1,8-Dioxa-4,11-di­thia­cyclo­tetra­decane-2,9-dione

The title compound, C₁₀H₁₆O₄S₂, was formed in a reaction of allyl alcohol and thio­glycolic acid followed by acid-catalyzed esterification of the resulting hydroxy acid. The compound forms triclinic crystals and there is an inversion center in the middle of the mol­ecule The structure was determined to be a 14-membered dilide which in the solid state assumes a centrosymmetric conformation where the S-C-C-O-C-C-C-S chain is roughly gauche-gauche-anti-anti-gauche-anti-gauche. Molecular-mechanics calculations showed that the X-ray conformation is 10 kJ above the global minimum.

Key indicators

• Single-crystal X-ray study
• T = 193 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.048
• wR factor = 0.129
• Data-to-parameter ratio = 10.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



ABSTM_02  When printed, the submitted absorption T values will be replaced
          by the scaled T values. Since the ratio of scaled T's is
          identical to the ratio of reported T values, the scaling does
          not imply a change to the absorption corrections used in the
          study.
          Ratio of Tmax expected/reported      0.916
          Tmax scaled      0.916 Tmin scaled      0.811

---

S1. Comment

In an attempt to prepare 1,4-oxathian-2-one (Koskimies, 1984), allyl alcohol and thioglycolic acid were reacted followed by acid-catalyzed esterification of the hydroxy acid formed. A crystalline product, believed to be 1,4-thiepan-2-one (Davies et al., 1977) on the basis of its NMR spectrum, was obtained. However, its mass spectrum showed a molecular ion peak of 264, suggesting the dimer. The structure of the dimer was confirmed by X-ray structure analysis as a 14-membered dilide. The formation of the 14-membered ring rather than seven-membered lactone is probably facilitated by the presence of sulfur with long C—S bonds in the hydroxy acid chain: the seven-membered lactone is more strained than the corresponding carbocyclic lactone or the 14-membered dilide. In the solid state, the compound assumes a centrosymmetric conformation where the S1—C2—C3—O4—C5—C6—C7—S1A chain is roughly gauche-gauche-anti-anti-gauche-anti-gauche. The conformation may be classified as [77] using Dale's nomenclature (Dale, 1973) with corner points at both S atoms. This unusual structure is made possible by two parallel planar ester groups: C2, C3, O8, O4 and C5 are practically in the plane. The corresponding carbon dilide 1,8-dioxacyclotetradecane-2,9-dione (Groth, 1985), as well as tridecanolactone (Wiberg et al., 1991), both crystallize in the [3434] conformation. The latter diamond-lattice conformation is also preferred by the parent hydrocarbon cyclotetradecane (Ounsworth & Weiler, 1987). Molecular-mechanics calculations (Mohamadi, 1990) showed that the X-ray conformation is 10 kJ above the global minimum. This minimum-energy conformer is also centrosymmetric and of the [3434] type, the corner points in 2, 6, 2' and 6'. The conformation is very similar to that of 1,8-dioxacyclotetradecane-2,9-dione (Groth, 1985). The main difference between X-ray structure and the minimum conformation is that the latter is square-shaped with carbonyl bonds axial with respect to the molecular plain while the X-ray conformation is oval-shaped with S atoms at the both ends and the carbonyl O atoms in the ring plane. Molecular-mechanics calculations suggest that the solid-state conformation is favored in more polar media. Analysis of vicinal coupling constants in the ¹H NMR spectrum indicate that in solution no single conformation is dominating, a fact also predicted by molecular-mechanics calculations.

