(1R,2R)-N,N′-Dimethyl­cyclo­hexane-1,2-diamine

Strohmann, C.; Gessner, V.H.; Damme, A.; Koller, S.; Däschlein, C.

doi:10.1107/S1600536808006119

organic compounds

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ISSN: 2056-9890

Volume 64| Part 4| April 2008| Page o687

doi:10.1107/S1600536808006119

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(1R,2R)-N,N′-Dimethylcyclohexane-1,2-diamine

Carsten Strohmann,^a ^* Viktoria H. Gessner,^a Alexander Damme,^a Stephan Koller ^a and Christian Däschlein ^a

^aInstitut für Anorganische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
^*Correspondence e-mail: mail@carsten-strohmann.de

(Received 19 February 2008; accepted 5 March 2008; online 12 March 2008)

The molecule of the title compound, C₈H₁₈N₂, possesses C₂ symmetry. Owing to its stereochemistry, it is used in the synthesis of chiral ligands and metal complexes for asymmetric synthesis. The cyclohexane ring shows a chair conformation with the amino groups in equatorial positions. Contrary to the literature, the title compound is not a liquid, but a crystalline solid at room temperature (293 K). The absolute configuration is assigned from the synthesis.

Related literature

The synthesis of the title compound is described by Kizirian et al. (2005 ). For related literature, see: Larrox and Jacobsen (1994 ); Cole et al. (2005 ); Seebach et al. (1977 ); Strohmann & Gessner (2007 ); Strohmann et al. (2003 , 2004 ); Strohmann, Däschlein & Auer (2006 ); Strohmann, Dilsky & Strohfeldt (2006 ); Strohmmann & Gessner (2007a ,b ).

Experimental

Crystal data

C₈H₁₈N₂
M_r = 142.24
Orthorhombic, P 2₁ 2₁ 2₁
a = 7.552 (4) Å
b = 8.521 (5) Å
c = 14.142 (8) Å
V = 910.0 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 173 (2) K
0.40 × 0.10 × 0.10 mm

Data collection

Bruker APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ) T_min = 0.912, T_max = 0.982
4816 measured reflections
953 independent reflections
784 reflections with I > 2σ(I)
R_int = 0.050

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.111
S = 1.08
953 reflections
101 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.12 e Å⁻³
Δρ_min = −0.12 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯N2ⁱ	0.91 (4)	2.36 (4)	3.250 (4)	166 (3)
Symmetry code: (i) $[-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1999 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808006119/im2055sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808006119/im2055Isup2.hkl

checkCIF report

Comment top

Due to their strong coordination ability diamine bases have become powerful agents in various fields of chemistry e.g. for the deaggregation of organolithium compounds or the coordination of transition metals. Especially chiral amines have attracted special attention in asymmetric synthesis. Thereby, (1R,2R)-N,N'-dimethylcyclohexane-1,2-diamine is an important chiral amine, which serves as a starting material for the synthesis of numerous diamine bases with a cyclohexane framework. The amine crystallizes at room temperature as colourless needles in the orthorhombic crystal system, space group P2₁2₁2₁. The asymmetric unit contains one molecule of the C₂ symmetric amine (see figure 1).

In the unit cell molecules are interconnected via hydrogen bonding to give infinite layers (see figure 2). H atoms (H1N) are arranged in direction to the nitrogen atom (N2) of an adjacent molecule (N1—HN1—N2' angle: 166 (3)°). However, the long N1—N2' distance of 3.250 (4) Å and the short N1—HN1 distance of 0.91 (4) Å indicate weak N–H···N hydrogen bonds.

Related literature top

The synthesis of the title compound is described by Kizirian et al. (2005). For related literature, see: Larrox and Jacobsen (1994); Cole et al. (2005); Seebach et al. (1977); Strohmann & Gessner (2007); Strohmann et al. (2003, 2004); Strohmann, Däschlein & Auer (2006); Strohmann, Dilsky & Strohfeldt (2006); Strohmmann & Gessner (2007a,b).

Experimental top

Treatment of the enantiomerically pure (R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate with two equivalents of ethylchloroformate in the presence of a stochiometric amount of NaOH resulted in the formation of diethyl-(1R,2R)-cyclohexane-1,2-diyldicarbamat. Subsequent reduction with an excess of LiAlH₄ gave colourless crystals of the title compound during bulb-to-bulb destillation. Contrary to a formerly published synthesis, (1R,2R)-N,N'-diemthylcyclohexane-1,2-diamine is not liquid but a highly hygroscopic crystalline solid.

¹H-NMR (500.1 MHz, CDCl₃): 0.86–0.94 (m, 2H; CH₂CHN), 1.13–1.19 (m, 2H; CH₂CH₂CHN), 1.61–1.67 (m, 2H; CH₂CH₂CHN), 1.68–1.75 (br, 2H, NH), 1.93–2.00 (m, 2H; CH₂CHN), 2.02–2.06 (m, 2H; CHNCHN), 2.33 (s, 6H; NCH₃).

