2-Methyl-5-phenyl-3-phenyl­sulfinyl-1-benzofuran

The title compound, C₂₁H₁₆O₂S, was prepared by the oxidation of 2-methyl-5-phenyl-3-phenyl­sulfanyl-1-benzofuran using 3-chloro­perbenzoic acid. The O atom and the phenyl group of the phenyl­sulfinyl substituent lie on opposite sides of the plane of the benzofuran unit. The 3-phenyl group is almost perpendicular to the plane of the benzofuran fragment [80.4 (6)°] and is tilted slightly towards it. The 5-phenyl ring is rotated out of the benzofuran plane with a dihedral angle of 21.0 (1)°. The crystal structure is stabilized by CH₂—H(methyl)...π(benzofuran) interactions.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.047
• wR factor = 0.111
• Data-to-parameter ratio = 14.5

checkCIF/PLATON results

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Alert level C
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.65 mm

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

As part of our continuing studies on the synthesis and structure of 5-phenyl-1-benzofuran analogues, the crystal structures of 3-methylsulfanyl-2,5-diphenyl-1-benzofuran (Choi, Seo, Kang et al., 2006) and 2-methyl-3-methylsulfinyl-5-phenyl-1-benzofuran (Choi, Seo, Lee et al., 2006) have been described to the literature. Herein we report the molecular and crystal structure of the title compound (I) (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.008 Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle in (I) formed by the plane of the benzofuran ring and the plane of 5-phenyl ring is 21.0 (1)° and phenyl ring(C15—C20) with 80.4 (6)° lies toward benzofuran plane. The molecular packing (Fig. 2) is stabilized by CH₂—H···π interactions between the methyl group and the benzene ring of benzofuran unit, with a C21—H21B···Cg1ⁱ separation of 2.94 Å. (Cg1 is the centroid of the C3—C8 benzene ring, symmetry code as in Fig. 2).

Related literature

For the crystal structures of the isomers of the title compound, see: Choi, Seo, Kang et al. (2006); Choi, Seo, Lee et al. (2006).

S2. Experimental

3-Chloroperbenzoic acid (77%, 291 mg, 1.30 mmol) was added in small portions to a stirred solution of 2-methyl-5-phenyl-3-phenylsulfanyl-1-benzofuran (379 mg, 1.20 mmol) in dichloromethane (30 ml) at 273 K. After being stirred at room temperature for 1hr, the mixture was washed with saturated sodium bicarbonate solution and the organic layer separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (hexane-ethyl acetate, 1:1 v/v) to afford the title compound as a colorless solid [yield 78%, m.p. 425–426 K; R_f = 0.51 (hexane-ethyl acetate, 1:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a dilute solution of title compound (I) in acetone at room temperature.

S3. Refinement

All H atoms were geometrically located in ideal positions and refined using a riding model, with C—H = 0.93 Å for aromatic H atoms and C—H = 0.96 Å for methyl H atoms, and with U_iso(H) = 1.2Ueq(C) for aromatic H atoms, and U_iso(H) = 1.5Ueq(C) for methyl H atoms. The highest peak in the difference map is 1.21 Å from S and the largest hole is 0.34 Å from S.

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. CH2—H···π interactions (dashed lines) in (I). Cg denotes ring centroid. [Symmetry codes: (i) 1/2 - x, 1/2 + y, 1/2 - z; (ii) 1/2 - x, y - 1/2, 1/2 - z.]

