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ISSN: 2056-9890

Ethyl 2-phenyl-5,6-di­hydro­pyrrolo­[2,1-a]iso­quinoline-3-carboxyl­ate

aSchool of Chemistry and Chemical Engineering, Linyi University, Linyi, Shandong 276005, People's Republic of China, bDepartment of Chemistry, Huainan Union University, Huainan 232038, People's Republic of China, and cDepartment of Chemistry, University of Science and Technology of China, 230026 Hefei, People's Republic of China
*Correspondence e-mail: yuzp@mail.ustc.edu.cn

(Received 28 May 2012; accepted 31 May 2012; online 13 June 2012)

In the title compound, C21H19NO2, the six-membered heterocycle assumes a screw-boat conformation. The phenyl ring is oriented with respect to the pyrrole ring at a dihedral angle of 64.76 (10)°. An intra­molecular C—H⋯O hydrogen bond helps to stabilize the mol­ecular structure. There are weak C—H⋯π inter­actions between inversion-related mol­ecules in the crystal.

Related literature

For background and applications of lamellarins, see: Bailly (2004[Bailly, C. (2004). Curr. Med. Chem. Anticancer Agents, 4, 363-378.]); Zou et al. (2011[Zou, Y.-Q., Lu, L.-Q., Fu, L., Chang, N.-J., Rong, J., Chen, J.-R. & Xiao, W.-J. (2011). Angew. Chem. Int. Ed. 50, 7171-7175.]). For a related compound, see: Feng et al. (2012[Feng, C.-T., Wang, L.-D., Yan, Y.-G., Liu, J. & Li, S.-H. (2012). Med. Chem. Res. 21, 315-320.]).

[Scheme 1]

Experimental

Crystal data
  • C21H19NO2

  • Mr = 317.37

  • Triclinic, [P \overline 1]

  • a = 8.1527 (6) Å

  • b = 8.4029 (6) Å

  • c = 12.4220 (8) Å

  • α = 100.117 (6)°

  • β = 101.155 (5)°

  • γ = 94.312 (6)°

  • V = 816.66 (10) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 291 K

  • 0.42 × 0.37 × 0.32 mm

Data collection
  • Oxford Diffraction Gemini S Ultra diffractometer

  • 6799 measured reflections

  • 3340 independent reflections

  • 2233 reflections with I > 2σ(I)

  • Rint = 0.027

Refinement
  • R[F2 > 2σ(F2)] = 0.047

  • wR(F2) = 0.117

  • S = 1.02

  • 3340 reflections

  • 218 parameters

  • H-atom parameters constrained

  • Δρmax = 0.14 e Å−3

  • Δρmin = −0.18 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the pyrrole ring.

D—H⋯A D—H H⋯A DA D—H⋯A
C8—H8A⋯O1 0.97 2.29 2.913 (2) 121
C8—H8BCg1i 0.97 2.69 3.6411 (19) 166
Symmetry code: (i) -x+1, -y+1, -z+2.

Data collection: CrysAlis PRO (Oxford Diffraction, 2007[Oxford Diffraction (2007). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Lamellarin alkaloids, a new family of marine natural products that contain a pyrrolo[2,1-a]isoquinoline core, were found to exhibit a wide spectrum of biological activities (Bailly, 2004). Natural as well as synthetic lamellarins should be excellent candidates for the development of new drugs due to their unique skeletal structure and their important biological activities especially as antitumor agents (Zou et al., 2011). As part of our previous studies concerning anticancer agents, we here report a crystal structure of open chain analogues of lamellarins (Feng et al., 2012).

The conformational analysis show that the conformation of 6-membered hetero-ring is screw boat. The phenyl ring is oriented with respect to the pyrrole ring at 64.76 (10)°. An intramolecular C—H···O hydrogen bond helps to stabilize the molecular structure. There is weak C—H···π interaction between inversion-related molecules in the crystal.

Related literature top

For background and applications of lamellarins, see: Bailly (2004); Zou et al. (2011). For a related compound, see: Feng et al. (2012).

Experimental top

Synthesis or separation ??

Colourless blocky single crystals of the title compound suitable for X-ray diffraction analysis were obtained by slow evaporation of the mixed solvent ethanol/CH2Cl2 (2:1, v/v) at room temperature for five days.

Refinement top

H atoms were positioned geometrically and allowed to ride on their parent atoms with C—H = 0.93–0.97 Å, Uiso(H) = 1.5Ueq(C) for methyl H atoms and 1.2Ueq(C) for the others.

Structure description top

Lamellarin alkaloids, a new family of marine natural products that contain a pyrrolo[2,1-a]isoquinoline core, were found to exhibit a wide spectrum of biological activities (Bailly, 2004). Natural as well as synthetic lamellarins should be excellent candidates for the development of new drugs due to their unique skeletal structure and their important biological activities especially as antitumor agents (Zou et al., 2011). As part of our previous studies concerning anticancer agents, we here report a crystal structure of open chain analogues of lamellarins (Feng et al., 2012).