S2. Experimental

The title compound was prepared by mixing aqueous (80%) thioglycolic acid (10 ml, 0.15 mol) and allyl alcohol (13.5 ml, 0.15 mol). When the reaction has subsided, benzene (100 ml) and p-toluenesulfonic acid (0.2 g) were added and the reaction flask fitted with a Dean–Stark trap and condenser. The solution was refluxed until no water was collected in the trap. The solid obtained was recrystallized from benzene dried in vacuo, yield 2.1 g (11%), m.p. 403.5–404.0 K. NMR (250 MHz) (CDCl₃): 4.30 (t, J = 5 Hz), 3.27 (s), 2.86 (t, J = 5 Hz), 2.0 (m). Mass spectrum: 264,133, 132, 114, 89, 88, 87, 61, 46, 45. IR (ATR): 2964 (m), 1722 (s), 1460 (w), 1419 (m), 1376 (w), 1273 (m) 1220 (m), 1178 (m), 1127 (s), 1058 (m), 1015 (m), 951 (w), 876 (w), 847 (w), 797 (w), 740 (w), 713 (w). A crystal suitable for X-ray work were obtained from acetonitrile and mounted on a glass fiber using the oil-drop method (Kottke & Stalke, 1993) and data were collected at 193 K.

S3. Refinement

The intensity data were corrected for Lorentz and polarization effects and for absorption. All non-H atoms were refined anisotropically. H atoms were located from difference Fourier maps and were refined isotropically.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1993a); cell refinement: TEXSAN (Molecular Structure Corporation, 1993b); data reduction: TEXSAN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick, 1994); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. View of the title molecule. The displacement ellipsoids are drawn at the 30% probability level.

(I)

Crystal data

C10H16O4S2	Z = 1
Mr = 264.35	F(000) = 140
Triclinic, P1	Dx = 1.450 Mg m^−3
a = 5.3920 (18) Å	Mo Kα radiation, λ = 0.71073 Å
b = 6.858 (3) Å	Cell parameters from 25 reflections
c = 8.960 (6) Å	θ = 3.5–7.5°
α = 71.88 (4)°	µ = 0.44 mm^−1
β = 74.04 (3)°	T = 193 K
γ = 85.41 (4)°	Plate, colorless
V = 302.8 (3) Å^3	0.40 × 0.37 × 0.20 mm

Data collection

Rigaku AFC-7S diffractometer	1017 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.076
Graphite monochromator	θmax = 25.2°, θmin = 3.1°
ω/2θ scans	h = −6→6
Absorption correction: ψ scan (North et al., 1968)	k = −8→8
Tmin = 0.885, Tmax = 1.000	l = −10→10
2360 measured reflections	3 standard reflections every 200 reflections
1082 independent reflections	intensity decay: −0.1%

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.129	All H-atom parameters refined
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0741P)^2 + 0.1359P] where P = (Fo^2 + 2Fc^2)/3
1082 reflections	(Δ/σ)max < 0.001
105 parameters	Δρmax = 0.42 e Å^−3
0 restraints	Δρmin = −0.59 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
S1	0.23774 (10)	0.32376 (8)	0.93150 (7)	0.0339 (3)
C2	0.3355 (4)	0.1144 (3)	0.8452 (3)	0.0300 (5)
H2A	0.278 (5)	−0.008 (4)	0.936 (4)	0.031 (6)*
H2B	0.522 (6)	0.113 (4)	0.805 (4)	0.041 (7)*
C3	0.2011 (4)	0.1243 (3)	0.7160 (3)	0.0271 (5)
O4	0.3425 (3)	0.2284 (3)	0.5675 (2)	0.0346 (4)
C5	0.2336 (5)	0.2514 (4)	0.4309 (3)	0.0342 (6)
H5A	0.049 (6)	0.254 (4)	0.467 (4)	0.045 (8)*
H5B	0.287 (6)	0.132 (5)	0.393 (4)	0.045 (8)*
C6	0.3355 (4)	0.4494 (4)	0.3022 (3)	0.0330 (5)
H6A	0.279 (5)	0.561 (4)	0.350 (4)	0.040 (7)*
H6B	0.252 (6)	0.466 (5)	0.215 (5)	0.059 (9)*
C7	0.6307 (4)	0.4529 (3)	0.2375 (3)	0.0319 (5)
H7A	0.690 (6)	0.338 (5)	0.193 (4)	0.048 (8)*
H7B	0.708 (6)	0.433 (4)	0.325 (4)	0.044 (8)*
O8	−0.0088 (3)	0.0500 (3)	0.7408 (2)	0.0435 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0345 (4)	0.0308 (4)	0.0321 (5)	−0.0044 (3)	0.0001 (3)	−0.0103 (3)
C2	0.0264 (11)	0.0253 (11)	0.0351 (14)	0.0001 (8)	−0.0058 (10)	−0.0066 (10)
C3	0.0249 (10)	0.0207 (10)	0.0336 (13)	0.0013 (8)	−0.0049 (9)	−0.0082 (9)
O4	0.0284 (8)	0.0408 (9)	0.0310 (10)	−0.0117 (7)	−0.0054 (7)	−0.0052 (8)
C5	0.0317 (12)	0.0387 (13)	0.0337 (15)	−0.0072 (10)	−0.0085 (10)	−0.0112 (11)
C6	0.0295 (12)	0.0326 (12)	0.0352 (14)	−0.0016 (9)	−0.0067 (10)	−0.0090 (11)
C7	0.0307 (11)	0.0266 (11)	0.0350 (14)	0.0004 (9)	−0.0032 (10)	−0.0094 (10)
O8	0.0323 (9)	0.0510 (11)	0.0417 (12)	−0.0162 (8)	−0.0061 (8)	−0.0055 (9)