2-Methyl-5-phenyl-3-phenylsulfinyl-1-benzofuran

Crystal data

C21H16O2S	F(000) = 696
Mr = 332.40	Dx = 1.371 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -p_2yn	Cell parameters from 6665 reflections
a = 9.8919 (5) Å	θ = 2.4–28.3°
b = 9.6229 (5) Å	µ = 0.21 mm^−1
c = 16.9226 (9) Å	T = 173 K
β = 91.685 (1)°	Block, colorless
V = 1610.15 (14) Å^3	0.65 × 0.42 × 0.35 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	2942 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.030
Graphite monochromator	θmax = 26.0°, θmin = 2.4°
Detector resolution: 10.00 pixels mm^-1	h = −12→12
φ and ω scans	k = −11→10
8853 measured reflections	l = −17→20
3154 independent 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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.111	H-atom parameters constrained
S = 1.16	w = 1/[σ^2(Fo^2) + (0.042P)^2 + 1.3632P] where P = (Fo^2 + 2Fc^2)/3
3154 reflections	(Δ/σ)max < 0.001
218 parameters	Δρmax = 0.62 e Å^−3
0 restraints	Δρmin = −0.41 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	0.08659 (5)	0.14104 (5)	0.34971 (3)	0.02305 (15)
O1	0.45015 (14)	0.03554 (15)	0.28292 (8)	0.0268 (3)
O2	0.00179 (15)	0.02393 (16)	0.37785 (9)	0.0315 (4)
C1	0.25122 (19)	0.0754 (2)	0.33966 (11)	0.0216 (4)
C2	0.3295 (2)	0.1062 (2)	0.27759 (11)	0.0245 (4)
C3	0.4471 (2)	−0.0421 (2)	0.35150 (11)	0.0228 (4)
C4	0.5483 (2)	−0.1282 (2)	0.38024 (12)	0.0273 (4)
H4	0.6298	−0.1412	0.3528	0.033*
C5	0.5256 (2)	−0.1948 (2)	0.45110 (12)	0.0253 (4)
H5	0.5940	−0.2539	0.4729	0.030*
C6	0.40448 (19)	−0.1783 (2)	0.49227 (11)	0.0213 (4)
C7	0.30329 (19)	−0.0919 (2)	0.46039 (11)	0.0207 (4)
H7	0.2201	−0.0811	0.4864	0.025*
C8	0.32614 (19)	−0.02158 (19)	0.38991 (11)	0.0207 (4)
C9	0.38708 (19)	−0.2488 (2)	0.56998 (11)	0.0219 (4)
C10	0.4633 (2)	−0.3664 (2)	0.59166 (12)	0.0291 (5)
H10	0.5261	−0.4035	0.5558	0.035*
C11	0.4484 (2)	−0.4295 (2)	0.66456 (13)	0.0336 (5)
H11	0.5020	−0.5083	0.6783	0.040*
C12	0.3565 (2)	−0.3791 (2)	0.71746 (13)	0.0340 (5)
H12	0.3464	−0.4227	0.7673	0.041*
C13	0.2792 (2)	−0.2639 (2)	0.69661 (12)	0.0319 (5)
H13	0.2154	−0.2286	0.7323	0.038*
C14	0.2945 (2)	−0.1996 (2)	0.62387 (12)	0.0260 (4)
H14	0.2408	−0.1207	0.6106	0.031*
C15	0.11738 (19)	0.2550 (2)	0.43243 (11)	0.0223 (4)
C16	0.0866 (2)	0.2136 (2)	0.50802 (12)	0.0274 (4)
H16	0.0506	0.1238	0.5175	0.033*