The conformational analysis show that the conformation of 6-membered hetero-ring is screw boat. The phenyl ring is oriented with respect to the pyrrole ring at 64.76 (10)°. An intramolecular C—H···O hydrogen bond helps to stabilize the molecular structure. There is weak C—H···π interaction between inversion-related molecules in the crystal.

For background and applications of lamellarins, see: Bailly (2004); Zou et al. (2011). For a related compound, see: Feng et al. (2012).

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell refinement: CrysAlis PRO (Oxford Diffraction, 2007); data reduction: CrysAlis PRO (Oxford Diffraction, 2007); 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); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with displacement ellipsoids drawn at the 45% probability level.
Ethyl 2-phenyl-5,6-dihydropyrrolo[2,1-a]isoquinoline-3-carboxylate top
Crystal data top
C21H19NO2Z = 2
Mr = 317.37F(000) = 336
Triclinic, P1Dx = 1.291 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.1527 (6) ÅCell parameters from 1649 reflections
b = 8.4029 (6) Åθ = 3.3–29.0°
c = 12.4220 (8) ŵ = 0.08 mm1
α = 100.117 (6)°T = 291 K
β = 101.155 (5)°Block, colourless
γ = 94.312 (6)°0.42 × 0.37 × 0.32 mm
V = 816.66 (10) Å3
Data collection top
Oxford Diffraction Gemini S Ultra
diffractometer
2233 reflections with I > 2σ(I)
Radiation source: Enhance (Mo) X-ray SourceRint = 0.027
Graphite monochromatorθmax = 26.4°, θmin = 3.3°
Detector resolution: 15.9149 pixels mm-1h = 910
ω scansk = 1010
6799 measured reflectionsl = 1515
3340 independent reflections
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)] = 0.047Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.117H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0468P)2 + 0.0731P]
where P = (Fo2 + 2Fc2)/3
3340 reflections(Δ/σ)max < 0.001
218 parametersΔρmax = 0.14 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C21H19NO2γ = 94.312 (6)°
Mr = 317.37V = 816.66 (10) Å3
Triclinic, P1Z = 2
a = 8.1527 (6) ÅMo Kα radiation
b = 8.4029 (6) ŵ = 0.08 mm1
c = 12.4220 (8) ÅT = 291 K
α = 100.117 (6)°0.42 × 0.37 × 0.32 mm
β = 101.155 (5)°
Data collection top
Oxford Diffraction Gemini S Ultra
diffractometer
2233 reflections with I > 2σ(I)
6799 measured reflectionsRint = 0.027
3340 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0470 restraints
wR(F2) = 0.117H-atom parameters constrained
S = 1.02Δρmax = 0.14 e Å3
3340 reflectionsΔρmin = 0.18 e Å3
218 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
xyzUiso*/Ueq
N10.42666 (15)0.27334 (17)0.95299 (10)0.0434 (4)
O10.77604 (15)0.2297 (2)1.03663 (11)0.0740 (5)
O20.69802 (14)0.16479 (18)1.18676 (10)0.0631 (4)
C50.1606 (2)0.3304 (2)0.84460 (13)0.0443 (4)
C180.2738 (2)0.0419 (2)1.23460 (15)0.0539 (5)
H180.21350.03031.17140.065*
C80.5153 (2)0.3175 (2)0.86845 (13)0.0505 (5)
H8A0.61670.26370.87050.061*
H8B0.54750.43410.88400.061*
C120.49185 (19)0.2354 (2)1.05503 (13)0.0434 (4)
C130.3623 (2)0.1813 (2)1.22237 (13)0.0454 (4)
C100.2142 (2)0.2488 (2)1.03899 (13)0.0480 (4)
H100.10650.24551.05370.058*
C110.3589 (2)0.2190 (2)1.10987 (13)0.0447 (4)
C60.0014 (2)0.3795 (2)0.84292 (14)0.0536 (5)
H60.04530.38290.90580.064*
C10.0877 (2)0.4233 (2)0.74877 (15)0.0600 (5)
H10.19420.45630.74820.072*
C90.25855 (19)0.2840 (2)0.94354 (13)0.0439 (4)
C170.2729 (3)0.0075 (3)1.33909 (17)0.0671 (6)
