Crystal structure of 2-cyano-3,3-bis-(ethyl-sulfan-yl)-N-o-tolyl-acryl-amide.

In the mol-ecule of the title compound, C15H18N2OS2, the central S2C=C(CN)C moiety is planar (r.m.s. deviation = 0.029 Å). The C=O and C-CN groups are trans to each other across their common C-C bond. In the crystal, one classical and two 'weak' hydrogen bonds combine with borderline N⋯N and S⋯S contacts to form layers parallel to (10-2). One ethyl group is disordered over two positions with relative occupancy 0.721/0.279 (7).

Chemical context

The synthesis of ketene S,S-acetals as potential starting materials for the preparation of novel classes of heterocycles has attracted much attention (Elgemeie et al. 2009 ▸, 2015 ▸). As part of a research program for preparing new classes of anti­metabolites (Elgemeie et al. 2016 ▸, 2017a ▸), we have recently reported successful approaches for syntheses of pyridine, pyrimidine and mercaptopurine analogues by the reaction of cyano­ketene di­thio­acetals with active methyl­ene compounds (Elgemeie et al., 2003 ▸, 2006 ▸, 2017b ▸). In a continuation of this research, we report here a novel cyano­ketene di­thio­acetal (1). Product (1) was prepared by the reaction of 2-cyano-N-(o-tol­yl)acetamide with carbon di­sulfide in the presence of sodium ethoxide followed by alkyl­ation with ethyl iodide. The structure of (1) was originally based on its spectroscopic data and elemental analysis (see Experimental). In order to establish the structure of the compound unambiguously, the crystal structure was determined.

Structural commentary

The X-ray analysis confirms the exclusive presence of the form (1) in the solid state (Fig. 1 ▸). Mol­ecular dimensions may be regarded as normal [e.g. C9—C10 1.3781 (16) and C9—C11 1.4290 (16) Å]. The mol­ecular backbone C1, N1, C8, C9, C10, S1, S2 is planar to within an r.m.s. deviation of 0.029 Å; O1 deviates by 0.063 (1) and C11 by 0.284 (1) Å from this plane. The aromatic ring subtends an angle of 53.30 (3)° with the same plane. The C=O and C—CN groups are trans to each other across the C8—C9 bond, with a torsion angle of 167.61 (11)°.

Figure 1

The structure of compound (1) in the crystal, with ellipsoids at the 50% probability level. Only one position of the disordered ethyl group C14/C15 is shown.

Supra­molecular features

Hydrogen bonds are given in Table 1 ▸, where the operators are also defined. The classical hydrogen bond N1—H01⋯N2i connects the mol­ecules across inversion centres; associated with this inter­action, the N2 atoms of both mol­ecules are forced into a close contact of 3.061 (2) Å. Two further contacts (C—H⋯N and C—H⋯O; Table 1 ▸) may reasonably be regarded as ‘weak’ hydrogen bonds on the basis of distance and approximately linear angles at the relevant hydrogen atoms. Finally, a borderline contact S1⋯S2ii of 3.7488 (4) Å is observed. All these secondary inter­actions combine to form a layer of mol­ecules parallel to (10) (Fig. 2 ▸).

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H01⋯N2i	0.817 (17)	2.375 (17)	3.1346 (15)	155.0 (15)
C12—H12A⋯N2ii	0.99	2.51	3.4628 (16)	160
C5—H5⋯O1iii	0.95	2.50	3.4110 (15)	161

Symmetry codes: (i) ; (ii) ; (iii) .

Figure 2

Packing diagram of compound (1) viewed perpendicular to (10). Hydrogen bonds are drawn as thick dashed bonds, with other contacts (see text) as thin dashed bonds. H atoms not involved in hydrogen bonds have been omitted for clarity.

Database survey

A search of the Cambridge Database (Version 1.19; Groom & Allen, 2014 ▸; Groom et al., 2016 ▸) for the fragment (C—S)2C=C(CN)C=O gave six hits (MTBCEY, NUCFEW, SESHUT10, SESHUT11, ZAMQUZ, ZEDJEX). In all cases the C=O and C—CN groups are mutually trans, as in the title compound.

Synthesis and crystallization

2-Cyano-N-(o-tol­yl)acetamide (1 mmol) was added to a stirred solution of potassium hydroxide (2 mmol) in DMF (10 ml). After stirring for 30 min at room temperature, carbon di­sulfide (1.5 mmol) was added. The solution was left for 12 h at room temperature and then ethyl iodide (2 mmol) was added dropwise. Stirring was continued for a further 6 h. The reaction mixture was poured onto ice–water and the solid product was filtered off, dried and crystallized from ethanol to give yellow crystals, m.p. 93°C (366 K), yield 40%.

