Ethyl 2-cyano-2-(1,3-dithiepan-2-yl­idene)acetate

Benmilat, A.; Bouraoui, H.; Chetioui, S.; Hamdouni, N.; Boudjada, A.

doi:10.1107/S2414314625011423

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 10| Part 12| December 2025| x251142

https://doi.org/10.1107/S2414314625011423

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Ethyl 2-cyano-2-(1,3-dithiepan-2-ylidene)acetate

Ahmed Benmilat,^a Hazem Bouraoui,^a,^b Souheyla Chetioui,^c,^d ^* Noudjoud Hamdouni ^a and Ali Boudjada ^a

^aLaboratoire de Cristallographie, Département de Physique, Université des Frères Mentouri-Constantine, 25000 Constantine, Algeria, ^bUniv. Ouargla, Faculté des Hydrocarbures, des Energies Renouvelables, des Sciences de la Terre et de l'Univers, route de Ghardaia, Ouargla 30000, Algeria, ^cVEHDD Laboratory. University of M'sila. University Pole, Road Bourdj Bou Arreiridj, 28000 M'sila, Algeria, and ^dResearch Unit for Chemistry of the Environment and Molecular Structural, University of Constantine 1, Constantine 25000, Algeria
^*Correspondence e-mail: [email protected]

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 27 November 2025; accepted 18 December 2025; online 24 December 2025)

In the title compound, C₁₀H₁₃NO₂S₂, the seven-membered 1,3-dithiepane ring adopts a distorted chair conformation. In the extended structure, inversion dimers linked by pairwise C—H⋯O hydrogen bonds generate R₂²(14) loops.

Keywords: crystal structure; Hirshfeld surface analysis.

CCDC reference: 2517231

Structure description

The title compound, C₁₀H₁₃NO₂S₂, is commercially available. It crystallizes in the triclinic space group P $[\overline{1}]$ with one molecule in the asymmetric unit (Fig. 1). The seven-membered heterocyclic ring adopts a distorted chair conformation with C4/C6/C7/S1/S2 roughly coplanar (r.m.s. deviation = 0.207 Å) and C5 and C8 deviating from their best plane by −0.849 (3) and 0.869 (3) Å, respectively. The C4—S1 [1.746 (2) Å] and C4—S3 [1.733 (2) Å] bond lengths show slight asymmetry. The cyanide group and O1 have an anti orientation [O1—C1—C2—C3 = 174.1 (2)°] and the ester chain is extended [C1—O2—C9—C10 = −179.4 (2)°]. In the extended structure, inversion dimers linked by pairwise C8—H8B⋯O1 hydrogen bonds (Table 1) generate R₂²(14) loops (Fig. 2). Otherwise, there are no notable short contacts.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8B⋯O1ⁱ	0.95 (3)	2.58 (3)	3.484 (3)	160 (2)
Symmetry code: (i) .

Figure 1
The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level.

Figure 2
An inversion dimer in the extended structure of the title compound linked by pairwise C—H⋯O hydrogn bonds.

The program CrystalExplorer (Turner et al., 2017 ) was used to generate the Hirshfeld surface (supplementary Fig. 1) and two-dimensional fingerprint plots for the title compound. The full two-dimensional fingerprint plot for the title compound is given in Fig. 3(a) and the different contact types are shown in Fig. 3(b)–(f). The greatest contribution to the overall Hirshfeld surface is due to H⋯H contacts, which contribute 40.4%, followed by H⋯O/O⋯H (15.9%), N⋯H/H⋯N (15.8%), H⋯S/S⋯H (12.1%) while S⋯S gives a small contribution of 1.3%.

Figure 3
(a) The full two-dimensional Hirshfeld fingerprint plot for the title compound and those delineated into (b) O⋯H/H⋯O, (c) S⋯S, (d) N⋯H/H⋯N, (e) H⋯H and (f) H⋯S/S⋯H contacts.

Synthesis and crystallization

The title compound, obtained commercially, was recrystallized from ethanol solution, yielding colorless prismatic crystals suitable for single-crystal X-ray diffraction analysis.

