organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

Cyclo­hexane-1,3-diyl bis­­(N-phenyl­carbamate)

aSchool of Industrial Technology, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: hkfun@usm.my

(Received 18 August 2010; accepted 21 August 2010; online 28 August 2010)

The asymmetric unit of the title compound, C20H22N2O4, comprises two crystallographically independent mol­ecules (A and B) with slightly different geometries. The dihedral angle between the two terminal phenyl rings is 61.7 (1)° in mol­ecule A and 29.6 (1)° in B. The cyclo­hexane rings adopt chair conformations. In the crystal packing, inter­molecular N—H⋯O hydrogen bonds inter­connect adjacent mol­ecules into a ladder-like structure along the c axis incorporating R22(20) ring motifs. The crystal packing is further stabilized by weak inter­molecular C—H⋯π inter­actions.

Related literature

For general background and the synthesis of carbamates, see: Banerjee et al. (1978[Banerjee, S., Dutta, S. & Chakraborti, S. K. (1978). J. Indian Chem. Soc. 55, 284-286.]); Ghalib et al. (2010[Ghalib, R. M., Sulaiman, O., Mehdi, S. H., Goh, J. H. & Fun, H.-K. (2010). Acta Cryst. E66, o1889-o1890.]); Graia et al. (2009[Graia, M., Raza Murad, G., Krimi Ammar, M., Mehdi, S. H. & Hashim, R. (2009). Acta Cryst. E65, o3231.]); Ibuka et al. (1985[Ibuka, T., Chu, G. N., Aoyagi, T., Kitada, K., Tsukida, T. & Yoneda, F. (1985). Chem. Pharm. Bull. 33, 451-453.]); Lapidus et al. (1987[Lapidus, A. L., Pirozhkov, S. D., Kapkin, V. D. & Krylova, A. Y. (1987). Org. Tech. 13, 160.]); Loev & Kormendy (1963[Loev, B. & Kormendy, M. F. (1963). J. Org. Chem. 28, 3421-3426.]); Niu et al. (2007[Niu, D. F., Zhang, L., Xiao, L. P., Luo, Y. W. & Lu, J. X. (2007). Appl. Organomet. Chem. 21, 941-944.]). For ring conformation and puckering analysis, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]). For graph-set motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For a related structure, see: Ghalib et al. (2010[Ghalib, R. M., Sulaiman, O., Mehdi, S. H., Goh, J. H. & Fun, H.-K. (2010). Acta Cryst. E66, o1889-o1890.]). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]).

[Scheme 1]

Experimental

Crystal data
  • C20H22N2O4

  • Mr = 354.40

  • Monoclinic, P 21 /c

  • a = 38.356 (7) Å

  • b = 9.5453 (16) Å

  • c = 9.8472 (16) Å

  • β = 91.034 (3)°

  • V = 3604.7 (10) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 100 K

  • 0.55 × 0.15 × 0.13 mm

Data collection
  • Bruker APEXII DUO CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.951, Tmax = 0.988

  • 30037 measured reflections

  • 10472 independent reflections

  • 6630 reflections with I > 2σ(I)

  • Rint = 0.057

Refinement
  • R[F2 > 2σ(F2)] = 0.064

  • wR(F2) = 0.180

  • S = 1.08

  • 10472 reflections

  • 485 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.33 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of C15A–C20A and C1B–C6B phenyl rings, respectively.

D—H⋯A D—H H⋯A DA D—H⋯A
N1A—H1NA⋯O1Ai 0.83 (2) 2.13 (2) 2.953 (2) 174 (2)
N2A—H2NA⋯O4Ai 0.91 (3) 2.09 (3) 2.934 (2) 154 (2)
N1B—H1NB⋯O1Bii 0.93 (3) 2.10 (3) 2.920 (2) 147 (2)
N2B—H2NB⋯O4Bii 0.88 (3) 2.02 (3) 2.874 (2) 163 (3)
C13A—H13BCg1iii 0.97 2.86 3.734 (2) 151
C13B—H13CCg2iv 0.97 2.86 3.732 (2) 150
Symmetry codes: (i) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]; (iii) -x+1, -y, -z+1; (iv) -x, -y+2, -z.

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

Carbamates are a well-known class of organic compounds. They can be prepared by nickel-catalyzed coupling of CO2 and amines (Niu et al., 2007), by stirring of alcohols including steroids as well as primary and secondary alcohols, polyols, phenols with sodium cyanate and trifluoroacetic acid (Loev & Kormendy, 1963), by carbonylation of aromatic nitro compounds (Lapidus et al., 1987), by the reaction of isocyanates with alcohols in presence of Lewis acid (Ibuka et al., 1985) and by the reaction of an amine and an alcohol with phosgene. Phytosterol, β-sitosterol, stigmasterol, cholesterol, cyclohexanol and α-terpineol react with phenyl isocyanate to give carbamates (Banerjee et al., 1978; Graia et al., 2009; Ghalib et al., 2010). In the present work, the title compound has been synthesized by the reaction of cyclohexane-1,3-diol with phenylisocyanate in the presence of catalytic amount of HCl in chloroform solvent.

The asymmetric unit of the title compound comprises of two crystallographically independent molecules, designated A and B (Fig. 1). The orientation of the C1–C6 phenyl ring with respect to the rest of the molecule is different in A and B, as shown in the superposition of the non-H atoms of molecules A and B (Fig. 2) using XP in SHELXTL (Sheldrick, 2008); the r.m.s. deviation is 0.474 Å.

