(±)-(rel-3R,3′R)-1,1′-Dimethyl-3,3′-bipyrrolidine-2,2′-dithione

Madeley, L.G.; Lemmerer, A.; Michael, J.P.

doi:10.1107/S1600536812043498

organic compounds

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ISSN: 2056-9890

Volume 68| Part 11| November 2012| Page o3211

doi:10.1107/S1600536812043498

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(±)-(rel-3R,3′R)-1,1′-Dimethyl-3,3′-bipyrrolidine-2,2′-dithione

Lee G. Madeley,^a Andreas Lemmerer ^a and Joseph P. Michael ^a ^*

^aMolecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, PO Wits, 2050 Johannesburg, South Africa
^*Correspondence e-mail: joseph.michael@wits.ac.za

(Received 17 October 2012; accepted 19 October 2012; online 27 October 2012)

The asymmetric unit of the racemic title compound, C₁₀H₁₆N₂S₂, a C₂-symmetric bis(thiolactam), contains one half-molecule, the complete molecule being generated by a twofold axis symmetry operation. The five-membered ring is nearly planar, with a maximum deviation of 0.025 (1) Å. In the crystal, the molecules are linked via weak C—H⋯S interactions, forming infinite chains along the b-axis direction.

Related literature

For related synthesis, see: Tamaru et al. (1978 ); Schroth et al. (2000 ).

Experimental

Crystal data

C₁₀H₁₆N₂S₂
M_r = 228.37
Monoclinic, C 2/c
a = 20.520 (3) Å
b = 5.7237 (7) Å
c = 11.220 (2) Å
β = 122.009 (5)°
V = 1117.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.44 mm⁻¹
T = 173 K
0.45 × 0.42 × 0.16 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.827, T_max = 0.933
1759 measured reflections
1022 independent reflections
957 reflections with I > 2σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.077
S = 1.09
1022 reflections
65 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5B⋯S1ⁱ	0.98	2.98	3.8373 (18)	146
Symmetry code: (i) x, y-1, z.

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT-Plus (Bruker, 2004 ); data reduction: SAINT-Plus and XPREP (Bruker 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ) and DIAMOND (Brandenburg, 1999 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ) and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812043498/bt6851sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812043498/bt6851Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812043498/bt6851Isup3.mol

Supporting information file. DOI: 10.1107/S1600536812043498/bt6851Isup4.cml

checkCIF report

Comment top

The title compound, (±)-(rel-3R,3'R)-1,1'-dimethyl-3,3'- bipyrrolidine-2,2'-dithione, was obtained as a minor product from the attempted S_RN1 arylation of deprotonated 1-methylpyrrolidine-2-thione with 4-bromoanisole under photolytic conditions. Previous workers had reported the same dimer from the reaction of deprotonated 1-methylpyrrolidine-2-thione with molecular iodine – apparently incorrectly as the meso diastereomer (Tamaru et al., 1978), later corrected to the C₂-symmetric isomer (Schroth et al., 2000).

The asymmetric unit of the title compound consists of half a molecule around a twofold axis, and Fig. 1 shows the atomic numbering scheme. The complete molecule is generated by the twofold axis. Both stereogenic centres have the same relative configuration, which is depicted in Fig. 1 as rel-(R,R'). The opposite enantiomer in the crystal is generated by the c-glide in C2/c. The hydrogen bonding of the title compound consists of weak C—H···S hydrogen bonds from the methyl group to generate hydrogen bonded chains along the b-axis by unit cell translations only (Fig. 2).

Related literature top

For related synthesis, see: Tamaru et al. (1978); Schroth et al. (2000).