IR (KBr), 3430 (NH), 2220 (CN), 1670 (C=O) cm−1; 1H NMR (400 MHz, DMSO-d 6): δ 1.25 (t, J = 8 Hz, 3H, CH2CH 3), 1.31 (t, J = 8 Hz, 3H, CH2CH 3), 2.51 (s, 3H, CH3), 3.03 (q, J = 6.8 Hz, 2H, CH 2CH3), 3.12 (q, J = 6.8 Hz, 2H, CH 2CH3), 7.15–7.36 (m, 4H, C6H4), 10.05 (s, 1H, NH), Analysis calculated for C15H18ON2S2 (306.43): C, 58.82; H, 5.88, N, 9.15, S, 20.91%; Found: C, 58.70; H, 5.65, N, 9.00, S, 20.77%.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The ethyl group C14/15 is disordered over two positions with relative occupancy 0.721 (7)/0.279 (7). Appropriate restraints were employed to improve refinement stability, but the dimensions of disordered groups should be inter­preted with caution.

Table 2

Experimental details

Crystal data
Chemical formula	C15H18N2OS2
M r	306.43
Crystal system, space group	Monoclinic, P21/c
Temperature (K)	100
a, b, c (Å)	9.4104 (4), 12.8350 (4), 13.0774 (5)
β (°)	104.198 (4)
V (Å3)	1531.28 (10)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.35
Crystal size (mm)	0.35 × 0.35 × 0.30
Data collection
Diffractometer	Oxford Diffraction Xcalibur Eos
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015 ▸)
T min, T max	0.986, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	42164, 4682, 3985
R int	0.043
(sin θ/λ)max (Å−1)	0.728
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.034, 0.081, 1.03
No. of reflections	4682
No. of parameters	197
No. of restraints	15
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.37, −0.22

Computer programs: CrysAlis PRO (Rigaku Oxford Diffraction, 2015 ▸), SHELXS97 and SHELXL97 (Sheldrick, 2008 ▸) and XP (Siemens, 1994 ▸).

The NH hydrogen was refined freely. Methyl H atoms were refined as idealized rigid groups (C—H 0.98 Å, H—C—H 109.5°) allowed to rotate but not tip (exception: minor disorder component at C15′, set ideally staggered with AFIX 33). Other hydrogen atoms were included using a riding model starting from calculated positions, with Carom—H 0.95, Cmethyl­ene—H 0.99 Å, with U iso(H) = 1.5U eq(C-methyl) and 1.2U eq(C) for other H atoms.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989017005783/hg5488sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989017005783/hg5488Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989017005783/hg5488Isup3.cml

CCDC reference: 1544524

Additional supporting information: crystallographic information; 3D view; checkCIF report

C15H18N2OS2	F(000) = 648
Mr = 306.43	Dx = 1.329 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 10087 reflections
a = 9.4104 (4) Å	θ = 2.7–30.4°
b = 12.8350 (4) Å	µ = 0.35 mm−1
c = 13.0774 (5) Å	T = 100 K
β = 104.198 (4)°	Block, pale yellow
V = 1531.28 (10) Å3	0.35 × 0.35 × 0.30 mm
Z = 4

Oxford Diffraction Xcalibur Eos diffractometer	4682 independent reflections
Radiation source: fine-focus sealed X-ray tube	3985 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
Detector resolution: 16.1419 pixels mm-1	θmax = 31.2°, θmin = 2.2°
ω scan	h = −13→13
Absorption correction: multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015)	k = −18→18
Tmin = 0.986, Tmax = 1.000	l = −18→18
42164 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ2(Fo2) + (0.0309P)2 + 0.7259P] where P = (Fo2 + 2Fc2)/3
4682 reflections	(Δ/σ)max = 0.001
197 parameters	Δρmax = 0.37 e Å−3
15 restraints	Δρmin = −0.22 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 7.3265 (0.0012) x + 3.0782 (0.0029) y - 9.8498 (0.0015) z = 0.3852 (0.0018) * -0.0120 (0.0007) C1 * 0.0262 (0.0010) C8 * 0.0574 (0.0010) C9 * -0.0136 (0.0009) C10 * -0.0055 (0.0004) S1 * -0.0220 (0.0005) S2 * -0.0304 (0.0009) N1 0.0632 (0.0010) O1 0.2839 (0.0014) C11 Rms deviation of fitted atoms = 0.0287 8.1736 (0.0024) x - 6.3013 (0.0055) y - 3.6411 (0.0064) z = 1.1855 (0.0026) Angle to previous plane (with approximate esd) = 53.30 ( 0.03 ) * -0.0174 (0.0008) C1 * 0.0106 (0.0008) C2 * 0.0039 (0.0009) C3 * -0.0118 (0.0009) C4 * 0.0052 (0.0009) C5 * 0.0095 (0.0008) C6 Rms deviation of fitted atoms = 0.0107