In each molecule, the cyclohexane ring (C8-C13) adopts a chair conformation; the puckering parameters are Q = 0.566 (2) Å, θ = 176.6 (2)°, φ = 328 (4)° for molecule A and Q = 0.566 (2) Å, θ = 176.2 (2)°, φ = 283 (4)° for molecule B. The dihedral angle between the C1–C6 and C15–C20 phenyl rings is 61.7 (1)° in molecule A and 29.6 (1)° in B. The geometric parameters are consistent with a related structure (Ghalib et al., 2010).

In the crystal packing, intermolecular N1A—H1NA···O1A, N2A—H2NA···O4A, N1B—H1NB···O1B, N2B—H2NB···O4B hydrogen bonds (Table 1) link adjacent molecules into one-dimensional chains incorporating R22(20) ring motifs (Bernstein et al., 1995) along the c axis (Fig. 3). Further stabilization of the crystal packing is provided by weak intermolecular C13A—H13B···Cg1 and C13B—H13C···Cg2 interactions (Table 1) where Cg1 and Cg2 are the centroids of C15A-C20A and C1B-C6B phenyl rings, respectively.

Related literature top

For general background and the synthesis of carbamates, see: Banerjee et al. (1978); Ghalib et al. (2010); Graia et al. (2009); Ibuka et al. (1985); Lapidus et al. (1987); Loev & Kormendy (1963); Niu et al. (2007). For ring conformation and puckering analysis, see: Cremer & Pople (1975). For graph-set motifs, see: Bernstein et al. (1995). For a related structure, see: Ghalib et al. (2010). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Experimental top

A mixture of cyclohexane-1,3-diol (1.005 ml) and phenyl isocyanate (2.174 ml) in a 1:2 molar ratio was stirred in chloroform for 30 minutes in the presence of catalytic amount of HCl. The reaction mixture was dried with rota vapor at low pressure and then crystallized in a 1:1 mixture of chloroform and alcohol to afford colourless needle-like single crystals (yield: 2.60 g, m.p. 489.2 K). The melting point was taken using a Thermo Fisher digital melting point apparatus of IA9000 series and is uncorrected

Refinement top

N-bound H atoms were located in a difference Fourier map and allowed refined freely [range of N—H = 0.83 (2)–0.92 (3) Å]. The remaining H atoms were placed in their calculated positions, with C–H = 0.93–0.98 Å, and refined using a riding model, with Uiso(H) = 1.2Ueq(C).

Structure description top

Carbamates are a well-known class of organic compounds. They can be prepared by nickel-catalyzed coupling of CO2 and amines (Niu et al., 2007), by stirring of alcohols including steroids as well as primary and secondary alcohols, polyols, phenols with sodium cyanate and trifluoroacetic acid (Loev & Kormendy, 1963), by carbonylation of aromatic nitro compounds (Lapidus et al., 1987), by the reaction of isocyanates with alcohols in presence of Lewis acid (Ibuka et al., 1985) and by the reaction of an amine and an alcohol with phosgene. Phytosterol, β-sitosterol, stigmasterol, cholesterol, cyclohexanol and α-terpineol react with phenyl isocyanate to give carbamates (Banerjee et al., 1978; Graia et al., 2009; Ghalib et al., 2010). In the present work, the title compound has been synthesized by the reaction of cyclohexane-1,3-diol with phenylisocyanate in the presence of catalytic amount of HCl in chloroform solvent.

The asymmetric unit of the title compound comprises of two crystallographically independent molecules, designated A and B (Fig. 1). The orientation of the C1–C6 phenyl ring with respect to the rest of the molecule is different in A and B, as shown in the superposition of the non-H atoms of molecules A and B (Fig. 2) using XP in SHELXTL (Sheldrick, 2008); the r.m.s. deviation is 0.474 Å.

In each molecule, the cyclohexane ring (C8-C13) adopts a chair conformation; the puckering parameters are Q = 0.566 (2) Å, θ = 176.6 (2)°, φ = 328 (4)° for molecule A and Q = 0.566 (2) Å, θ = 176.2 (2)°, φ = 283 (4)° for molecule B. The dihedral angle between the C1–C6 and C15–C20 phenyl rings is 61.7 (1)° in molecule A and 29.6 (1)° in B. The geometric parameters are consistent with a related structure (Ghalib et al., 2010).

In the crystal packing, intermolecular N1A—H1NA···O1A, N2A—H2NA···O4A, N1B—H1NB···O1B, N2B—H2NB···O4B hydrogen bonds (Table 1) link adjacent molecules into one-dimensional chains incorporating R22(20) ring motifs (Bernstein et al., 1995) along the c axis (Fig. 3). Further stabilization of the crystal packing is provided by weak intermolecular C13A—H13B···Cg1 and C13B—H13C···Cg2 interactions (Table 1) where Cg1 and Cg2 are the centroids of C15A-C20A and C1B-C6B phenyl rings, respectively.