Refinement

Crystallographic data and refinement parameters for the title compound are given in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₀H₁₃NO₂S₂
M_r	243.33
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	293
a, b, c (Å)	6.4761 (8), 9.5708 (11), 10.6436 (12)
α, β, γ (°)	71.347 (10), 78.799 (10), 71.986 (11)
V (Å³)	591.08 (13)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.43
Crystal size (mm)	0.5 × 0.29 × 0.15

Data collection
Diffractometer	Xcalibur, Eos
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2013 )
T_min, T_max	0.986, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3567, 2274, 1684
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.098, 0.99
No. of reflections	2274
No. of parameters	152
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.20
Computer programs: CrysAlis PRO (Agilent, 2013), SHELXT (Sheldrick, 2015a ), SHELXL2014/7 (Sheldrick, 2015b ), OLEX2 (Dolomanov et al., 2009 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 2517231

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314625011423/hb4547sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314625011423/hb4547Isup2.hkl

Table. DOI: https://doi.org/10.1107/S2414314625011423/hb4547sup3.docx

Hirshfeld surface. DOI: https://doi.org/10.1107/S2414314625011423/hb4547sup4.docx

Supporting information file. DOI: https://doi.org/10.1107/S2414314625011423/hb4547Isup5.cml

checkCIF report

Computing details top

Ethyl 2-cyano-2-(1,3-dithiepan-2-ylidene)acetate top

Crystal data top

C₁₀H₁₃NO₂S₂	Z = 2
M_r = 243.33	F(000) = 256
Triclinic, P1	D_x = 1.367 Mg m⁻³
a = 6.4761 (8) Å	Mo Kα radiation, λ = 0.7107 Å
b = 9.5708 (11) Å	Cell parameters from 1290 reflections
c = 10.6436 (12) Å	θ = 3.7–26.3°
α = 71.347 (10)°	µ = 0.43 mm⁻¹
β = 78.799 (10)°	T = 293 K
γ = 71.986 (11)°	Needle, yellow
V = 591.08 (13) Å³	0.5 × 0.29 × 0.15 mm

Data collection top

Xcalibur, Eos diffractometer	2274 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1684 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.029
Detector resolution: 8.0226 pixels mm^-1	θ_max = 27.5°, θ_min = 3.5°
ω scans	h = −7→8
Absorption correction: multi-scan (CrysAlisPro; Agilent, 2013)	k = −11→12
T_min = 0.986, T_max = 1.000	l = −12→13
3567 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.042	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.098	w = 1/[σ²(F_o²) + (0.0459P)²] where P = (F_o² + 2F_c²)/3
S = 0.99	(Δ/σ)_max = 0.001
2274 reflections	Δρ_max = 0.21 e Å⁻³
152 parameters	Δρ_min = −0.20 e Å⁻³
0 restraints