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 > 2sigma(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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.48134 (12)	0.21516 (9)	0.38738 (9)	0.0144 (2)
C2	0.46128 (12)	0.24547 (9)	0.28216 (9)	0.0156 (2)
C3	0.37643 (14)	0.18128 (10)	0.20464 (9)	0.0206 (2)
H3	0.3601	0.2008	0.1326	0.025*
C4	0.31546 (14)	0.08976 (10)	0.23047 (10)	0.0222 (2)
H4	0.2564	0.0480	0.1765	0.027*
C5	0.34046 (14)	0.05902 (9)	0.33513 (10)	0.0200 (2)
H5	0.3005	−0.0045	0.3529	0.024*
C6	0.42423 (13)	0.12172 (9)	0.41347 (9)	0.0173 (2)
H6	0.4427	0.1008	0.4852	0.021*
C7	0.53257 (14)	0.34242 (10)	0.25430 (10)	0.0214 (2)
H7A	0.4999	0.4026	0.2886	0.032*
H7B	0.5051	0.3522	0.1776	0.032*
H7C	0.6393	0.3357	0.2784	0.032*
C8	0.67932 (12)	0.25551 (9)	0.54338 (9)	0.0148 (2)
C9	0.74786 (13)	0.33969 (9)	0.61750 (9)	0.0157 (2)
C10	0.86223 (13)	0.32278 (9)	0.70449 (9)	0.0156 (2)
C11	0.69858 (13)	0.44369 (9)	0.59035 (9)	0.0176 (2)
S1	0.94594 (3)	0.20139 (2)	0.72800 (2)	0.01904 (8)
C12	1.07266 (14)	0.21116 (10)	0.85705 (10)	0.0222 (2)
H12A	1.1520	0.1594	0.8617	0.027*
H12B	1.1179	0.2813	0.8647	0.027*
C13	1.00032 (18)	0.19311 (12)	0.94728 (11)	0.0324 (3)
H13A	0.9294	0.2489	0.9481	0.049*
H13B	1.0752	0.1930	1.0142	0.049*
H13C	0.9496	0.1258	0.9378	0.049*
S2	0.93498 (3)	0.42489 (2)	0.79137 (2)	0.02058 (8)
C14	0.77925 (19)	0.4973 (2)	0.81670 (17)	0.0211 (6)	0.721 (7)
H14A	0.7472	0.5518	0.7624	0.025*	0.721 (7)
H14B	0.6959	0.4496	0.8145	0.025*	0.721 (7)
C15	0.8290 (3)	0.5466 (2)	0.9252 (2)	0.0234 (5)	0.721 (7)
H15A	0.8431	0.4922	0.9793	0.035*	0.721 (7)
H15B	0.7544	0.5959	0.9358	0.035*	0.721 (7)
H15C	0.9217	0.5836	0.9306	0.035*	0.721 (7)
C14'	0.7812 (5)	0.4548 (6)	0.8430 (5)	0.0206 (13)*	0.279 (7)
H14C	0.6907	0.4573	0.7853	0.025*	0.279 (7)
H14D	0.7689	0.4007	0.8941	0.025*	0.279 (7)
C15'	0.8087 (9)	0.5593 (6)	0.8967 (7)	0.029 (2)*	0.279 (7)
H15D	0.7263	0.5771	0.9269	0.044*	0.279 (7)
H15E	0.8186	0.6125	0.8451	0.044*	0.279 (7)
H15F	0.8991	0.5563	0.9530	0.044*	0.279 (7)
N1	0.55847 (11)	0.28375 (8)	0.46806 (8)	0.0169 (2)
H01	0.5279 (18)	0.3435 (14)	0.4655 (12)	0.026 (4)*
N2	0.65583 (12)	0.52547 (8)	0.56292 (9)	0.0244 (2)
O1	0.73077 (10)	0.16749 (7)	0.55038 (7)	0.01999 (18)

