organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

2,6-Bis(4-meth­­oxy­phen­yl)-1,4-dithiine

aDepartment of Chemistry, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China
*Correspondence e-mail: pzh7251@yahoo.com, deliean@hnu.edu.cn

(Received 13 December 2013; accepted 8 January 2014; online 15 January 2014)

The title mol­ecule, C18H16O2S2, reveals crystallographic twofold rotation symmetry (with both S atoms lying on the axis) and one half-mol­ecule defines an asymmetric unit. The dithiine ring is in a boat conformation. The aromatic ring and the C=C bond are nearly coplanar, with small torsion angles of −171.26 (19) and 8.5 (3)°. The two S—C bond lengths [1.7391 (19) and 1.7795 (18) Å] are shorter than single C—S bonds and longer than analogous C=S double bonds, which indicates a certain degree of conjugation between the lone pair on the S atom and π electrons of the C=C bond. The crystal packing only features van der Waals inter­actions.

Related literature

For a similar crystal structure, 2,6-diphenyl-1,4-dithiine, see: Piao et al. (2004[Piao, X. H., Sugihara, Y. & Nakayama, J. (2004). Heteroat. Chem. 15, 424-427.]). For background to 1,4-dithiine derivatives, see: Kobayashi & Gajurel (1986[Kobayashi, K. & Gajurel, C. L. (1986). Sulfur Rep. 7, 123-148.]); Scott et al. (2000[Scott, M. K., Ross, T. M., Lee, D. H. S., Wang, H., Shank, R. P., Wild, K. D., Davis, C. B., Crooke, J. J., Potocki, A. C. & Reitz, A. B. (2000). Bioorg. Med. Chem. 8, 1383-1391.]). For the synthesis of a similar compound, see: Nakayama et al. (1984[Nakayama, J., Motoyama, H., Machida, H., Shimomura, M. & Hoshino, M. (1984). Heterocycles, 22, 1527-1530.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C18H16O2S2

  • Mr = 328.43

  • Orthorhombic, P n m a

  • a = 10.1330 (11) Å

  • b = 27.318 (3) Å

  • c = 5.5402 (6) Å

  • V = 1533.6 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.35 mm−1

  • T = 293 K

  • 0.21 × 0.18 × 0.09 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.121, Tmax = 1.000

  • 8513 measured reflections

  • 1541 independent reflections

  • 1258 reflections with I > 2σ(I)

  • Rint = 0.043

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.102

  • S = 1.04

  • 1541 reflections

  • 104 parameters

  • H-atom parameters constrained

  • Δρmax = 0.29 e Å−3

  • Δρmin = −0.16 e Å−3

Data collection: SMART (Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

1,4-Dithiine derivatives are very important intermediates in organic synthesis and can be used as versatile building blocks for a variety of chemical purposes (Kobayashi & Gajurel, 1986). In addition, some 1,4-dithiine derivatives have exhibited good biological activities, For example, Scott et al. showed that 2,3-dihydro-2-phenyl-1,4-dithiin-1,1,4,4-tetroxide could be used as nonpeptide antagonist of the human Galanin hGAL-1 receptor (Scott et al., 2000). Unfortunately, there are very few acceptable methods to prepare 1,4-dithiine compounds thus far, and, in most cases, a successful protocol must use bis(arylethanonyl) sulfides compounds as precursors. Herein we report a new synthetic approaches and crystal structure of 2,6-bis(4-methoxyphenyl)-1,4-dithiine.

The molecular structure of the title compound(I) (Fig. 1) exhibits a twofold rotation axes symmetry. The dithiine ring is in a boat conformation. In the crystal, dominate columns of assembled molecules, however, their separation distances are larger than 5.5402 (13) Å (Fig. 2). The bond lengths of C1—C2 in heterocyclic ring presents a characteristic of the C=C double bond. An aromatic ring and the C=C bond are nearly coplanar, with small torsion angles of -171.26 (19)° and 8.5 (3)° for C1—C2—C3—C4 and C1—C2—C3—C8,respectively ·. The two characteristic bond lengths of S1—C2 and S2—C1 are shorter than C—S single bonds and longer than analogous C=S double bonds (Allen et al., 1987), which indicates a certain degree of conjugation between the lone pair on the sulfur atom and π electrons of the C=C bond.