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

Refinement. The H atoms attached to C5 and C8 were freely refined. The other b H atoms were included in calculated positions and treated as riding (C—H = 0.95–0.98 Å) with U_iso(H) = 1.2U_eq(C) or 1.5U_eq(methyl C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.84626 (9)	0.63684 (6)	0.37317 (6)	0.0493 (2)
S3	0.54520 (10)	0.86994 (6)	0.17303 (6)	0.0526 (2)
O1	0.3040 (3)	0.70355 (19)	0.11035 (17)	0.0592 (6)
O2	0.3664 (2)	0.44937 (17)	0.19391 (15)	0.0495 (5)
N1	0.6992 (4)	0.2995 (2)	0.4281 (2)	0.0666 (8)
C1	0.3971 (3)	0.5847 (3)	0.1832 (2)	0.0412 (7)
C2	0.5574 (3)	0.5687 (2)	0.27179 (19)	0.0379 (7)
C3	0.6340 (3)	0.4190 (3)	0.3604 (2)	0.0442 (8)
C4	0.6379 (3)	0.6850 (2)	0.27224 (19)	0.0381 (7)
C5	0.7925 (5)	0.7955 (3)	0.4434 (3)	0.0614 (10)
C6	0.8948 (5)	0.9230 (3)	0.3654 (3)	0.0768 (11)
C7	0.7828 (5)	1.0306 (3)	0.2451 (3)	0.0806 (11)
C8	0.7696 (5)	0.9547 (3)	0.1443 (3)	0.0602 (10)
C9	0.2088 (4)	0.4526 (3)	0.1127 (2)	0.0534 (8)
C10	0.1962 (5)	0.2933 (3)	0.1393 (3)	0.0743 (11)
H5A	0.851 (4)	0.744 (3)	0.527 (2)	0.0631*
H5B	0.634 (4)	0.837 (3)	0.457 (2)	0.057 (7)*
H6A	0.89577	0.98185	0.42431	0.0922*
H6B	1.04552	0.87868	0.33590	0.0922*
H7A	0.86041	1.10835	0.20172	0.0968*
H7B	0.63584	1.08175	0.27513	0.0968*
H8A	0.903 (5)	0.880 (3)	0.126 (3)	0.086 (9)*
H8B	0.744 (4)	1.032 (3)	0.063 (3)	0.076 (8)*
H9A	0.06691	0.51712	0.13520	0.0640*
H9B	0.25414	0.49338	0.01901	0.0640*
H10A	0.15400	0.25341	0.23249	0.1116*
H10B	0.08997	0.29244	0.08811	0.1116*
H10C	0.33632	0.23112	0.11444	0.1116*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0545 (4)	0.0433 (3)	0.0528 (4)	−0.0111 (3)	−0.0257 (3)	−0.0071 (3)
S3	0.0595 (4)	0.0374 (3)	0.0624 (4)	−0.0137 (3)	−0.0307 (3)	−0.0011 (3)
O1	0.0602 (10)	0.0468 (10)	0.0693 (11)	−0.0136 (8)	−0.0301 (8)	−0.0016 (8)
O2	0.0539 (9)	0.0415 (9)	0.0615 (10)	−0.0106 (7)	−0.0250 (7)	−0.0166 (8)
N1	0.0785 (15)	0.0467 (13)	0.0755 (15)	−0.0181 (11)	−0.0331 (12)	−0.0024 (12)
C1	0.0392 (12)	0.0443 (13)	0.0411 (12)	−0.0115 (10)	−0.0061 (9)	−0.0119 (10)
C2	0.0398 (12)	0.0373 (12)	0.0360 (11)	−0.0083 (9)	−0.0066 (9)	−0.0096 (9)
C3	0.0448 (13)	0.0435 (14)	0.0475 (13)	−0.0124 (10)	−0.0104 (10)	−0.0130 (11)
C4	0.0402 (12)	0.0395 (12)	0.0339 (11)	−0.0078 (9)	−0.0075 (9)	−0.0099 (9)
C5	0.076 (2)	0.0617 (17)	0.0597 (17)	−0.0202 (15)	−0.0262 (14)	−0.0215 (14)
C6	0.094 (2)	0.0581 (17)	0.096 (2)	−0.0284 (15)	−0.0491 (17)	−0.0145 (16)
C7	0.096 (2)	0.0506 (16)	0.110 (2)	−0.0331 (15)	−0.0535 (18)	−0.0041 (16)
C8	0.0656 (18)	0.0481 (15)	0.0631 (18)	−0.0256 (14)	−0.0199 (14)	0.0075 (13)
C9	0.0493 (13)	0.0630 (16)	0.0568 (15)	−0.0130 (12)	−0.0194 (11)	−0.0225 (13)
C10	0.089 (2)	0.0657 (18)	0.087 (2)	−0.0281 (15)	−0.0379 (16)	−0.0226 (16)