For general background and the synthesis of carbamates, see: Banerjee et al. (1978); Ghalib et al. (2010); Graia et al. (2009); Ibuka et al. (1985); Lapidus et al. (1987); Loev & Kormendy (1963); Niu et al. (2007). For ring conformation and puckering analysis, see: Cremer & Pople (1975). For graph-set motifs, see: Bernstein et al. (1995). For a related structure, see: Ghalib et al. (2010). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of the title compound, showing 50% probability displacement ellipsoids for non-H atoms and the atom-numbering scheme.
[Figure 2] Fig. 2. Fit of molecule A (dashed lines) on molecule B (solid lines). H atoms have been omitted for clarity.
[Figure 3] Fig. 3. The crystal structure of the title compound, viewed along the b axis, showing molecular chains along the c axis. H atoms not involved in hydrogen bonds (dashed lines) have been omitted for clarity.
Cyclohexane-1,3-diyl bis(N-phenylcarbamate) top
Crystal data top
C20H22N2O4F(000) = 1504
Mr = 354.40Dx = 1.306 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3229 reflections
a = 38.356 (7) Åθ = 3.0–32.1°
b = 9.5453 (16) ŵ = 0.09 mm1
c = 9.8472 (16) ÅT = 100 K
β = 91.034 (3)°Needle, colourless
V = 3604.7 (10) Å30.55 × 0.15 × 0.13 mm
Z = 8
Data collection top
Bruker APEXII DUO CCD area-detector
diffractometer
10472 independent reflections
Radiation source: fine-focus sealed tube6630 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.057
φ and ω scansθmax = 30.0°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 5153
Tmin = 0.951, Tmax = 0.988k = 1113
30037 measured reflectionsl = 1313
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.064Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.180H atoms treated by a mixture of independent and constrained refinement
S = 1.08 w = 1/[σ2(Fo2) + (0.0587P)2 + 2.1169P]
where P = (Fo2 + 2Fc2)/3
10472 reflections(Δ/σ)max = 0.001
485 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = 0.25 e Å3
Crystal data top
C20H22N2O4V = 3604.7 (10) Å3
Mr = 354.40Z = 8
Monoclinic, P21/cMo Kα radiation
a = 38.356 (7) ŵ = 0.09 mm1
b = 9.5453 (16) ÅT = 100 K
c = 9.8472 (16) Å0.55 × 0.15 × 0.13 mm
β = 91.034 (3)°
Data collection top
Bruker APEXII DUO CCD area-detector
diffractometer
10472 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
6630 reflections with I > 2σ(I)
Tmin = 0.951, Tmax = 0.988Rint = 0.057
30037 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0640 restraints
wR(F2) = 0.180H atoms treated by a mixture of independent and constrained refinement
S = 1.08Δρmax = 0.33 e Å3
10472 reflectionsΔρmin = 0.25 e Å3
485 parameters
Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.