Related literature top

For a similar crystal structure, 2,6-diphenyl-1,4-dithiine, see: Piao et al. (2004). For background to 1,4-dithiine derivatives, see: Kobayashi & Gajurel (1986); Scott et al. (2000). For the synthesis of a similar compound, see: Nakayama et al. (1984). For standard bond lengths, see: Allen et al. (1987).

Experimental top

NaOEt (224 mg, 3.3 mmol) was dissolved in alcohol (10 mL), and then added to bis(4-methoxyphenylethynyl) sulfide (97.8 mg,0.33 mmol). After the mixture was stirred at room temperature for 10 min, Na2S·9H2O (159 mg, 0.66 mmol) was added. The resulting mixture was then stirred at reflux temperature for 2 h. The reaction mixture was cooled to room temperature and quenched by water and extracted with dichloromethane. The extract was then washed with brine, dried over Na2SO4, and filtered. The solvent was evaporated in vacuo, and the residue was chromatographed (SiO2; eluent, ether/dichloromethane, 4: 1) to give 93 mg of compound I (85%) as a yellow solid: mp 401–403 K; 1H NMR (400 MHz, CDCl3): δ = 3.83 (s, 6H; OCH3), 6.42 (s, 2H; CH), 6.89(d, J = 8.8 Hz, 4H; Ar—H), 7.58 (d, J = 8.8 Hz, 4H; Ar—H); 13C NMR (100 MHz, CDCl3): δ = 55.50 (OCH3), 114.07 (CH), 116.40 (CH), 128.45 (CH), 129.83 (C), 139.52 (C), 160.10 (C); IR (KBr): ν = 3020, 2959, 2914, 1607, 1508, 1457, 1258, 1191, 832 cm-1; MS (EI): m/z (%): 328.2 (M+, 100), 313.1 (43); HRMS (EI): m/z Calcd for C18H16O2S2 328.0584, Found 328.0586.

Single crystals of (I) suitable for X-ray diffraction analysis was obtained by slow diffusion of petroleum ether into a dichloromethane solution at 298 K.

Refinement top

H atoms were refined with fixed individual displacement parameters [Uiso (H) = 1.2 Ueq (C) and Uiso (H) = 1.5 Ueq (C methyl)] using a riding model, with aromatic C—H = 0.93 Å, methyl C—H = 0.96 Å.

Structure description top

1,4-Dithiine derivatives are very important intermediates in organic synthesis and can be used as versatile building blocks for a variety of chemical purposes (Kobayashi & Gajurel, 1986). In addition, some 1,4-dithiine derivatives have exhibited good biological activities, For example, Scott et al. showed that 2,3-dihydro-2-phenyl-1,4-dithiin-1,1,4,4-tetroxide could be used as nonpeptide antagonist of the human Galanin hGAL-1 receptor (Scott et al., 2000). Unfortunately, there are very few acceptable methods to prepare 1,4-dithiine compounds thus far, and, in most cases, a successful protocol must use bis(arylethanonyl) sulfides compounds as precursors. Herein we report a new synthetic approaches and crystal structure of 2,6-bis(4-methoxyphenyl)-1,4-dithiine.

The molecular structure of the title compound(I) (Fig. 1) exhibits a twofold rotation axes symmetry. The dithiine ring is in a boat conformation. In the crystal, dominate columns of assembled molecules, however, their separation distances are larger than 5.5402 (13) Å (Fig. 2). The bond lengths of C1—C2 in heterocyclic ring presents a characteristic of the C=C double bond. An aromatic ring and the C=C bond are nearly coplanar, with small torsion angles of -171.26 (19)° and 8.5 (3)° for C1—C2—C3—C4 and C1—C2—C3—C8,respectively ·. The two characteristic bond lengths of S1—C2 and S2—C1 are shorter than C—S single bonds and longer than analogous C=S double bonds (Allen et al., 1987), which indicates a certain degree of conjugation between the lone pair on the sulfur atom and π electrons of the C=C bond.

For a similar crystal structure, 2,6-diphenyl-1,4-dithiine, see: Piao et al. (2004). For background to 1,4-dithiine derivatives, see: Kobayashi & Gajurel (1986); Scott et al. (2000). For the synthesis of a similar compound, see: Nakayama et al. (1984). For standard bond lengths, see: Allen et al. (1987).