C17	0.1093 (2)	0.3064 (3)	0.56983 (12)	0.0331 (5)
H17	0.0904	0.2792	0.6223	0.040*
C18	0.1594 (2)	0.4382 (2)	0.55570 (13)	0.0337 (5)
H18	0.1739	0.5012	0.5983	0.040*
C19	0.1883 (2)	0.4783 (2)	0.47930 (14)	0.0338 (5)
H19	0.2225	0.5687	0.4696	0.041*
C20	0.1674 (2)	0.3867 (2)	0.41729 (13)	0.0281 (4)
H20	0.1871	0.4137	0.3649	0.034*
C21	0.3119 (2)	0.2026 (2)	0.20968 (12)	0.0317 (5)
H21A	0.2160	0.2266	0.2026	0.047*
H21B	0.3435	0.1577	0.1616	0.047*
H21C	0.3646	0.2873	0.2199	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S	0.0224 (3)	0.0228 (3)	0.0238 (3)	0.00043 (18)	−0.00299 (18)	0.00061 (19)
O1	0.0292 (8)	0.0299 (8)	0.0215 (7)	0.0001 (6)	0.0057 (6)	0.0012 (6)
O2	0.0272 (8)	0.0300 (8)	0.0374 (8)	−0.0067 (6)	−0.0001 (6)	−0.0012 (6)
C1	0.0244 (10)	0.0202 (9)	0.0200 (9)	−0.0009 (8)	−0.0010 (7)	−0.0011 (7)
C2	0.0288 (10)	0.0218 (10)	0.0228 (10)	−0.0014 (8)	−0.0005 (8)	−0.0024 (8)
C3	0.0258 (10)	0.0231 (10)	0.0195 (9)	−0.0022 (8)	0.0024 (7)	−0.0018 (7)
C4	0.0234 (10)	0.0305 (11)	0.0284 (10)	0.0027 (8)	0.0069 (8)	−0.0038 (9)
C5	0.0218 (10)	0.0268 (10)	0.0274 (10)	0.0043 (8)	−0.0002 (8)	−0.0029 (8)
C6	0.0230 (9)	0.0205 (9)	0.0204 (9)	−0.0012 (7)	−0.0007 (7)	−0.0024 (7)
C7	0.0209 (9)	0.0219 (9)	0.0194 (9)	−0.0007 (7)	0.0019 (7)	−0.0021 (7)
C8	0.0219 (9)	0.0190 (9)	0.0211 (9)	−0.0007 (7)	−0.0020 (7)	−0.0046 (7)
C9	0.0199 (9)	0.0223 (9)	0.0234 (9)	−0.0023 (7)	−0.0038 (7)	−0.0011 (8)
C10	0.0273 (11)	0.0301 (11)	0.0296 (11)	0.0040 (9)	−0.0010 (8)	0.0014 (9)
C11	0.0335 (12)	0.0316 (12)	0.0353 (12)	0.0056 (9)	−0.0077 (9)	0.0068 (9)
C12	0.0382 (12)	0.0380 (12)	0.0254 (10)	−0.0054 (10)	−0.0034 (9)	0.0097 (9)
C13	0.0335 (11)	0.0373 (12)	0.0250 (10)	−0.0006 (9)	0.0036 (8)	0.0020 (9)
C14	0.0267 (10)	0.0252 (10)	0.0261 (10)	0.0016 (8)	0.0003 (8)	0.0017 (8)
C15	0.0169 (9)	0.0232 (10)	0.0267 (10)	0.0037 (7)	−0.0013 (7)	−0.0019 (8)
C16	0.0226 (10)	0.0311 (11)	0.0287 (10)	0.0008 (8)	0.0034 (8)	0.0020 (9)
C17	0.0245 (11)	0.0491 (14)	0.0257 (10)	0.0069 (10)	0.0022 (8)	−0.0011 (10)
C18	0.0256 (11)	0.0399 (13)	0.0354 (12)	0.0061 (9)	−0.0050 (9)	−0.0141 (10)
C19	0.0345 (12)	0.0260 (11)	0.0405 (12)	−0.0026 (9)	−0.0041 (9)	−0.0032 (9)
C20	0.0295 (11)	0.0254 (10)	0.0296 (11)	−0.0005 (8)	−0.0002 (8)	0.0024 (8)
C21	0.0397 (12)	0.0300 (11)	0.0254 (10)	−0.0016 (9)	0.0028 (9)	0.0045 (9)