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.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O1A0.32324 (4)0.22226 (16)0.31570 (14)0.0210 (3)
O2A0.35690 (3)0.27958 (16)0.49976 (14)0.0213 (3)
O3A0.47863 (3)0.24586 (16)0.53335 (14)0.0218 (3)
O4A0.51876 (4)0.22687 (17)0.36729 (14)0.0259 (3)
N1A0.30419 (4)0.19662 (19)0.53465 (18)0.0198 (4)
N2A0.53147 (4)0.17410 (19)0.59053 (17)0.0194 (4)
C1A0.25950 (5)0.0743 (2)0.3965 (2)0.0215 (4)
H1AA0.27600.04750.33350.026*
C2A0.22478 (6)0.0356 (2)0.3788 (2)0.0265 (5)
H2AA0.21800.01660.30310.032*
C3A0.20014 (6)0.0740 (3)0.4726 (2)0.0290 (5)
H3AA0.17690.04860.45940.035*
C4A0.21015 (6)0.1504 (3)0.5862 (2)0.0296 (5)
H4AA0.19370.17470.65010.036*
C5A0.24475 (5)0.1909 (2)0.6053 (2)0.0235 (4)
H5AA0.25140.24260.68160.028*
C6A0.26940 (5)0.1536 (2)0.5095 (2)0.0194 (4)
C7A0.32746 (5)0.2314 (2)0.4382 (2)0.0165 (4)
C8A0.38682 (5)0.3068 (2)0.4156 (2)0.0180 (4)
H8AA0.38480.25310.33100.022*
C9A0.38944 (5)0.4620 (2)0.3841 (2)0.0213 (4)
H9AA0.38750.51550.46730.026*
H9AB0.37040.48910.32350.026*
C10A0.42429 (5)0.4948 (2)0.3174 (2)0.0213 (4)
H10A0.42520.44810.23000.026*
H10B0.42600.59490.30170.026*
C11A0.45518 (5)0.4471 (2)0.4063 (2)0.0210 (4)
H11A0.47680.46620.36030.025*
H11B0.45540.49870.49120.025*
C12A0.45230 (5)0.2912 (2)0.4349 (2)0.0176 (4)
H12A0.45480.23830.35030.021*
C13A0.41781 (5)0.2548 (2)0.4998 (2)0.0172 (4)
H13A0.41710.29630.58970.021*
H13B0.41620.15390.51010.021*
C14A0.51069 (5)0.2170 (2)0.4859 (2)0.0180 (4)
C15A0.56754 (5)0.1433 (2)0.5863 (2)0.0179 (4)
C16A0.58223 (5)0.0713 (2)0.6959 (2)0.0206 (4)
H16A0.56810.04040.76560.025*
C17A0.61787 (6)0.0451 (2)0.7023 (2)0.0255 (5)
H17A0.62750.00200.77670.031*
C18A0.63918 (5)0.0888 (2)0.5979 (2)0.0259 (5)
H18A0.66310.07210.60220.031*
C19A0.62432 (5)0.1581 (2)0.4871 (2)0.0240 (5)
H19A0.63840.18580.41590.029*
C20A0.58872 (5)0.1867 (2)0.4809 (2)0.0195 (4)
H20A0.57910.23450.40690.023*
O1B0.02136 (4)0.77244 (17)0.13203 (14)0.0242 (3)
O2B0.01910 (3)0.75338 (16)0.03230 (14)0.0207 (3)
O3B0.14054 (3)0.71216 (15)0.00059 (14)0.0189 (3)
O4B0.17604 (4)0.74059 (17)0.18627 (14)0.0242 (3)
N1B0.03341 (4)0.82633 (18)0.09211 (17)0.0179 (3)
N2B0.19386 (4)0.78876 (19)0.03047 (18)0.0184 (4)
C1B0.09132 (5)0.8200 (2)0.0143 (2)0.0191 (4)
H1BA0.08250.77050.08880.023*
C2B0.12654 (5)0.8537 (2)0.0058 (2)0.0232 (4)
H2BA0.14120.82700.07540.028*
C3B0.14022 (5)0.9265 (2)0.1049 (2)0.0243 (5)
H3BA0.16390.94800.10990.029*
C4B0.11823 (5)0.9667 (2)0.2078 (2)0.0233 (4)
H4BA0.12721.01570.28220.028*
C5B0.08294 (5)0.9346 (2)0.2011 (2)0.0195 (4)
H5BA0.06840.96220.27070.023*
C6B0.06928 (5)0.8607 (2)0.08937 (19)0.0157 (4)
C7B0.01295 (5)0.7830 (2)0.0140 (2)0.0172 (4)
C8B0.04525 (5)0.7077 (2)0.06741 (19)0.0165 (4)
H8BA0.04290.76170.15140.020*
C9B0.04178 (5)0.5521 (2)0.0974 (2)0.0184 (4)
H9BA0.04120.49980.01290.022*
H9BB0.02020.53480.14410.022*
C10B0.07256 (5)0.5031 (2)0.1857 (2)0.0192 (4)
H10C0.07030.40340.20290.023*
H10D0.07210.55120.27240.023*
C11B0.10739 (5)0.5314 (2)0.1179 (2)0.0194 (4)
H11C0.12640.50280.17800.023*
H11D0.10880.47740.03480.023*
C12B0.11062 (5)0.6861 (2)0.08605 (19)0.0160 (4)
H12B0.11300.73980.17060.019*
C13B0.07986 (5)0.7408 (2)0.0023 (2)0.0168 (4)
H13C0.08210.84150.00800.020*
H13D0.08030.69920.08750.020*
C14B0.17103 (5)0.7465 (2)0.0642 (2)0.0162 (4)
C15B0.22895 (5)0.8287 (2)0.00429 (19)0.0178 (4)
C16B0.24314 (6)0.9297 (2)0.0886 (2)0.0247 (5)
H16B0.22940.97150.15600.030*
C17B0.27798 (6)0.9682 (3)0.0719 (3)0.0342 (6)
H17B0.28771.03380.12990.041*
C18B0.29811 (6)0.9090 (3)0.0306 (3)0.0374 (6)
H18B0.32120.93620.04280.045*
C19B0.28398 (6)0.8100 (3)0.1147 (3)0.0337 (6)
H19B0.29760.77080.18390.040*
C20B0.24941 (5)0.7677 (2)0.0972 (2)0.0251 (5)
H20B0.24010.69920.15320.030*
H1NA0.3111 (6)0.219 (2)0.612 (2)0.014 (6)*
H2NA0.5227 (7)0.181 (3)0.676 (3)0.048 (8)*
H1NB0.0234 (7)0.824 (3)0.177 (3)0.038 (7)*