	U11	U22	U33	U12	U13	U23
C1	0.0152 (5)	0.0127 (5)	0.0153 (5)	0.0007 (4)	0.0036 (4)	−0.0020 (4)
C2	0.0157 (5)	0.0146 (5)	0.0170 (5)	0.0021 (4)	0.0048 (4)	0.0008 (4)
C3	0.0233 (6)	0.0228 (6)	0.0149 (5)	0.0019 (5)	0.0032 (4)	−0.0014 (4)
C4	0.0219 (6)	0.0191 (6)	0.0236 (6)	−0.0007 (5)	0.0018 (5)	−0.0073 (5)
C5	0.0205 (6)	0.0130 (5)	0.0272 (6)	−0.0016 (4)	0.0074 (5)	−0.0019 (4)
C6	0.0208 (6)	0.0144 (5)	0.0179 (5)	0.0010 (4)	0.0071 (4)	0.0005 (4)
C7	0.0230 (6)	0.0202 (6)	0.0221 (6)	−0.0010 (5)	0.0075 (5)	0.0048 (5)
C8	0.0166 (5)	0.0134 (5)	0.0153 (5)	−0.0007 (4)	0.0055 (4)	0.0004 (4)
C9	0.0170 (5)	0.0121 (5)	0.0172 (5)	0.0008 (4)	0.0025 (4)	−0.0005 (4)
C10	0.0150 (5)	0.0141 (5)	0.0179 (5)	0.0010 (4)	0.0046 (4)	−0.0003 (4)
C11	0.0173 (5)	0.0155 (5)	0.0175 (5)	−0.0013 (4)	−0.0007 (4)	−0.0032 (4)
S1	0.02006 (15)	0.01621 (14)	0.01943 (14)	0.00640 (11)	0.00213 (11)	−0.00021 (10)
C12	0.0184 (6)	0.0217 (6)	0.0232 (6)	0.0053 (5)	−0.0010 (4)	0.0018 (5)
C13	0.0391 (8)	0.0344 (8)	0.0218 (6)	0.0005 (6)	0.0036 (6)	0.0036 (6)
S2	0.01549 (14)	0.01860 (15)	0.02518 (15)	0.00178 (10)	0.00028 (11)	−0.00709 (11)
C14	0.0192 (9)	0.0211 (12)	0.0238 (9)	0.0043 (7)	0.0069 (6)	−0.0028 (8)
C15	0.0326 (12)	0.0214 (10)	0.0185 (11)	0.0020 (8)	0.0105 (10)	−0.0036 (9)
N1	0.0210 (5)	0.0107 (4)	0.0167 (4)	0.0021 (4)	0.0001 (4)	−0.0014 (4)
N2	0.0239 (6)	0.0151 (5)	0.0278 (5)	−0.0002 (4)	−0.0061 (4)	−0.0021 (4)
O1	0.0224 (4)	0.0132 (4)	0.0227 (4)	0.0037 (3)	0.0025 (3)	−0.0014 (3)