Experimental top

A solution of 1-methylpyrrolidine-2-thione (580 mg, 5.5 mmol) in dry tetrahydrofuran (20 ml) was treated at 0 °C with a solution of n-butyllithium in hexane (5.5 mol). After 20 min 4-bromoanisole (690 µl, 5.5 mmol) was added, and the solution was irradiated for 30 min with a mercury lamp (125 W). The reaction mixture was poured into aq. NH₄Cl solution, and the organic components were extracted with dichloromethane. Chromatography of the residue on silica gel after evaporation of the solvent returned unreacted 4-bromoanisole (50%), thiolactam (38%) and (±)-(rel-3R,3'R)-1,1'- dimethyl-3,3'-bipyrrolidine-2,2'-dithione (104 mg, 18%). The product was recrystallized from acetone to give colourless cubes, m.p. 476–477 K.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The asymmetric unit of (I) showing the atomic numbering scheme. Displacement ellipsoids are shown at the 50% probability level. Atoms with superscript (i) are at the symmetry position (-x, y, -z + 1/2).
	Fig. 2. View of the hydrogen bonded chains of (I). C—H···S are shown as dashed red lines.

(±)-(rel-3R,3'R)-1,1'-Dimethyl-3,3'-bipyrrolidine-2,2'- dithione top

Crystal data top

C₁₀H₁₆N₂S₂	F(000) = 488
M_r = 228.37	D_x = 1.357 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 419 reflections
a = 20.520 (3) Å	θ = 3.8–30°
b = 5.7237 (7) Å	µ = 0.44 mm⁻¹
c = 11.220 (2) Å	T = 173 K
β = 122.009 (5)°	Cube, colourless
V = 1117.4 (3) Å³	0.45 × 0.42 × 0.16 mm
Z = 4

Data collection top

Bruker APEXII CCD area-detector diffractometer	957 reflections with I > 2σ(I)
ω scans	R_int = 0.016
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	θ_max = 25.5°, θ_min = 2.3°
T_min = 0.827, T_max = 0.933	h = −19→23
1759 measured reflections	k = −6→6
1022 independent reflections	l = −13→5

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.030	w = 1/[σ²(F_o²) + (0.0336P)² + 0.8972P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.077	(Δ/σ)_max < 0.001
S = 1.09	Δρ_max = 0.22 e Å⁻³
1022 reflections	Δρ_min = −0.21 e Å⁻³
65 parameters

Crystal data top

C₁₀H₁₆N₂S₂	V = 1117.4 (3) Å³
M_r = 228.37	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 20.520 (3) Å	µ = 0.44 mm⁻¹
b = 5.7237 (7) Å	T = 173 K
c = 11.220 (2) Å	0.45 × 0.42 × 0.16 mm
β = 122.009 (5)°

Data collection top

Bruker APEXII CCD area-detector diffractometer	1022 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	957 reflections with I > 2σ(I)
T_min = 0.827, T_max = 0.933	R_int = 0.016
1759 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	0 restraints
wR(F²) = 0.077	H-atom parameters constrained
S = 1.09	Δρ_max = 0.22 e Å⁻³
1022 reflections	Δρ_min = −0.21 e Å⁻³
65 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.

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

	x	y	z	U_iso*/U_eq
C1	0.60416 (8)	0.7676 (3)	0.29080 (15)	0.0237 (3)
C2	0.53949 (8)	0.7690 (3)	0.31920 (15)	0.0238 (3)
H2	0.544	0.9137	0.373	0.029*
C3	0.55488 (10)	0.5558 (3)	0.41423 (18)	0.0342 (4)
H3A	0.5591	0.6041	0.5028	0.041*
H3B	0.5127	0.4406	0.366	0.041*
C4	0.63050 (9)	0.4508 (3)	0.44413 (17)	0.0318 (4)
H4A	0.6706	0.4624	0.5453	0.038*
H4B	0.6238	0.2846	0.4155	0.038*
C5	0.72017 (9)	0.5339 (3)	0.36087 (19)	0.0343 (4)
H5A	0.7294	0.6527	0.3086	0.051*
H5B	0.7139	0.3809	0.3168	0.051*
H5C	0.764	0.5289	0.4582	0.051*
N1	0.65091 (7)	0.5918 (2)	0.35941 (13)	0.0254 (3)
S1	0.61374 (2)	0.96194 (8)	0.18993 (4)	0.03401 (17)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0208 (7)	0.0274 (8)	0.0243 (7)	−0.0042 (6)	0.0130 (6)	−0.0032 (6)
C2	0.0227 (8)	0.0261 (8)	0.0265 (7)	0.0000 (6)	0.0157 (6)	0.0012 (6)
C3	0.0330 (9)	0.0395 (10)	0.0391 (9)	0.0072 (7)	0.0252 (8)	0.0136 (7)
C4	0.0318 (9)	0.0333 (9)	0.0366 (9)	0.0046 (7)	0.0225 (7)	0.0090 (7)
C5	0.0244 (9)	0.0406 (10)	0.0429 (10)	0.0030 (7)	0.0213 (7)	−0.0010 (7)
N1	0.0211 (6)	0.0296 (7)	0.0294 (6)	0.0014 (5)	0.0160 (5)	0.0015 (5)
S1	0.0327 (3)	0.0375 (3)	0.0394 (3)	−0.00300 (17)	0.0242 (2)	0.00804 (17)