H2NB0.1855 (6)0.795 (3)0.114 (3)0.031 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O1A0.0194 (7)0.0295 (8)0.0140 (7)0.0001 (6)0.0018 (5)0.0010 (6)
O2A0.0154 (6)0.0328 (8)0.0156 (7)0.0043 (6)0.0008 (5)0.0037 (6)
O3A0.0153 (6)0.0357 (9)0.0142 (7)0.0044 (6)0.0003 (5)0.0007 (6)
O4A0.0215 (7)0.0415 (9)0.0147 (7)0.0057 (7)0.0007 (6)0.0019 (7)
N1A0.0174 (8)0.0301 (10)0.0118 (8)0.0032 (7)0.0010 (6)0.0028 (7)
N2A0.0176 (8)0.0271 (9)0.0136 (8)0.0022 (7)0.0005 (6)0.0017 (7)
C1A0.0207 (9)0.0231 (10)0.0206 (10)0.0015 (8)0.0035 (8)0.0004 (8)
C2A0.0260 (11)0.0282 (12)0.0251 (11)0.0075 (9)0.0090 (9)0.0016 (9)
C3A0.0187 (10)0.0334 (13)0.0346 (13)0.0067 (9)0.0050 (9)0.0081 (10)
C4A0.0204 (10)0.0326 (12)0.0361 (13)0.0001 (9)0.0058 (9)0.0038 (10)
C5A0.0204 (10)0.0276 (11)0.0225 (11)0.0009 (8)0.0020 (8)0.0022 (9)
C6A0.0166 (9)0.0199 (10)0.0214 (10)0.0024 (7)0.0017 (8)0.0027 (8)
C7A0.0155 (9)0.0179 (9)0.0161 (10)0.0012 (7)0.0032 (7)0.0013 (7)
C8A0.0158 (8)0.0230 (10)0.0154 (9)0.0015 (7)0.0021 (7)0.0004 (8)
C9A0.0209 (9)0.0215 (10)0.0215 (10)0.0025 (8)0.0017 (8)0.0009 (8)
C10A0.0281 (10)0.0168 (10)0.0190 (10)0.0029 (8)0.0010 (8)0.0000 (8)
C11A0.0204 (9)0.0241 (11)0.0185 (10)0.0056 (8)0.0028 (8)0.0012 (8)
C12A0.0157 (9)0.0240 (10)0.0131 (9)0.0014 (7)0.0025 (7)0.0007 (8)
C13A0.0169 (9)0.0204 (10)0.0143 (9)0.0000 (7)0.0014 (7)0.0019 (7)
C14A0.0157 (9)0.0222 (10)0.0161 (9)0.0010 (7)0.0006 (7)0.0013 (8)
C15A0.0186 (9)0.0178 (9)0.0173 (10)0.0013 (7)0.0015 (7)0.0030 (8)
C16A0.0244 (10)0.0201 (10)0.0172 (10)0.0033 (8)0.0023 (8)0.0026 (8)
C17A0.0276 (11)0.0243 (11)0.0243 (11)0.0062 (9)0.0076 (9)0.0041 (9)
C18A0.0184 (10)0.0280 (12)0.0310 (12)0.0037 (8)0.0049 (9)0.0061 (10)
C19A0.0210 (10)0.0222 (11)0.0288 (12)0.0001 (8)0.0021 (8)0.0021 (9)
C20A0.0205 (9)0.0199 (10)0.0181 (10)0.0015 (8)0.0001 (8)0.0010 (8)
O1B0.0218 (7)0.0381 (9)0.0128 (7)0.0066 (6)0.0001 (6)0.0021 (6)
O2B0.0144 (6)0.0333 (8)0.0145 (7)0.0035 (6)0.0014 (5)0.0018 (6)
O3B0.0142 (6)0.0283 (8)0.0142 (7)0.0040 (6)0.0004 (5)0.0019 (6)
O4B0.0204 (7)0.0407 (9)0.0115 (7)0.0029 (6)0.0017 (5)0.0021 (6)
N1B0.0164 (8)0.0256 (9)0.0116 (8)0.0022 (7)0.0000 (6)0.0010 (7)
N2B0.0148 (7)0.0281 (9)0.0123 (8)0.0021 (7)0.0012 (6)0.0010 (7)
C1B0.0202 (9)0.0201 (10)0.0170 (10)0.0005 (8)0.0010 (8)0.0016 (8)
C2B0.0197 (9)0.0252 (11)0.0249 (11)0.0004 (8)0.0025 (8)0.0029 (9)
C3B0.0178 (9)0.0238 (11)0.0312 (12)0.0037 (8)0.0046 (8)0.0030 (9)
C4B0.0252 (10)0.0210 (10)0.0233 (11)0.0038 (8)0.0083 (8)0.0021 (8)
C5B0.0244 (10)0.0196 (10)0.0145 (9)0.0019 (8)0.0023 (8)0.0003 (8)
C6B0.0158 (8)0.0174 (9)0.0139 (9)0.0009 (7)0.0028 (7)0.0034 (7)
C7B0.0174 (9)0.0195 (10)0.0146 (9)0.0001 (7)0.0002 (7)0.0018 (8)
C8B0.0151 (8)0.0223 (10)0.0121 (9)0.0012 (7)0.0020 (7)0.0001 (7)
C9B0.0174 (9)0.0223 (10)0.0154 (9)0.0038 (7)0.0008 (7)0.0009 (8)
C10B0.0222 (9)0.0184 (10)0.0169 (10)0.0032 (8)0.0003 (8)0.0015 (8)
C11B0.0197 (9)0.0204 (10)0.0179 (10)0.0027 (8)0.0010 (7)0.0017 (8)
C12B0.0136 (8)0.0210 (10)0.0134 (9)0.0011 (7)0.0007 (7)0.0002 (7)
C13B0.0162 (9)0.0183 (10)0.0159 (10)0.0013 (7)0.0022 (7)0.0019 (7)
C14B0.0145 (8)0.0202 (10)0.0138 (9)0.0001 (7)0.0002 (7)0.0001 (7)
C15B0.0163 (9)0.0235 (10)0.0137 (9)0.0022 (8)0.0014 (7)0.0048 (8)
C16B0.0256 (10)0.0243 (11)0.0242 (11)0.0037 (9)0.0001 (8)0.0014 (9)
C17B0.0333 (12)0.0316 (13)0.0379 (14)0.0133 (10)0.0046 (11)0.0009 (11)
C18B0.0209 (11)0.0450 (15)0.0462 (16)0.0111 (10)0.0010 (10)0.0063 (13)
C19B0.0217 (11)0.0485 (16)0.0306 (13)0.0002 (10)0.0066 (9)0.0002 (11)
C20B0.0181 (9)0.0359 (12)0.0212 (11)0.0019 (9)0.0020 (8)0.0044 (9)
Geometric parameters (Å, º) top
O1A—C7A1.218 (2)O1B—C7B1.216 (2)
O2A—C7A1.352 (2)O2B—C7B1.349 (2)
O2A—C8A1.451 (2)O2B—C8B1.457 (2)
O3A—C14A1.352 (2)O3B—C14B1.357 (2)
O3A—C12A1.453 (2)O3B—C12B1.457 (2)
O4A—C14A1.218 (2)O4B—C14B1.215 (2)
N1A—C7A1.356 (2)N1B—C7B1.360 (3)
