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

The title compound, C₁₂H₁₁ClO₄S, was prepared by the oxidation of methyl 2-(5-chloro-3-methyl­sulfanyl-1-benzofuran-2-yl)acetate with 3-chloro­peroxy­benzoic 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 aromatic π–π inter­actions between the benzene rings of neighbouring mol­ecules [centroid-to-centroid distance = 3.809 (2) Å], and by C—H...π inter­actions between a methyl H atom and the furan ring of an adjacent mol­ecule. In addition, the crystal structure exhibits inter­molecular C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.035
• wR factor = 0.101
• Data-to-parameter ratio = 14.9

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   298.000
            Value of melting point given =     0.000
SHFSU01_ALERT_2_C  Test not performed. _refine_ls_shift/su_max and
            _refine_ls_shift/esd_max not present.
            Absolute value of the parameter shift to su ratio given   0.001
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.57 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.09 Ratio
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C10
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT180_ALERT_4_C Check Cell Rounding: # of Values Ending with 0 =          4

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Benzofuran derivatives occur widely in natural products and show a variety of interesting pharmacological activities such as antimicrobial, fungicidal, insecticidal and antioxidant properties (Ward, 1999). As a part of our ongoing studies on the synthesis and structure of 2-(3-methylsulfinyl-1-benzofuran-2-yl)acetic acid analogues, the crystal structure of ethyl 2-(5-chloro-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2007) and methyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008) have been described in the literature. Here we report the crystal structure of the title compound, methyl 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 (2) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by aromatic π–π stacking interactions between the benzene rings of adjacent molecules. The Cg2···Cg2ⁱⁱ distance is 3.809 (2) Å (Cg2 is the centroid of the C2–C7 benzene ring; symmetry code as in Fig. 2). The molecular packing is further stabilized by C—H···π interactions between a methyl H atom and the furan ring of the benzofuran uint, with a C11—H11C···Cg1ⁱ separation of 2.92 Å (Fig. 2 and Table 1; Cg1 is the centroid of the C1/C2/C7/O1/C8 furan ring). Additionally, intermolecular C—H···O hydrogen bonds in the structure were observed (Table 1).

Related literature

For details of the pharmacological activities of benzofuran compounds, see: Ward (1999). For the crystal structures of similar 2-(3-methylsulfinyl-1-benzofuran-2-yl)acetic acid derivatives, see: Choi et al. (2007, 2008).

S2. Experimental

77% 3-Chloroperoxybenzoic acid (292 mg, 1.3 mmol) was added in small portions to a stirred solution of methyl 2-(5-chloro-3-methylsulfanyl-1-benzofuran-2-yl)acetate (325 mg, 1.2 mmol) in dichloromethane (40 ml) at 273 K. After being stirred for 3 h at room temperature, 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 colorless solid [yield 77%, m.p. 415–416 K; R_f = 0.72 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in benzene at room temperature. Spectroscopic analysis: ¹H NMR (CDCl₃, 400 MHz) δ 3.07 (s, 3H), 3.75 (s, 3H), 4.05 (s, 2H), 7.34 (dd, J = 8.76 Hz and J = 1.80 Hz, 1H), 7.44 (d, J = 8.80 Hz, 1H), 7.90 (d, J = 1.80 Hz, 1H); EI–MS 288 [M+2], 286[M⁺].

S3. Refinement

All H atoms were geometrically positioned and refined using a riding model, with C—H = 0.93 Å (aromatic), 0.97 Å (methylene), and 0.96 Å (methyl) H atoms, respectively, and with U_iso(H) = 1.2Ueq(C) (aromatic & methylene), and 1.5Ueq(C) (methyl) H atoms.

Computing details

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level.
	Fig. 2. π–π and C—H···π interactions (dotted lines) in the title compound. Cg denotes the ring centroid. [Symmetry code: (i) x, y + 1, z; (ii) -x, -y + 1, -z + 2; (iii) x, y - 1, z.]

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

Crystal data

C12H11ClO4S	Z = 2
Mr = 286.72	F(000) = 296
Triclinic, P1	Dx = 1.459 Mg m^−3
Hall symbol: -P_1	Melting point = 415–416 K
a = 7.8910 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.9416 (6) Å	Cell parameters from 2313 reflections
c = 10.4048 (7) Å	θ = 2.8–28.2°
α = 73.774 (1)°	µ = 0.46 mm^−1
β = 78.743 (1)°	T = 298 K
γ = 68.559 (1)°	Block, colourless
V = 652.55 (7) Å^3	0.40 × 0.40 × 0.20 mm

