C4—C5—H5	119.9	C11—C12—H12C	109.5
C5—C6—C7	116.3 (2)	H12A—C12—H12C	109.5
C5—C6—H6	121.8	H12B—C12—H12C	109.5
C7—C6—H6	121.8	S—C13—H13A	109.5
O1—C7—C6	125.3 (1)	S—C13—H13B	109.5
O1—C7—C2	110.9 (1)	H13A—C13—H13B	109.5
C6—C7—C2	123.9 (2)	S—C13—H13C	109.5
C1—C8—O1	110.8 (1)	H13A—C13—H13C	109.5
C1—C8—C9	133.5 (2)	H13B—C13—H13C	109.5
O2—S—C1—C8	−132.39 (15)	C5—C6—C7—C2	1.0 (2)
C13—S—C1—C8	117.86 (15)	C3—C2—C7—O1	178.24 (14)
O2—S—C1—C2	40.01 (17)	C1—C2—C7—O1	−0.64 (17)
C13—S—C1—C2	−69.74 (16)	C3—C2—C7—C6	−1.6 (2)
C8—C1—C2—C7	0.28 (18)	C1—C2—C7—C6	179.53 (15)
S—C1—C2—C7	−173.14 (12)	C2—C1—C8—O1	0.17 (18)
C8—C1—C2—C3	−178.31 (18)	S—C1—C8—O1	173.89 (11)
S—C1—C2—C3	8.3 (3)	C2—C1—C8—C9	179.06 (17)
C7—C2—C3—C4	0.9 (2)	S—C1—C8—C9	−7.2 (3)
C1—C2—C3—C4	179.38 (17)	C7—O1—C8—C1	−0.55 (17)
C2—C3—C4—C5	0.2 (2)	C7—O1—C8—C9	−179.66 (13)
C2—C3—C4—Br	−179.40 (12)	C1—C8—C9—C10	−62.5 (2)
C3—C4—C5—C6	−0.8 (3)	O1—C8—C9—C10	116.37 (15)
Br—C4—C5—C6	178.78 (13)	C11—O3—C10—O4	−1.3 (3)
C4—C5—C6—C7	0.2 (2)	C11—O3—C10—C9	−179.58 (16)
C8—O1—C7—C6	−179.42 (15)	C8—C9—C10—O4	18.2 (2)
C8—O1—C7—C2	0.74 (17)	C8—C9—C10—O3	−163.55 (14)
C5—C6—C7—O1	−178.85 (15)	C10—O3—C11—C12	−177.56 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2^i	0.95	2.43	3.352 (2)	164
C9—H9B···O2^ii	0.99	2.17	3.161 (2)	176
C9—H9A···O1^iii	0.99	2.50	3.4816 (19)	173

Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+1, −y, −z+1; (iii) −x+1, −y, −z.