N1A—C6A1.414 (3)N1B—C6B1.415 (2)
N1A—H1NA0.83 (2)N1B—H1NB0.92 (3)
N2A—C14A1.354 (3)N2B—C14B1.352 (2)
N2A—C15A1.416 (2)N2B—C15B1.418 (2)
N2A—H2NA0.92 (3)N2B—H2NB0.88 (3)
C1A—C2A1.390 (3)C1B—C2B1.390 (3)
C1A—C6A1.392 (3)C1B—C6B1.393 (2)
C1A—H1AA0.93C1B—H1BA0.93
C2A—C3A1.383 (3)C2B—C3B1.387 (3)
C2A—H2AA0.93C2B—H2BA0.93
C3A—C4A1.383 (3)C3B—C4B1.384 (3)
C3A—H3AA0.93C3B—H3BA0.93
C4A—C5A1.392 (3)C4B—C5B1.388 (3)
C4A—H4AA0.93C4B—H4BA0.93
C5A—C6A1.394 (3)C5B—C6B1.400 (3)
C5A—H5AA0.93C5B—H5BA0.93
C8A—C9A1.517 (3)C8B—C13B1.518 (2)
C8A—C13A1.520 (3)C8B—C9B1.520 (3)
C8A—H8AA0.98C8B—H8BA0.98
C9A—C10A1.532 (3)C9B—C10B1.527 (3)
C9A—H9AA0.97C9B—H9BA0.97
C9A—H9AB0.97C9B—H9BB0.97
C10A—C11A1.530 (3)C10B—C11B1.528 (3)
C10A—H10A0.97C10B—H10C0.97
C10A—H10B0.97C10B—H10D0.97
C11A—C12A1.519 (3)C11B—C12B1.515 (3)
C11A—H11A0.97C11B—H11C0.97
C11A—H11B0.97C11B—H11D0.97
C12A—C13A1.520 (2)C12B—C13B1.520 (3)
C12A—H12A0.98C12B—H12B0.98
C13A—H13A0.97C13B—H13C0.97
C13A—H13B0.97C13B—H13D0.97
C15A—C16A1.390 (3)C15B—C20B1.388 (3)
C15A—C20A1.393 (3)C15B—C16B1.390 (3)
C16A—C17A1.390 (3)C16B—C17B1.393 (3)
C16A—H16A0.93C16B—H16B0.93
C17A—C18A1.389 (3)C17B—C18B1.381 (4)
C17A—H17A0.93C17B—H17B0.93
C18A—C19A1.390 (3)C18B—C19B1.375 (3)
C18A—H18A0.93C18B—H18B0.93
C19A—C20A1.393 (3)C19B—C20B1.394 (3)
C19A—H19A0.93C19B—H19B0.93
C20A—H20A0.93C20B—H20B0.93
C7A—O2A—C8A117.89 (15)C7B—O2B—C8B117.06 (14)
C14A—O3A—C12A117.13 (15)C14B—O3B—C12B117.12 (14)
C7A—N1A—C6A125.41 (18)C7B—N1B—C6B127.13 (16)
C7A—N1A—H1NA112.3 (15)C7B—N1B—H1NB116.4 (17)
C6A—N1A—H1NA121.2 (15)C6B—N1B—H1NB116.2 (17)
C14A—N2A—C15A127.07 (16)C14B—N2B—C15B125.39 (18)
C14A—N2A—H2NA117.3 (18)C14B—N2B—H2NB115.7 (16)
C15A—N2A—H2NA114.6 (18)C15B—N2B—H2NB118.8 (16)
C2A—C1A—C6A119.43 (19)C2B—C1B—C6B119.5 (2)
C2A—C1A—H1AA120.3C2B—C1B—H1BA120.2
C6A—C1A—H1AA120.3C6B—C1B—H1BA120.2
C3A—C2A—C1A120.7 (2)C3B—C2B—C1B121.13 (19)
C3A—C2A—H2AA119.6C3B—C2B—H2BA119.4
C1A—C2A—H2AA119.6C1B—C2B—H2BA119.4
C2A—C3A—C4A119.8 (2)C4B—C3B—C2B119.13 (19)
C2A—C3A—H3AA120.1C4B—C3B—H3BA120.4
C4A—C3A—H3AA120.1C2B—C3B—H3BA120.4
C3A—C4A—C5A120.4 (2)C3B—C4B—C5B120.7 (2)
C3A—C4A—H4AA119.8C3B—C4B—H4BA119.6
C5A—C4A—H4AA119.8C5B—C4B—H4BA119.6
C4A—C5A—C6A119.6 (2)C4B—C5B—C6B119.94 (18)
C4A—C5A—H5AA120.2C4B—C5B—H5BA120.0
C6A—C5A—H5AA120.2C6B—C5B—H5BA120.0
C1A—C6A—C5A120.07 (19)C1B—C6B—C5B119.55 (18)
C1A—C6A—N1A122.74 (18)C1B—C6B—N1B123.52 (18)
C5A—C6A—N1A117.16 (19)C5B—C6B—N1B116.87 (16)
O1A—C7A—O2A124.28 (17)O1B—C7B—O2B124.40 (19)
O1A—C7A—N1A126.79 (19)O1B—C7B—N1B126.90 (18)
O2A—C7A—N1A108.94 (17)O2B—C7B—N1B108.70 (15)
O2A—C8A—C9A110.34 (15)O2B—C8B—C13B104.44 (15)
O2A—C8A—C13A104.39 (15)O2B—C8B—C9B111.20 (16)
C9A—C8A—C13A112.13 (17)C13B—C8B—C9B111.45 (15)
O2A—C8A—H8AA110.0O2B—C8B—H8BA109.9
C9A—C8A—H8AA110.0C13B—C8B—H8BA109.9
C13A—C8A—H8AA110.0C9B—C8B—H8BA109.9
C8A—C9A—C10A110.43 (16)C8B—C9B—C10B109.91 (16)
C8A—C9A—H9AA109.6C8B—C9B—H9BA109.7
C10A—C9A—H9AA109.6C10B—C9B—H9BA109.7
C8A—C9A—H9AB109.6C8B—C9B—H9BB109.7
C10A—C9A—H9AB109.6C10B—C9B—H9BB109.7
H9AA—C9A—H9AB108.1H9BA—C9B—H9BB108.2
C11A—C10A—C9A111.48 (16)C9B—C10B—C11B111.69 (16)
C11A—C10A—H10A109.3C9B—C10B—H10C109.3
C9A—C10A—H10A109.3C11B—C10B—H10C109.3
C11A—C10A—H10B109.3C9B—C10B—H10D109.3
C9A—C10A—H10B109.3C11B—C10B—H10D109.3
H10A—C10A—H10B108.0H10C—C10B—H10D107.9
C12A—C11A—C10A109.87 (17)C12B—C11B—C10B109.78 (16)
C12A—C11A—H11A109.7C12B—C11B—H11C109.7
C10A—C11A—H11A109.7C10B—C11B—H11C109.7
C12A—C11A—H11B109.7C12B—C11B—H11D109.7
C10A—C11A—H11B109.7C10B—C11B—H11D109.7
H11A—C11A—H11B108.2H11C—C11B—H11D108.2
O3A—C12A—C11A111.31 (16)O3B—C12B—C11B110.74 (15)
O3A—C12A—C13A104.54 (15)O3B—C12B—C13B103.88 (14)
C11A—C12A—C13A111.63 (16)C11B—C12B—C13B112.44 (16)
O3A—C12A—H12A109.7O3B—C12B—H12B109.9
C11A—C12A—H12A109.7C11B—C12B—H12B109.9
C13A—C12A—H12A109.7C13B—C12B—H12B109.9
C12A—C13A—C8A111.94 (16)C8B—C13B—C12B112.05 (16)