Data collection

Bruker SMART CCD diffractometer	2525 independent reflections
Radiation source: fine-focus sealed tube	2123 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.012
Detector resolution: 10.0 pixels mm^-1	θmax = 26.0°, θmin = 2.5°
ϕ and ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Sheldrick, 1999)	k = −11→7
Tmin = 0.827, Tmax = 0.907	l = −12→12
3753 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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.101	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0497P)^2 + 0.2053P] where P = (Fo^2 + 2Fc^2)/3
2525 reflections	(Δ/σ)max < 0.001
169 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.25 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
Cl	−0.22541 (8)	0.20560 (7)	0.87139 (8)	0.0834 (2)
S	0.23616 (7)	0.63233 (7)	0.54121 (5)	0.05176 (17)
O1	0.33659 (17)	0.45642 (16)	0.92043 (12)	0.0468 (3)
O2	0.5278 (2)	0.89402 (19)	0.72451 (19)	0.0728 (5)
O3	0.2521 (2)	0.9006 (2)	0.69823 (19)	0.0748 (5)
O4	0.2462 (2)	0.4995 (2)	0.47609 (15)	0.0688 (4)
C1	0.2400 (2)	0.5423 (2)	0.71481 (17)	0.0429 (4)
C2	0.1418 (2)	0.4347 (2)	0.79676 (17)	0.0424 (4)
C3	0.0067 (3)	0.3789 (2)	0.7780 (2)	0.0489 (4)
H3	−0.040 (3)	0.409 (3)	0.694 (2)	0.053 (6)*
C4	−0.0519 (3)	0.2747 (2)	0.8878 (2)	0.0555 (5)
C5	0.0180 (3)	0.2229 (3)	1.0116 (2)	0.0596 (5)
H5	−0.0254	0.1511	1.0818	0.072*
C6	0.1517 (3)	0.2778 (2)	1.0307 (2)	0.0556 (5)
H6	0.2007	0.2447	1.1124	0.067*
C7	0.2087 (2)	0.3845 (2)	0.92181 (19)	0.0450 (4)
C8	0.3537 (2)	0.5507 (2)	0.79220 (18)	0.0433 (4)
C9	0.4870 (3)	0.6396 (2)	0.7667 (2)	0.0494 (4)
H9A	0.5801	0.6024	0.6959	0.059*
H9B	0.5470	0.6105	0.8475	0.059*
C10	0.4045 (3)	0.8245 (3)	0.72678 (19)	0.0489 (4)
C11	0.4682 (5)	1.0733 (3)	0.6855 (4)	0.1092 (12)
H11A	0.4158	1.1104	0.6016	0.164*
H11B	0.5713	1.1098	0.6754	0.164*
H11C	0.3782	1.1180	0.7537	0.164*
C12	0.0024 (3)	0.7661 (3)	0.5437 (2)	0.0661 (6)
H12A	−0.0223	0.8297	0.4543	0.099*
H12B	−0.0183	0.8390	0.6018	0.099*
H12C	−0.0772	0.7011	0.5764	0.099*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl	0.0594 (4)	0.0550 (3)	0.1360 (6)	−0.0274 (3)	−0.0214 (4)	−0.0029 (4)
S	0.0541 (3)	0.0652 (3)	0.0390 (3)	−0.0251 (2)	−0.0121 (2)	−0.0044 (2)
O1	0.0496 (7)	0.0499 (7)	0.0406 (7)	−0.0133 (6)	−0.0141 (5)	−0.0075 (5)
O2	0.0579 (9)	0.0575 (9)	0.1130 (14)	−0.0244 (7)	−0.0186 (9)	−0.0208 (9)
O3	0.0557 (9)	0.0564 (9)	0.1072 (13)	−0.0179 (7)	−0.0286 (9)	0.0023 (9)
O4	0.0751 (10)	0.0872 (11)	0.0505 (8)	−0.0219 (9)	−0.0140 (7)	−0.0269 (8)
C1	0.0460 (9)	0.0439 (10)	0.0394 (9)	−0.0139 (8)	−0.0101 (7)	−0.0081 (7)
C2	0.0436 (9)	0.0383 (9)	0.0431 (9)	−0.0087 (7)	−0.0086 (7)	−0.0096 (7)
C3	0.0465 (10)	0.0432 (10)	0.0584 (12)	−0.0125 (8)	−0.0119 (9)	−0.0123 (9)
C4	0.0449 (10)	0.0376 (10)	0.0800 (14)	−0.0101 (8)	−0.0095 (10)	−0.0100 (9)
C5	0.0537 (12)	0.0419 (10)	0.0671 (13)	−0.0109 (9)	0.0000 (10)	0.0018 (9)
C6	0.0564 (12)	0.0489 (11)	0.0489 (11)	−0.0091 (9)	−0.0087 (9)	−0.0009 (9)
C7	0.0437 (9)	0.0416 (10)	0.0455 (10)	−0.0078 (8)	−0.0086 (7)	−0.0093 (8)
C8	0.0428 (9)	0.0448 (10)	0.0417 (9)	−0.0107 (8)	−0.0107 (7)	−0.0093 (7)
C9	0.0449 (10)	0.0534 (11)	0.0534 (11)	−0.0163 (8)	−0.0143 (8)	−0.0115 (9)
C10	0.0472 (10)	0.0557 (11)	0.0468 (10)	−0.0193 (9)	−0.0064 (8)	−0.0124 (8)
C11	0.095 (2)	0.0580 (16)	0.186 (4)	−0.0338 (16)	−0.030 (2)	−0.0244 (19)
C12	0.0659 (13)	0.0603 (13)	0.0673 (14)	−0.0152 (11)	−0.0275 (11)	−0.0009 (11)