Computing details top

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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Structural unit of the title molecule with atom labelling scheme and 50% probability displacement ellipsoids. Symmetry code to generate the entire molecule:x,-y+1/2,z.
[Figure 2] Fig. 2. Crystal packing reveals a columns of molecules held together by van der Waals interactions, only.
2,6-Bis(4-methoxyphenyl)-1,4-dithiine top
Crystal data top
C18H16O2S2F(000) = 688
Mr = 328.43Dx = 1.422 Mg m3
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 1658 reflections
a = 10.1330 (11) Åθ = 7.5–53.8°
b = 27.318 (3) ŵ = 0.35 mm1
c = 5.5402 (6) ÅT = 293 K
V = 1533.6 (3) Å3Prismatic, yellow
Z = 40.21 × 0.18 × 0.09 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1541 independent reflections
Radiation source: fine-focus sealed tube1258 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.043
phi and ω scansθmax = 26.0°, θmin = 3.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 1212
Tmin = 0.121, Tmax = 1.000k = 3332
8513 measured reflectionsl = 56
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.102H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0554P)2 + 0.3159P]
where P = (Fo2 + 2Fc2)/3
1541 reflections(Δ/σ)max < 0.001
104 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.16 e Å3
Crystal data top
C18H16O2S2V = 1533.6 (3) Å3
Mr = 328.43Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 10.1330 (11) ŵ = 0.35 mm1
b = 27.318 (3) ÅT = 293 K
c = 5.5402 (6) Å0.21 × 0.18 × 0.09 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
1541 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
1258 reflections with I > 2σ(I)
Tmin = 0.121, Tmax = 1.000Rint = 0.043
8513 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.102H-atom parameters constrained
S = 1.04Δρmax = 0.29 e Å3
1541 reflectionsΔρmin = 0.16 e Å3
104 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
S10.49280 (7)0.25000.16602 (12)0.0352 (2)
S20.70856 (7)0.25000.24173 (15)0.0423 (2)
O10.14361 (14)0.45648 (5)0.0468 (3)0.0484 (4)
C10.60102 (19)0.29896 (6)0.2021 (4)0.0364 (5)
H10.61150.32620.30110.044*
C20.50486 (19)0.29989 (6)0.0393 (3)0.0307 (4)
C30.40701 (18)0.33990 (6)0.0143 (3)0.0296 (4)
C40.3199 (2)0.34206 (7)0.1786 (4)0.0364 (5)
H40.32130.31720.29310.044*
C50.2311 (2)0.38017 (7)0.2059 (3)0.0372 (5)
H50.17460.38080.33810.045*
C60.22660 (19)0.41714 (7)0.0376 (3)0.0352 (5)
C70.31115 (19)0.41530 (7)0.1595 (4)0.0395 (5)
H70.30830.43990.27530.047*
C80.3984 (2)0.37754 (7)0.1841 (4)0.0371 (5)
H80.45370.37690.31800.044*
C90.0549 (2)0.45883 (8)0.2462 (5)0.0556 (6)
H9A0.00050.43010.24790.083*
H9B0.00020.48740.23110.083*
H9C0.10430.46060.39380.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0430 (4)0.0328 (4)0.0297 (4)0.0000.0017 (3)0.000
S20.0266 (4)0.0405 (4)0.0599 (5)0.0000.0101 (3)0.000
O10.0487 (9)0.0401 (8)0.0563 (10)0.0129 (7)0.0112 (7)0.0073 (7)
C10.0326 (10)0.0306 (9)0.0459 (12)0.0035 (8)0.0042 (9)0.0016 (8)
C20.0304 (9)0.0287 (9)0.0332 (11)0.0063 (8)0.0021 (8)0.0015 (7)
C30.0290 (10)0.0274 (9)0.0324 (10)0.0058 (8)0.0013 (8)0.0028 (7)
C40.0416 (11)0.0314 (9)0.0361 (11)0.0007 (8)0.0067 (8)0.0043 (8)
C50.0397 (11)0.0362 (10)0.0357 (11)0.0002 (9)0.0093 (9)0.0000 (8)
C60.0333 (10)0.0305 (10)0.0420 (11)0.0001 (8)0.0015 (9)0.0015 (8)