C12A—C13A—H13A109.2C8B—C13B—H13C109.2
C8A—C13A—H13A109.2C12B—C13B—H13C109.2
C12A—C13A—H13B109.2C8B—C13B—H13D109.2
C8A—C13A—H13B109.2C12B—C13B—H13D109.2
H13A—C13A—H13B107.9H13C—C13B—H13D107.9
O4A—C14A—O3A124.35 (19)O4B—C14B—N2B127.10 (19)
O4A—C14A—N2A126.63 (18)O4B—C14B—O3B124.41 (16)
O3A—C14A—N2A109.01 (16)N2B—C14B—O3B108.48 (16)
C16A—C15A—C20A119.49 (18)C20B—C15B—C16B119.92 (19)
C16A—C15A—N2A117.55 (17)C20B—C15B—N2B122.74 (18)
C20A—C15A—N2A122.91 (19)C16B—C15B—N2B117.30 (19)
C17A—C16A—C15A120.56 (19)C15B—C16B—C17B119.9 (2)
C17A—C16A—H16A119.7C15B—C16B—H16B120.1
C15A—C16A—H16A119.7C17B—C16B—H16B120.1
C18A—C17A—C16A120.3 (2)C18B—C17B—C16B120.0 (2)
C18A—C17A—H17A119.9C18B—C17B—H17B120.0
C16A—C17A—H17A119.9C16B—C17B—H17B120.0
C17A—C18A—C19A119.06 (19)C19B—C18B—C17B120.0 (2)
C17A—C18A—H18A120.5C19B—C18B—H18B120.0
C19A—C18A—H18A120.5C17B—C18B—H18B120.0
C18A—C19A—C20A121.02 (19)C18B—C19B—C20B120.6 (2)
C18A—C19A—H19A119.5C18B—C19B—H19B119.7
C20A—C19A—H19A119.5C20B—C19B—H19B119.7
C15A—C20A—C19A119.6 (2)C15B—C20B—C19B119.5 (2)
C15A—C20A—H20A120.2C15B—C20B—H20B120.3
C19A—C20A—H20A120.2C19B—C20B—H20B120.3
C6A—C1A—C2A—C3A0.6 (3)C6B—C1B—C2B—C3B0.5 (3)
C1A—C2A—C3A—C4A0.7 (3)C1B—C2B—C3B—C4B0.4 (3)
C2A—C3A—C4A—C5A1.2 (4)C2B—C3B—C4B—C5B0.1 (3)
C3A—C4A—C5A—C6A0.3 (3)C3B—C4B—C5B—C6B0.1 (3)
C2A—C1A—C6A—C5A1.5 (3)C2B—C1B—C6B—C5B0.3 (3)
C2A—C1A—C6A—N1A179.8 (2)C2B—C1B—C6B—N1B177.38 (19)
C4A—C5A—C6A—C1A1.1 (3)C4B—C5B—C6B—C1B0.0 (3)
C4A—C5A—C6A—N1A179.5 (2)C4B—C5B—C6B—N1B177.30 (18)
C7A—N1A—C6A—C1A34.4 (3)C7B—N1B—C6B—C1B18.0 (3)
C7A—N1A—C6A—C5A147.2 (2)C7B—N1B—C6B—C5B164.83 (19)
C8A—O2A—C7A—O1A7.5 (3)C8B—O2B—C7B—O1B1.0 (3)
C8A—O2A—C7A—N1A172.67 (16)C8B—O2B—C7B—N1B178.74 (16)
C6A—N1A—C7A—O1A5.5 (3)C6B—N1B—C7B—O1B3.8 (3)
C6A—N1A—C7A—O2A174.33 (18)C6B—N1B—C7B—O2B176.52 (18)
C7A—O2A—C8A—C9A99.4 (2)C7B—O2B—C8B—C13B157.19 (16)
C7A—O2A—C8A—C13A139.95 (17)C7B—O2B—C8B—C9B82.5 (2)
O2A—C8A—C9A—C10A169.92 (16)O2B—C8B—C9B—C10B171.80 (14)
C13A—C8A—C9A—C10A54.0 (2)C13B—C8B—C9B—C10B55.7 (2)
C8A—C9A—C10A—C11A56.4 (2)C8B—C9B—C10B—C11B57.9 (2)
C9A—C10A—C11A—C12A57.4 (2)C9B—C10B—C11B—C12B57.0 (2)
C14A—O3A—C12A—C11A83.1 (2)C14B—O3B—C12B—C11B93.5 (2)
C14A—O3A—C12A—C13A156.25 (17)C14B—O3B—C12B—C13B145.54 (16)
C10A—C11A—C12A—O3A172.51 (14)C10B—C11B—C12B—O3B170.03 (15)
C10A—C11A—C12A—C13A56.1 (2)C10B—C11B—C12B—C13B54.3 (2)
O3A—C12A—C13A—C8A174.99 (15)O2B—C8B—C13B—C12B174.04 (15)
C11A—C12A—C13A—C8A54.5 (2)C9B—C8B—C13B—C12B53.9 (2)
O2A—C8A—C13A—C12A172.95 (15)O3B—C12B—C13B—C8B173.31 (15)
C9A—C8A—C13A—C12A53.5 (2)C11B—C12B—C13B—C8B53.5 (2)
C12A—O3A—C14A—O4A0.2 (3)C15B—N2B—C14B—O4B3.0 (3)
C12A—O3A—C14A—N2A178.81 (16)C15B—N2B—C14B—O3B177.74 (18)
C15A—N2A—C14A—O4A5.8 (4)C12B—O3B—C14B—O4B9.2 (3)
C15A—N2A—C14A—O3A175.19 (18)C12B—O3B—C14B—N2B170.07 (16)
C14A—N2A—C15A—C16A165.8 (2)C14B—N2B—C15B—C20B33.7 (3)
C14A—N2A—C15A—C20A16.8 (3)C14B—N2B—C15B—C16B148.7 (2)
C20A—C15A—C16A—C17A1.4 (3)C20B—C15B—C16B—C17B0.8 (3)
N2A—C15A—C16A—C17A176.11 (19)N2B—C15B—C16B—C17B176.9 (2)
C15A—C16A—C17A—C18A1.0 (3)C15B—C16B—C17B—C18B1.9 (4)
C16A—C17A—C18A—C19A0.5 (3)C16B—C17B—C18B—C19B1.3 (4)
C17A—C18A—C19A—C20A1.5 (3)C17B—C18B—C19B—C20B0.3 (4)
C16A—C15A—C20A—C19A0.4 (3)C16B—C15B—C20B—C19B0.8 (3)
N2A—C15A—C20A—C19A176.97 (19)N2B—C15B—C20B—C19B178.4 (2)
C18A—C19A—C20A—C15A1.1 (3)C18B—C19B—C20B—C15B1.4 (4)
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of C15A–C20A and C1B–C6B phenyl rings, respectively.
D—H···AD—HH···AD···AD—H···A
N1A—H1NA···O1Ai0.83 (2)2.13 (2)2.953 (2)174 (2)
N2A—H2NA···O4Ai0.91 (3)2.09 (3)2.934 (2)154 (2)
N1B—H1NB···O1Bii0.93 (3)2.10 (3)2.920 (2)147 (2)
N2B—H2NB···O4Bii0.88 (3)2.02 (3)2.874 (2)163 (3)
C13A—H13B···Cg1iii0.972.863.734 (2)151
C13B—H13C···Cg2iv0.972.863.732 (2)150
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+3/2, z1/2; (iii) x+1, y, z+1; (iv) x, y+2, z.