Geometric parameters (Å, º) top

S1—C4	1.746 (2)	C9—C10	1.484 (4)
S1—C5	1.812 (3)	C5—H5A	0.96 (2)
S3—C4	1.733 (2)	C5—H5B	0.98 (3)
S3—C8	1.806 (3)	C6—H6A	0.9700
O1—C1	1.205 (3)	C6—H6B	0.9700
O2—C1	1.337 (3)	C7—H7A	0.9700
O2—C9	1.448 (3)	C7—H7B	0.9700
N1—C3	1.139 (3)	C8—H8A	0.97 (3)
C1—C2	1.476 (3)	C8—H8B	0.95 (3)
C2—C3	1.437 (3)	C9—H9A	0.9700
C2—C4	1.369 (3)	C9—H9B	0.9700
C5—C6	1.502 (4)	C10—H10A	0.9600
C6—C7	1.510 (4)	C10—H10B	0.9600
C7—C8	1.503 (4)	C10—H10C	0.9600

C4—S1—C5	105.61 (12)	C7—C6—H6A	109.00
C4—S3—C8	105.23 (12)	C7—C6—H6B	109.00
C1—O2—C9	115.77 (18)	H6A—C6—H6B	108.00
O1—C1—O2	123.6 (2)	C6—C7—H7A	109.00
O1—C1—C2	125.1 (2)	C6—C7—H7B	109.00
O2—C1—C2	111.30 (19)	C8—C7—H7A	109.00
C1—C2—C3	116.38 (19)	C8—C7—H7B	109.00
C1—C2—C4	124.33 (19)	H7A—C7—H7B	108.00
C3—C2—C4	119.28 (19)	S3—C8—H8A	108.1 (19)
N1—C3—C2	178.2 (2)	S3—C8—H8B	103.0 (17)
S1—C4—S3	121.36 (12)	C7—C8—H8A	114.1 (19)
S1—C4—C2	116.79 (15)	C7—C8—H8B	107.2 (18)
S3—C4—C2	121.81 (16)	H8A—C8—H8B	106 (3)
S1—C5—C6	116.7 (2)	O2—C9—H9A	110.00
C5—C6—C7	114.9 (3)	O2—C9—H9B	110.00
C6—C7—C8	114.5 (2)	C10—C9—H9A	110.00
S3—C8—C7	117.2 (2)	C10—C9—H9B	110.00
O2—C9—C10	107.7 (2)	H9A—C9—H9B	108.00
S1—C5—H5A	100.8 (17)	C9—C10—H10A	109.00
S1—C5—H5B	108.1 (16)	C9—C10—H10B	109.00
C6—C5—H5A	111.1 (17)	C9—C10—H10C	109.00
C6—C5—H5B	109.3 (15)	H10A—C10—H10B	109.00
H5A—C5—H5B	111 (2)	H10A—C10—H10C	110.00
C5—C6—H6A	109.00	H10B—C10—H10C	109.00
C5—C6—H6B	109.00

C4—S1—C5—C6	−90.0 (3)	O2—C1—C2—C4	173.05 (19)
C5—S1—C4—C2	−141.98 (18)	O1—C1—C2—C4	−7.2 (4)
C5—S1—C4—S3	40.31 (17)	O2—C1—C2—C3	−5.7 (3)
C8—S3—C4—S1	24.32 (17)	C3—C2—C4—S1	4.9 (3)
C4—S3—C8—C7	−88.0 (2)	C1—C2—C4—S3	3.9 (3)
C8—S3—C4—C2	−153.28 (18)	C3—C2—C4—S3	−177.39 (16)
C1—O2—C9—C10	−179.4 (2)	C1—C2—C4—S1	−173.78 (16)
C9—O2—C1—C2	178.94 (17)	S1—C5—C6—C7	76.9 (3)
C9—O2—C1—O1	−0.9 (3)	C5—C6—C7—C8	−58.4 (4)
O1—C1—C2—C3	174.1 (2)	C6—C7—C8—S3	84.3 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8B···O1ⁱ	0.95 (3)	2.58 (3)	3.484 (3)	160 (2)

Symmetry code: (i) −x+1, −y+2, −z.

Acknowledgements

This work was supported by the Laboratoire de Cristallographie, Departement de Physique, Universite Constantine 1, Algeria. We thank Mr F. Saidi, Engineer at the Laboratory of Crystallography, University Constantine 1, for assistance in collecting data on the Xcalibur X-ray diffractometer.

References

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