Geometric parameters (Å, º) top

C1—N1	1.320 (2)	C3—H3B	0.99
C1—C2	1.520 (2)	C4—N1	1.4672 (19)
C1—S1	1.6711 (15)	C4—H4A	0.99
C2—C3	1.539 (2)	C4—H4B	0.99
C2—C2ⁱ	1.539 (3)	C5—N1	1.451 (2)
C2—H2	1	C5—H5A	0.98
C3—C4	1.526 (2)	C5—H5B	0.98
C3—H3A	0.99	C5—H5C	0.98

N1—C1—C2	109.09 (12)	N1—C4—C3	104.31 (12)
N1—C1—S1	126.33 (12)	N1—C4—H4A	110.9
C2—C1—S1	124.58 (11)	C3—C4—H4A	110.9
C1—C2—C3	105.06 (12)	N1—C4—H4B	110.9
C1—C2—C2ⁱ	110.96 (14)	C3—C4—H4B	110.9
C3—C2—C2ⁱ	114.74 (10)	H4A—C4—H4B	108.9
C1—C2—H2	108.6	N1—C5—H5A	109.5
C3—C2—H2	108.6	N1—C5—H5B	109.5
C2ⁱ—C2—H2	108.6	H5A—C5—H5B	109.5
C4—C3—C2	106.00 (13)	N1—C5—H5C	109.5
C4—C3—H3A	110.5	H5A—C5—H5C	109.5
C2—C3—H3A	110.5	H5B—C5—H5C	109.5
C4—C3—H3B	110.5	C1—N1—C5	125.84 (13)
C2—C3—H3B	110.5	C1—N1—C4	115.37 (12)
H3A—C3—H3B	108.7	C5—N1—C4	118.76 (13)

N1—C1—C2—C3	−1.74 (17)	C2—C1—N1—C5	−179.01 (14)
S1—C1—C2—C3	178.97 (11)	S1—C1—N1—C5	0.3 (2)
N1—C1—C2—C2ⁱ	−126.30 (10)	C2—C1—N1—C4	−1.04 (18)
S1—C1—C2—C2ⁱ	54.41 (12)	S1—C1—N1—C4	178.24 (11)
C1—C2—C3—C4	3.64 (17)	C3—C4—N1—C1	3.37 (18)
C2ⁱ—C2—C3—C4	125.78 (16)	C3—C4—N1—C5	−178.51 (14)
C2—C3—C4—N1	−4.13 (17)

Symmetry code: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5B···S1ⁱⁱ	0.98	2.98	3.8373 (18)	146

Symmetry code: (ii) x, y−1, z.

Experimental details

Crystal data
Chemical formula	C₁₀H₁₆N₂S₂
M_r	228.37
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	20.520 (3), 5.7237 (7), 11.220 (2)
β (°)	122.009 (5)
V (Å³)	1117.4 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.44
Crystal size (mm)	0.45 × 0.42 × 0.16

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.827, 0.933
No. of measured, independent and observed [I > 2σ(I)] reflections	1759, 1022, 957
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.077, 1.09
No. of reflections	1022
No. of parameters	65
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.21

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2004), SAINT-Plus and XPREP (Bruker 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5B···S1ⁱ	0.98	2.98	3.8373 (18)	146

Symmetry code: (i) x, y−1, z.

Acknowledgements

This work was supported by the University of the Witwatersrand and the Molecular Sciences Institute, which are thanked for providing the infrastructure required to do this work. Dr R. B. Katz is thanked for performing the preliminary syntheses.

References

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