Geometric parameters (Å, º)

Cl—C4	1.748 (2)	C4—C5	1.391 (3)
S—O4	1.4950 (17)	C5—C6	1.381 (3)
S—C1	1.7613 (18)	C5—H5	0.9300
S—C12	1.794 (2)	C6—C7	1.380 (3)
O1—C8	1.376 (2)	C6—H6	0.9300
O1—C7	1.377 (2)	C8—C9	1.482 (3)
O2—C10	1.327 (2)	C9—C10	1.504 (3)
O2—C11	1.454 (3)	C9—H9A	0.9700
O3—C10	1.194 (2)	C9—H9B	0.9700
C1—C8	1.350 (2)	C11—H11A	0.9600
C1—C2	1.443 (3)	C11—H11B	0.9600
C2—C7	1.394 (3)	C11—H11C	0.9600
C2—C3	1.396 (3)	C12—H12A	0.9600
C3—C4	1.378 (3)	C12—H12B	0.9600
C3—H3	0.94 (2)	C12—H12C	0.9600
O4—S—C1	105.98 (9)	C6—C7—C2	123.72 (18)
O4—S—C12	106.01 (11)	C1—C8—O1	110.86 (16)
C1—S—C12	98.50 (10)	C1—C8—C9	133.29 (17)
C8—O1—C7	106.35 (13)	O1—C8—C9	115.85 (15)
C10—O2—C11	116.4 (2)	C8—C9—C10	114.36 (15)
C8—C1—C2	107.57 (15)	C8—C9—H9A	108.7
C8—C1—S	124.18 (15)	C10—C9—H9A	108.7
C2—C1—S	127.95 (14)	C8—C9—H9B	108.7
C7—C2—C3	119.64 (17)	C10—C9—H9B	108.7
C7—C2—C1	104.63 (16)	H9A—C9—H9B	107.6
C3—C2—C1	135.72 (17)	O3—C10—O2	123.6 (2)
C4—C3—C2	116.31 (19)	O3—C10—C9	126.28 (19)
C4—C3—H3	121.9 (13)	O2—C10—C9	110.06 (16)
C2—C3—H3	121.8 (13)	O2—C11—H11A	109.5
C3—C4—C5	123.7 (2)	O2—C11—H11B	109.5
C3—C4—Cl	118.25 (17)	H11A—C11—H11B	109.5
C5—C4—Cl	118.09 (16)	O2—C11—H11C	109.5
C6—C5—C4	120.25 (19)	H11A—C11—H11C	109.5
C6—C5—H5	119.9	H11B—C11—H11C	109.5
C4—C5—H5	119.9	S—C12—H12A	109.5
C7—C6—C5	116.40 (19)	S—C12—H12B	109.5
C7—C6—H6	121.8	H12A—C12—H12B	109.5
C5—C6—H6	121.8	S—C12—H12C	109.5
O1—C7—C6	125.70 (17)	H12A—C12—H12C	109.5
O1—C7—C2	110.58 (15)	H12B—C12—H12C	109.5
O4—S—C1—C8	129.68 (17)	C5—C6—C7—C2	−1.4 (3)
C12—S—C1—C8	−120.88 (18)	C3—C2—C7—O1	−178.32 (15)
O4—S—C1—C2	−43.19 (19)	C1—C2—C7—O1	1.0 (2)
C12—S—C1—C2	66.26 (19)	C3—C2—C7—C6	1.4 (3)
C8—C1—C2—C7	−0.4 (2)	C1—C2—C7—C6	−179.31 (18)
S—C1—C2—C7	173.45 (14)	C2—C1—C8—O1	−0.4 (2)
C8—C1—C2—C3	178.8 (2)	S—C1—C8—O1	−174.49 (13)
S—C1—C2—C3	−7.4 (3)	C2—C1—C8—C9	−179.77 (19)
C7—C2—C3—C4	−0.2 (3)	S—C1—C8—C9	6.1 (3)
C1—C2—C3—C4	−179.2 (2)	C7—O1—C8—C1	1.0 (2)
C2—C3—C4—C5	−1.0 (3)	C7—O1—C8—C9	−179.52 (15)
C2—C3—C4—Cl	178.26 (14)	C1—C8—C9—C10	60.7 (3)
C3—C4—C5—C6	1.0 (3)	O1—C8—C9—C10	−118.61 (18)
Cl—C4—C5—C6	−178.22 (16)	C11—O2—C10—O3	0.5 (4)
C4—C5—C6—C7	0.2 (3)	C11—O2—C10—C9	179.1 (2)
C8—O1—C7—C6	179.08 (18)	C8—C9—C10—O3	−10.1 (3)
C8—O1—C7—C2	−1.22 (19)	C8—C9—C10—O2	171.31 (17)
C5—C6—C7—O1	178.32 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11C···Cg1^i	0.96	2.92	3.858 (2)	165
C3—H3···O4^ii	0.94 (2)	2.41 (2)	3.320 (3)	162.7 (17)
C9—H9B···O1^iii	0.97	2.59	3.550 (2)	172
C9—H9A···O4^iv	0.97	2.23	3.183 (3)	169

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