C70.0421 (11)0.0382 (10)0.0381 (11)0.0000 (9)0.0019 (9)0.0095 (9)
C80.0383 (11)0.0397 (10)0.0331 (11)0.0004 (9)0.0062 (8)0.0030 (8)
C90.0548 (14)0.0493 (13)0.0627 (15)0.0180 (11)0.0168 (12)0.0019 (12)
Geometric parameters (Å, º) top
S1—C21.7795 (18)C4—C51.384 (3)
S1—C2i1.7795 (18)C4—H40.9300
S2—C11.7391 (19)C5—C61.375 (3)
S2—C1i1.7391 (19)C5—H50.9300
O1—C61.365 (2)C6—C71.389 (3)
O1—C91.426 (3)C7—C81.365 (3)
C1—C21.328 (3)C7—H70.9300
C1—H10.9300C8—H80.9300
C2—C31.482 (3)C9—H9A0.9600
C3—C41.387 (3)C9—H9B0.9600
C3—C81.397 (3)C9—H9C0.9600
C2—S1—C2i99.97 (12)C4—C5—H5120.0
C1—S2—C1i100.54 (13)O1—C6—C5124.98 (18)
C6—O1—C9116.92 (16)O1—C6—C7115.96 (17)
C2—C1—S2124.07 (15)C5—C6—C7119.06 (18)
C2—C1—H1118.0C8—C7—C6120.36 (18)
S2—C1—H1118.0C8—C7—H7119.8
C1—C2—C3124.65 (16)C6—C7—H7119.8
C1—C2—S1118.03 (15)C7—C8—C3121.97 (18)
C3—C2—S1117.32 (14)C7—C8—H8119.0
C4—C3—C8116.60 (17)C3—C8—H8119.0
C4—C3—C2121.94 (16)O1—C9—H9A109.5
C8—C3—C2121.46 (16)O1—C9—H9B109.5
C5—C4—C3121.98 (17)H9A—C9—H9B109.5
C5—C4—H4119.0O1—C9—H9C109.5
C3—C4—H4119.0H9A—C9—H9C109.5
C6—C5—C4120.00 (18)H9B—C9—H9C109.5
C6—C5—H5120.0
C1i—S2—C1—C239.0 (2)C3—C4—C5—C60.6 (3)
S2—C1—C2—C3175.75 (14)C9—O1—C6—C50.4 (3)
S2—C1—C2—S14.9 (2)C9—O1—C6—C7179.31 (19)
C2i—S1—C2—C148.1 (2)C4—C5—C6—O1179.75 (18)
C2i—S1—C2—C3132.49 (11)C4—C5—C6—C70.6 (3)
C1—C2—C3—C4171.26 (19)O1—C6—C7—C8179.64 (18)
S1—C2—C3—C48.1 (2)C5—C6—C7—C80.7 (3)
C1—C2—C3—C88.5 (3)C6—C7—C8—C30.5 (3)
S1—C2—C3—C8172.18 (14)C4—C3—C8—C71.6 (3)
C8—C3—C4—C51.7 (3)C2—C3—C8—C7178.16 (18)
C2—C3—C4—C5178.07 (17)
Symmetry code: (i) x, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC18H16O2S2
Mr328.43
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)293
a, b, c (Å)10.1330 (11), 27.318 (3), 5.5402 (6)
V3)1533.6 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.35
Crystal size (mm)0.21 × 0.18 × 0.09
Data collection
DiffractometerBruker SMART CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.121, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
8513, 1541, 1258
Rint0.043
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.102, 1.04
No. of reflections1541
No. of parameters104
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.29, 0.16

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

The work was supported financially by the National Natural Science Foundation of China (No. 21072052) and the Hunan Provincial Science and Technology Department Program (No. 2011 W K4007).

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CSD CrossRef Web of Science Google Scholar
First citationBruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationKobayashi, K. & Gajurel, C. L. (1986). Sulfur Rep. 7, 123–148.  CrossRef CAS Google Scholar
First citationNakayama, J., Motoyama, H., Machida, H., Shimomura, M. & Hoshino, M. (1984). Heterocycles, 22, 1527–1530.  CrossRef CAS Google Scholar
First citationPiao, X. H., Sugihara, Y. & Nakayama, J. (2004). Heteroat. Chem. 15, 424–427.  Web of Science CSD CrossRef CAS Google Scholar
First citationScott, M. K., Ross, T. M., Lee, D. H. S., Wang, H., Shank, R. P., Wild, K. D., Davis, C. B., Crooke, J. J., Potocki, A. C. & Reitz, A. B. (2000). Bioorg. Med. Chem. 8, 1383–1391.  Web of Science CrossRef PubMed CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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