Experimental details

Crystal data
Chemical formulaC20H22N2O4
Mr354.40
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)38.356 (7), 9.5453 (16), 9.8472 (16)
β (°) 91.034 (3)
V3)3604.7 (10)
Z8
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.55 × 0.15 × 0.13
Data collection
DiffractometerBruker APEXII DUO CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.951, 0.988
No. of measured, independent and
observed [I > 2σ(I)] reflections
30037, 10472, 6630
Rint0.057
(sin θ/λ)max1)0.703
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.064, 0.180, 1.08
No. of reflections10472
No. of parameters485
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.33, 0.25

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of C15A–C20A and C1B–C6B phenyl rings, respectively.
D—H···AD—HH···AD···AD—H···A
N1A—H1NA···O1Ai0.83 (2)2.13 (2)2.953 (2)174 (2)
N2A—H2NA···O4Ai0.91 (3)2.09 (3)2.934 (2)154 (2)
N1B—H1NB···O1Bii0.93 (3)2.10 (3)2.920 (2)147 (2)
N2B—H2NB···O4Bii0.88 (3)2.02 (3)2.874 (2)163 (3)
C13A—H13B···Cg1iii0.972.863.734 (2)151
C13B—H13C···Cg2iv0.972.863.732 (2)150
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x, y+3/2, z1/2; (iii) x+1, y, z+1; (iv) x, y+2, z.
 

Footnotes

Thomson Reuters ResearcherID: C-7576-2009.

§Thomson Reuters ResearcherID: A-3561-2009

Acknowledgements

The authors thank Universiti Sains Malaysia (USM) for the University Grant (No. 1001/PTEKIND/8140152). HKF and JHG thank USM for the Research University Golden Goose Grant (No. 1001/PFIZIK/811012). RMG and SHM thank USM for postdoctoral fellowships. JHG also thanks USM for a USM fellowship.

References

First citationBanerjee, S., Dutta, S. & Chakraborti, S. K. (1978). J. Indian Chem. Soc. 55, 284–286.  CAS Google Scholar
First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science Google Scholar
First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science Google Scholar
First citationGhalib, R. M., Sulaiman, O., Mehdi, S. H., Goh, J. H. & Fun, H.-K. (2010). Acta Cryst. E66, o1889–o1890.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationGraia, M., Raza Murad, G., Krimi Ammar, M., Mehdi, S. H. & Hashim, R. (2009). Acta Cryst. E65, o3231.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationIbuka, T., Chu, G. N., Aoyagi, T., Kitada, K., Tsukida, T. & Yoneda, F. (1985). Chem. Pharm. Bull. 33, 451–453.  CrossRef CAS Google Scholar
First citationLapidus, A. L., Pirozhkov, S. D., Kapkin, V. D. & Krylova, A. Y. (1987). Org. Tech. 13, 160.  Google Scholar
First citationLoev, B. & Kormendy, M. F. (1963). J. Org. Chem. 28, 3421–3426.  CrossRef CAS Google Scholar
First citationNiu, D. F., Zhang, L., Xiao, L. P., Luo, Y. W. & Lu, J. X. (2007). Appl. Organomet. Chem. 21, 941–944.  Web of Science CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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