C1—C6	1.3905 (16)	C3—H3	0.9500
C1—C2	1.3975 (15)	C4—H4	0.9500
C1—N1	1.4282 (14)	C5—H5	0.9500
C2—C3	1.3953 (16)	C6—H6	0.9500
C2—C7	1.5004 (16)	C7—H7A	0.9800
C3—C4	1.3850 (18)	C7—H7B	0.9800
C4—C5	1.3879 (18)	C7—H7C	0.9800
C5—C6	1.3865 (17)	C12—H12A	0.9900
C8—O1	1.2236 (14)	C12—H12B	0.9900
C8—N1	1.3585 (15)	C13—H13A	0.9800
C8—C9	1.4888 (16)	C13—H13B	0.9800
C9—C10	1.3781 (16)	C13—H13C	0.9800
C9—C11	1.4290 (16)	C14—H14A	0.9900
C10—S1	1.7390 (12)	C14—H14B	0.9900
C10—S2	1.7594 (12)	C15—H15A	0.9800
C11—N2	1.1496 (16)	C15—H15B	0.9800
S1—C12	1.8162 (13)	C15—H15C	0.9800
C12—C13	1.518 (2)	C14'—H14C	0.9900
S2—C14'	1.783 (5)	C14'—H14D	0.9900
S2—C14	1.8326 (18)	C15'—H15D	0.9800
C14—C15	1.519 (3)	C15'—H15E	0.9800
C14'—C15'	1.507 (9)	C15'—H15F	0.9800
N1—H01	0.817 (17)
C6—C1—C2	120.98 (10)	C2—C7—H7A	109.5
C6—C1—N1	120.49 (10)	C2—C7—H7B	109.5
C2—C1—N1	118.50 (10)	H7A—C7—H7B	109.5
C3—C2—C1	117.77 (11)	C2—C7—H7C	109.5
C3—C2—C7	121.57 (11)	H7A—C7—H7C	109.5
C1—C2—C7	120.63 (10)	H7B—C7—H7C	109.5
C4—C3—C2	121.40 (11)	C13—C12—H12A	108.9
C3—C4—C5	120.10 (11)	S1—C12—H12A	108.9
C6—C5—C4	119.46 (11)	C13—C12—H12B	108.9
C5—C6—C1	120.21 (11)	S1—C12—H12B	108.9
O1—C8—N1	123.11 (11)	H12A—C12—H12B	107.7
O1—C8—C9	121.40 (10)	C12—C13—H13A	109.5
N1—C8—C9	115.49 (10)	C12—C13—H13B	109.5
C10—C9—C11	119.50 (10)	H13A—C13—H13B	109.5
C10—C9—C8	123.30 (10)	C12—C13—H13C	109.5
C11—C9—C8	116.99 (10)	H13A—C13—H13C	109.5
C9—C10—S1	121.02 (9)	H13B—C13—H13C	109.5
C9—C10—S2	121.14 (9)	C15—C14—H14A	110.2
S1—C10—S2	117.75 (7)	S2—C14—H14A	110.2
N2—C11—C9	176.23 (12)	C15—C14—H14B	110.2
C10—S1—C12	105.56 (6)	S2—C14—H14B	110.2
C13—C12—S1	113.23 (10)	H14A—C14—H14B	108.5
C10—S2—C14'	100.46 (17)	C15'—C14'—H14C	110.1
C10—S2—C14	107.01 (7)	S2—C14'—H14C	110.1
C15—C14—S2	107.65 (16)	C15'—C14'—H14D	110.1
C15'—C14'—S2	107.8 (5)	S2—C14'—H14D	110.1
C8—N1—C1	123.68 (10)	H14C—C14'—H14D	108.5
C4—C3—H3	119.3	C14'—C15'—H15D	109.5
C2—C3—H3	119.3	C14'—C15'—H15E	109.5
C3—C4—H4	120.0	H15D—C15'—H15E	109.5
C5—C4—H4	120.0	C14'—C15'—H15F	109.5
C6—C5—H5	120.3	H15D—C15'—H15F	109.5
C4—C5—H5	120.3	H15E—C15'—H15F	109.5
C5—C6—H6	119.9	C8—N1—H01	120.2 (11)
C1—C6—H6	119.9	C1—N1—H01	116.0 (11)
C6—C1—C2—C3	2.91 (17)	C11—C9—C10—S2	7.34 (16)
N1—C1—C2—C3	−175.34 (11)	C8—C9—C10—S2	−178.08 (9)
C6—C1—C2—C7	−175.44 (11)	C9—C10—S1—C12	−173.24 (10)
N1—C1—C2—C7	6.31 (16)	S2—C10—S1—C12	10.20 (9)
C1—C2—C3—C4	−0.85 (18)	C10—S1—C12—C13	83.40 (11)
C7—C2—C3—C4	177.48 (12)	C9—C10—S2—C14'	64.9 (3)
C2—C3—C4—C5	−1.27 (19)	S1—C10—S2—C14'	−118.6 (3)
C3—C4—C5—C6	1.35 (19)	C9—C10—S2—C14	44.96 (14)
C4—C5—C6—C1	0.68 (18)	S1—C10—S2—C14	−138.48 (11)
C2—C1—C6—C5	−2.86 (18)	C10—S2—C14—C15	152.32 (19)
N1—C1—C6—C5	175.35 (11)	C14'—S2—C14—C15	78.5 (5)
O1—C8—C9—C10	−7.09 (18)	C10—S2—C14'—C15'	−164.9 (5)
N1—C8—C9—C10	173.60 (11)	C14—S2—C14'—C15'	−53.9 (6)
O1—C8—C9—C11	167.61 (11)	O1—C8—N1—C1	−1.97 (18)
N1—C8—C9—C11	−11.70 (15)	C9—C8—N1—C1	177.32 (10)
C11—C9—C10—S1	−169.10 (9)	C6—C1—N1—C8	57.60 (16)
C8—C9—C10—S1	5.47 (16)	C2—C1—N1—C8	−124.15 (12)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H01···N2i	0.817 (17)	2.375 (17)	3.1346 (15)	155.0 (15)
C12—H12A···N2ii	0.99	2.51	3.4628 (16)	160
C5—H5···O1iii	0.95	2.50	3.4110 (15)	161