¹³C-NMR (100.6 MHz, CDCl₃): 25.0 (CH₂CH₂CHN), 30.8 (CH₂CHN), 33.7 (CH₃), 63.2 (CHN).

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: SHELXS90 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP plot of the molecular structure of (1R,2R)-N,N'-diemthylcyclohexane-1,2-diamine. Thermal ellipsoids are drawn at the 50% probability level.
	Fig. 2. ORTEP plot of the unit cell.
	Fig. 3. Display of the hydrogen bonding.

(1R,2R)-N,N'-Dimethylcyclohexane-1,2-diamine top

Crystal data top

C₈H₁₈N₂	F(000) = 320
M_r = 142.24	D_x = 1.038 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Melting point: 313 K
Hall symbol: P 2ac 2ab	Mo Kα radiation, λ = 0.71073 Å
a = 7.552 (4) Å	θ = 2.8–25.0°
b = 8.521 (5) Å	µ = 0.06 mm⁻¹
c = 14.142 (8) Å	T = 173 K
V = 910.0 (8) Å³	Needle, colourless
Z = 4	0.40 × 0.10 × 0.10 mm

Data collection top

Bruker APEXCCD diffractometer	953 independent reflections
Radiation source: fine-focus sealed tube	784 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.050
ω scans	θ_max = 25.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −8→8
T_min = 0.912, T_max = 0.982	k = −10→9
4816 measured reflections	l = −16→16

Refinement top

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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ²(F_o²) + (0.0405P)² + 0.258P] where P = (F_o² + 2F_c²)/3
953 reflections	(Δ/σ)_max < 0.001
101 parameters	Δρ_max = 0.12 e Å⁻³
0 restraints	Δρ_min = −0.12 e Å⁻³

Crystal data top

C₈H₁₈N₂	V = 910.0 (8) Å³
M_r = 142.24	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 7.552 (4) Å	µ = 0.06 mm⁻¹
b = 8.521 (5) Å	T = 173 K
c = 14.142 (8) Å	0.40 × 0.10 × 0.10 mm

Data collection top

Bruker APEXCCD diffractometer	953 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1999)	784 reflections with I > 2σ(I)
T_min = 0.912, T_max = 0.982	R_int = 0.050
4816 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	0 restraints
wR(F²) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	Δρ_max = 0.12 e Å⁻³
953 reflections	Δρ_min = −0.12 e Å⁻³
101 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

	x	y	z	U_iso*/U_eq
C1	0.8581 (4)	0.3857 (3)	0.28989 (19)	0.0346 (7)
H1	0.8702	0.5000	0.3046	0.042*
C2	0.6814 (4)	0.3316 (4)	0.3294 (2)	0.0477 (9)
H2A	0.6785	0.3525	0.3982	0.057*
H2B	0.6703	0.2168	0.3202	0.057*
C3	0.5242 (4)	0.4129 (5)	0.2827 (3)	0.0608 (11)
H3A	0.4128	0.3663	0.3067	0.073*
H3B	0.5247	0.5256	0.2999	0.073*
C4	0.5304 (4)	0.3970 (4)	0.1764 (3)	0.0528 (10)
H4A	0.5131	0.2857	0.1586	0.063*
H4B	0.4333	0.4590	0.1479	0.063*
C5	0.7059 (4)	0.4540 (4)	0.1385 (2)	0.0458 (9)
H5A	0.7174	0.5679	0.1509	0.055*
H5B	0.7091	0.4381	0.0691	0.055*
C6	0.8605 (4)	0.3685 (3)	0.18321 (18)	0.0331 (7)
H6	0.8514	0.2545	0.1671	0.040*
C7	1.0546 (5)	0.3573 (4)	0.4252 (2)	0.0581 (10)
H7A	1.0807	0.4699	0.4250	0.087*
H7B	1.1583	0.2994	0.4480	0.087*
H7C	0.9537	0.3367	0.4670	0.087*
C8	1.0664 (5)	0.3767 (5)	0.0508 (2)	0.0644 (11)
H8A	1.0492	0.2629	0.0465	0.097*
H8B	1.1894	0.4025	0.0350	0.097*
H8C	0.9866	0.4296	0.0065	0.097*
N1	1.0117 (3)	0.3064 (4)	0.32977 (18)	0.0389 (7)
H1N	0.985 (4)	0.203 (4)	0.329 (2)	0.056 (10)*
N2	1.0282 (4)	0.4287 (3)	0.14644 (19)	0.0413 (7)
H2N	1.109 (4)	0.391 (4)	0.193 (2)	0.045 (9)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0385 (17)	0.0216 (15)	0.0438 (17)	0.0043 (16)	0.0006 (14)	0.0013 (13)
C2	0.044 (2)	0.0420 (19)	0.057 (2)	0.0050 (17)	0.0110 (17)	0.0051 (17)
C3	0.039 (2)	0.053 (2)	0.090 (3)	0.0029 (19)	0.010 (2)	0.007 (2)
C4	0.0335 (19)	0.0403 (19)	0.085 (3)	−0.0023 (17)	−0.0126 (19)	0.0081 (19)
C5	0.046 (2)	0.0355 (19)	0.056 (2)	−0.0032 (17)	−0.0131 (16)	0.0054 (16)
C6	0.0341 (16)	0.0251 (16)	0.0400 (17)	−0.0025 (15)	−0.0054 (14)	−0.0008 (13)
C7	0.068 (2)	0.055 (2)	0.052 (2)	0.010 (2)	−0.0109 (18)	−0.0046 (18)
C8	0.057 (2)	0.085 (3)	0.052 (2)	−0.008 (2)	0.0120 (18)	0.005 (2)
N1	0.0389 (15)	0.0388 (16)	0.0390 (15)	0.0029 (14)	−0.0033 (13)	0.0002 (13)
N2	0.0370 (16)	0.0514 (18)	0.0355 (15)	−0.0048 (14)	0.0004 (13)	0.0048 (13)