Geometric parameters (Å, º)

S—O2	1.491 (2)	C11—C12	1.383 (3)
S—C1	1.760 (2)	C11—H11	0.9500
S—C15	1.797 (2)	C12—C13	1.386 (3)
O1—C2	1.374 (2)	C12—H12	0.9500
O1—C3	1.381 (2)	C13—C14	1.390 (3)
C1—C2	1.356 (3)	C13—H13	0.9500
C1—C8	1.451 (3)	C14—H14	0.9500
C2—C21	1.483 (3)	C15—C16	1.382 (3)
C3—C4	1.377 (3)	C15—C20	1.387 (3)
C3—C8	1.392 (3)	C16—C17	1.388 (3)
C4—C5	1.384 (3)	C16—H16	0.9500
C4—H4	0.9500	C17—C18	1.385 (3)
C5—C6	1.412 (3)	C17—H17	0.9500
C5—H5	0.9500	C18—C19	1.387 (3)
C6—C7	1.397 (3)	C18—H18	0.9500
C6—C9	1.494 (3)	C19—C20	1.381 (3)
C7—C8	1.395 (3)	C19—H19	0.9500
C7—H7	0.9500	C20—H20	0.9500
C9—C14	1.394 (3)	C21—H21A	0.9800
C9—C10	1.403 (3)	C21—H21B	0.9800
C10—C11	1.387 (3)	C21—H21C	0.9800
C10—H10	0.9500
O2—S—C1	106.89 (9)	C12—C11—H11	119.6
O2—S—C15	107.25 (9)	C10—C11—H11	119.6
C1—S—C15	99.10 (9)	C11—C12—C13	118.9 (2)
C2—O1—C3	106.39 (15)	C11—C12—H12	120.5
C2—C1—C8	107.53 (17)	C13—C12—H12	120.5
C2—C1—S	123.21 (15)	C12—C13—C14	120.5 (2)
C8—C1—S	129.21 (15)	C12—C13—H13	119.7
C1—C2—O1	110.83 (17)	C14—C13—H13	119.7
C1—C2—C21	132.87 (19)	C13—C14—C9	121.25 (19)
O1—C2—C21	116.25 (17)	C13—C14—H14	119.4
C4—C3—O1	126.03 (17)	C9—C14—H14	119.4
C4—C3—C8	123.11 (18)	C16—C15—C20	121.57 (19)
O1—C3—C8	110.86 (17)	C16—C15—S	120.54 (16)
C3—C4—C5	116.71 (18)	C20—C15—S	117.84 (15)
C3—C4—H4	121.6	C15—C16—C17	118.5 (2)
C5—C4—H4	121.6	C15—C16—H16	120.8
C4—C5—C6	122.48 (18)	C17—C16—H16	120.8
C4—C5—H5	118.8	C18—C17—C16	120.6 (2)
C6—C5—H5	118.8	C18—C17—H17	119.7
C7—C6—C5	119.01 (17)	C16—C17—H17	119.7
C7—C6—C9	120.69 (17)	C17—C18—C19	120.0 (2)
C5—C6—C9	120.27 (17)	C17—C18—H18	120.0
C8—C7—C6	119.09 (17)	C19—C18—H18	120.0
C8—C7—H7	120.5	C20—C19—C18	120.0 (2)
C6—C7—H7	120.5	C20—C19—H19	120.0
C3—C8—C7	119.57 (18)	C18—C19—H19	120.0
C3—C8—C1	104.39 (17)	C19—C20—C15	119.3 (2)
C7—C8—C1	136.04 (18)	C19—C20—H20	120.4
C14—C9—C10	117.47 (18)	C15—C20—H20	120.4
C14—C9—C6	121.08 (17)	C2—C21—H21A	109.5
C10—C9—C6	121.45 (18)	C2—C21—H21B	109.5
C11—C10—C9	121.0 (2)	H21A—C21—H21B	109.5
C11—C10—H10	119.5	C2—C21—H21C	109.5
C9—C10—H10	119.5	H21A—C21—H21C	109.5
C12—C11—C10	120.8 (2)	H21B—C21—H21C	109.5
O2—S—C1—C2	137.76 (17)	C2—C1—C8—C7	−179.6 (2)
C15—S—C1—C2	−110.99 (18)	S—C1—C8—C7	−2.3 (3)
O2—S—C1—C8	−39.2 (2)	C7—C6—C9—C14	−20.5 (3)
C15—S—C1—C8	72.04 (19)	C5—C6—C9—C14	157.58 (19)
C8—C1—C2—O1	0.5 (2)	C7—C6—C9—C10	159.74 (19)
S—C1—C2—O1	−177.00 (13)	C5—C6—C9—C10	−22.2 (3)
C8—C1—C2—C21	−176.5 (2)	C14—C9—C10—C11	−1.1 (3)
S—C1—C2—C21	5.9 (3)	C6—C9—C10—C11	178.67 (19)
C3—O1—C2—C1	−0.3 (2)	C9—C10—C11—C12	0.9 (3)
C3—O1—C2—C21	177.31 (17)	C10—C11—C12—C13	−0.2 (3)
C2—O1—C3—C4	−179.52 (19)	C11—C12—C13—C14	−0.4 (3)
C2—O1—C3—C8	−0.1 (2)	C12—C13—C14—C9	0.1 (3)
O1—C3—C4—C5	178.85 (18)	C10—C9—C14—C13	0.6 (3)
C8—C3—C4—C5	−0.5 (3)	C6—C9—C14—C13	−179.17 (18)
C3—C4—C5—C6	0.9 (3)	O2—S—C15—C16	11.79 (18)
C4—C5—C6—C7	0.2 (3)	C1—S—C15—C16	−99.18 (17)
C4—C5—C6—C9	−177.89 (18)	O2—S—C15—C20	−165.60 (15)
C5—C6—C7—C8	−1.7 (3)	C1—S—C15—C20	83.43 (16)
C9—C6—C7—C8	176.44 (17)	C20—C15—C16—C17	−1.3 (3)
C4—C3—C8—C7	−0.9 (3)	S—C15—C16—C17	−178.60 (15)
O1—C3—C8—C7	179.63 (16)	C15—C16—C17—C18	1.2 (3)
C4—C3—C8—C1	179.85 (19)	C16—C17—C18—C19	−0.5 (3)
O1—C3—C8—C1	0.4 (2)	C17—C18—C19—C20	−0.1 (3)
C6—C7—C8—C3	2.0 (3)	C18—C19—C20—C15	0.0 (3)
C6—C7—C8—C1	−179.1 (2)	C16—C15—C20—C19	0.7 (3)
C2—C1—C8—C3	−0.6 (2)	S—C15—C20—C19	178.06 (16)
S—C1—C8—C3	176.78 (15)