Geometric parameters (Å, º)

S1—C7^i	1.812 (3)	C5—H5A	0.96 (3)
S1—C2	1.812 (2)	C5—H5B	0.97 (3)
C2—C3	1.508 (3)	C6—C7	1.536 (3)
C2—H2A	0.97 (3)	C6—H6A	0.98 (3)
C2—H2B	0.97 (3)	C6—H6B	0.97 (4)
C3—O8	1.214 (3)	C7—S1^i	1.812 (3)
C3—O4	1.341 (3)	C7—H7A	0.99 (3)
O4—C5	1.459 (3)	C7—H7B	0.96 (3)
C5—C6	1.507 (4)
C7^i—S1—C2	102.91 (12)	C6—C5—H5B	112.4 (19)
C3—C2—S1	111.21 (14)	H5A—C5—H5B	109 (2)
C3—C2—H2A	108.8 (15)	C5—C6—C7	113.0 (2)
S1—C2—H2A	104.2 (15)	C5—C6—H6A	107.6 (17)
C3—C2—H2B	112.3 (18)	C7—C6—H6A	110.0 (16)
S1—C2—H2B	110.3 (16)	C5—C6—H6B	106 (2)
H2A—C2—H2B	110 (2)	C7—C6—H6B	111 (2)
O8—C3—O4	123.5 (2)	H6A—C6—H6B	108 (2)
O8—C3—C2	125.2 (2)	C6—C7—S1^i	115.03 (17)
O4—C3—C2	111.31 (18)	C6—C7—H7A	110.8 (17)
C3—O4—C5	117.05 (18)	S1^i—C7—H7A	103.3 (19)
O4—C5—C6	107.84 (18)	C6—C7—H7B	109.6 (19)
O4—C5—H5A	109.3 (19)	S1^i—C7—H7B	111.8 (19)
C6—C5—H5A	110.8 (18)	H7A—C7—H7B	106 (2)
O4—C5—H5B	106.9 (18)
C7^i—S1—C2—C3	−66.99 (18)	C3—O4—C5—C6	150.67 (19)
S1—C2—C3—O8	−86.9 (2)	O4—C5—C6—C7	61.0 (3)
S1—C2—C3—O4	92.61 (19)	C5—C6—C7—S1^i	174.15 (16)
O8—C3—O4—C5	0.1 (3)	S1—C2—C3—O4	92.61 (19)
C2—C3—O4—C5	−179.42 (17)	C3—O4—C5—C6	150.67 (19)

Symmetry code: (i) −x+1, −y+1, −z+1.