Geometric parameters (Å, º) top

C1—N1	1.455 (4)	C5—H5A	0.9900
C1—C6	1.516 (4)	C5—H5B	0.9900
C1—C2	1.519 (4)	C6—N2	1.462 (4)
C1—H1	1.0000	C6—H6	1.0000
C2—C3	1.525 (4)	C7—N1	1.454 (4)
C2—H2A	0.9900	C7—H7A	0.9800
C2—H2B	0.9900	C7—H7B	0.9800
C3—C4	1.511 (5)	C7—H7C	0.9800
C3—H3A	0.9900	C8—N2	1.452 (4)
C3—H3B	0.9900	C8—H8A	0.9800
C4—C5	1.510 (4)	C8—H8B	0.9800
C4—H4A	0.9900	C8—H8C	0.9800
C4—H4B	0.9900	N1—H1N	0.91 (4)
C5—C6	1.515 (4)	N2—H2N	0.96 (3)

N1—C1—C6	109.4 (2)	C4—C5—H5B	109.2
N1—C1—C2	114.6 (2)	C6—C5—H5B	109.2
C6—C1—C2	110.3 (3)	H5A—C5—H5B	107.9
N1—C1—H1	107.4	N2—C6—C5	110.5 (2)
C6—C1—H1	107.4	N2—C6—C1	109.3 (2)
C2—C1—H1	107.4	C5—C6—C1	111.1 (3)
C1—C2—C3	112.8 (3)	N2—C6—H6	108.6
C1—C2—H2A	109.0	C5—C6—H6	108.6
C3—C2—H2A	109.0	C1—C6—H6	108.6
C1—C2—H2B	109.0	N1—C7—H7A	109.5
C3—C2—H2B	109.0	N1—C7—H7B	109.5
H2A—C2—H2B	107.8	H7A—C7—H7B	109.5
C4—C3—C2	111.4 (3)	N1—C7—H7C	109.5
C4—C3—H3A	109.3	H7A—C7—H7C	109.5
C2—C3—H3A	109.3	H7B—C7—H7C	109.5
C4—C3—H3B	109.3	N2—C8—H8A	109.5
C2—C3—H3B	109.3	N2—C8—H8B	109.5
H3A—C3—H3B	108.0	H8A—C8—H8B	109.5
C5—C4—C3	110.6 (3)	N2—C8—H8C	109.5
C5—C4—H4A	109.5	H8A—C8—H8C	109.5
C3—C4—H4A	109.5	H8B—C8—H8C	109.5
C5—C4—H4B	109.5	C7—N1—C1	113.5 (2)
C3—C4—H4B	109.5	C7—N1—H1N	111 (2)
H4A—C4—H4B	108.1	C1—N1—H1N	106 (2)
C4—C5—C6	111.9 (3)	C8—N2—C6	113.4 (3)
C4—C5—H5A	109.2	C8—N2—H2N	114.6 (19)
C6—C5—H5A	109.2	C6—N2—H2N	100.9 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···N2ⁱ	0.91 (4)	2.36 (4)	3.250 (4)	166 (3)

Symmetry code: (i) −x+2, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₈H₁₈N₂
M_r	142.24
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	173
a, b, c (Å)	7.552 (4), 8.521 (5), 14.142 (8)
V (Å³)	910.0 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.06
Crystal size (mm)	0.40 × 0.10 × 0.10

Data collection
Diffractometer	Bruker APEXCCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1999)
T_min, T_max	0.912, 0.982
No. of measured, independent and observed [I > 2σ(I)] reflections	4816, 953, 784
R_int	0.050
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.111, 1.08
No. of reflections	953
No. of parameters	101
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.12, −0.12

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 1999), SHELXS90 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···N2ⁱ	0.91 (4)	2.36 (4)	3.250 (4)	166 (3)

Symmetry code: (i) −x+2, y−1/2, −z+1/2.

Acknowledgements

We are grateful to the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie (FCI). VHG thanks the FCI, and CD the Studienstiftung des deutschen Volkes for a doctoral scholarship.

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