H170.21360.08791.34580.080*
C40.2309 (2)0.3253 (2)0.74989 (13)0.0488 (4)
C200.8689 (2)0.1447 (3)1.23534 (15)0.0621 (5)
H20B0.94600.23071.22380.075*
H20A0.89830.04091.20100.075*
C160.3596 (3)0.1139 (3)1.43305 (17)0.0696 (6)
H160.35900.09081.50350.084*
C140.4485 (2)0.2875 (3)1.31825 (15)0.0610 (5)
H140.50850.38291.31200.073*
C150.4469 (3)0.2539 (3)1.42279 (15)0.0708 (6)
H150.50520.32661.48640.085*
C70.4011 (2)0.2665 (2)0.75443 (13)0.0556 (5)
H7A0.45380.30890.70010.067*
H7B0.38730.14870.73380.067*
C190.6685 (2)0.2107 (2)1.08874 (14)0.0474 (4)
C30.1386 (2)0.3693 (2)0.65604 (15)0.0610 (5)
H30.18370.36580.59250.073*
C20.0192 (3)0.4181 (3)0.65534 (16)0.0646 (5)
H20.07960.44760.59170.077*
C210.8791 (3)0.1518 (3)1.35720 (17)0.0809 (7)
H21A0.80390.06491.36750.121*
H21B0.84790.25431.39000.121*
H21C0.99210.14081.39260.121*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0427 (7)0.0525 (9)0.0368 (8)0.0057 (6)0.0130 (6)0.0080 (6)
O10.0462 (7)0.1197 (14)0.0634 (9)0.0135 (8)0.0206 (6)0.0257 (8)
O20.0443 (7)0.0917 (11)0.0587 (8)0.0135 (7)0.0087 (6)0.0292 (7)
C50.0485 (9)0.0444 (11)0.0373 (9)0.0012 (8)0.0068 (7)0.0047 (7)
C180.0594 (11)0.0530 (12)0.0541 (11)0.0124 (9)0.0195 (9)0.0124 (9)
C80.0518 (10)0.0596 (12)0.0454 (10)0.0072 (9)0.0218 (8)0.0115 (9)
C120.0434 (9)0.0488 (11)0.0396 (9)0.0073 (8)0.0117 (7)0.0090 (8)
C130.0432 (9)0.0564 (12)0.0411 (10)0.0138 (8)0.0133 (7)0.0130 (8)
C100.0416 (9)0.0614 (12)0.0429 (10)0.0067 (8)0.0130 (7)0.0107 (8)
C110.0452 (9)0.0502 (11)0.0405 (9)0.0077 (8)0.0122 (7)0.0094 (8)
C60.0510 (10)0.0624 (13)0.0461 (10)0.0072 (9)0.0094 (8)0.0080 (9)
C10.0551 (11)0.0656 (14)0.0553 (11)0.0085 (9)0.0009 (9)0.0125 (10)
C90.0432 (9)0.0487 (11)0.0395 (9)0.0042 (8)0.0108 (7)0.0057 (8)
C170.0864 (14)0.0631 (14)0.0653 (14)0.0175 (11)0.0318 (11)0.0274 (11)
C40.0575 (10)0.0492 (11)0.0375 (9)0.0010 (8)0.0090 (8)0.0057 (8)
C200.0442 (10)0.0721 (15)0.0652 (13)0.0141 (9)0.0003 (9)0.0098 (10)
C160.0869 (15)0.0860 (17)0.0510 (12)0.0336 (13)0.0261 (11)0.0304 (12)
C140.0657 (12)0.0681 (14)0.0482 (11)0.0001 (10)0.0126 (9)0.0115 (10)
C150.0806 (14)0.0864 (18)0.0420 (11)0.0104 (12)0.0088 (10)0.0075 (11)
C70.0629 (11)0.0663 (13)0.0407 (10)0.0068 (10)0.0198 (8)0.0093 (9)
C190.0468 (10)0.0487 (11)0.0456 (10)0.0046 (8)0.0112 (8)0.0050 (8)
C30.0706 (13)0.0690 (14)0.0427 (11)0.0028 (10)0.0107 (9)0.0128 (9)
C20.0707 (13)0.0690 (15)0.0501 (11)0.0055 (11)0.0030 (10)0.0193 (10)
C210.0661 (13)0.103 (2)0.0663 (14)0.0083 (12)0.0041 (10)0.0175 (13)
Geometric parameters (Å, º) top
N1—C91.3639 (19)C6—H60.9300
N1—C121.3775 (19)C1—C21.377 (3)
N1—C81.4675 (18)C1—H10.9300
O1—C191.2036 (19)C17—C161.371 (3)
O2—C191.325 (2)C17—H170.9300
O2—C201.442 (2)C4—C31.384 (2)
C5—C61.389 (2)C4—C71.502 (2)
C5—C41.401 (2)C20—C211.490 (2)
C5—C91.461 (2)C20—H20B0.9700
C18—C131.376 (2)C20—H20A0.9700
C18—C171.380 (2)C16—C151.367 (3)
C18—H180.9300C16—H160.9300
C8—C71.508 (2)C14—C151.379 (2)
C8—H8A0.9700C14—H140.9300
C8—H8B0.9700C15—H150.9300
C12—C111.398 (2)C7—H7A0.9700
C12—C191.461 (2)C7—H7B0.9700
C13—C141.385 (2)C3—C21.379 (3)
C13—C111.482 (2)C3—H30.9300
C10—C91.377 (2)C2—H20.9300
C10—C111.396 (2)C21—H21A0.9600
C10—H100.9300C21—H21B0.9600
C6—C11.376 (2)C21—H21C0.9600
C9—N1—C12109.29 (12)C3—C4—C5118.70 (17)
C9—N1—C8121.26 (13)C3—C4—C7123.36 (15)
C12—N1—C8129.05 (13)C5—C4—C7117.91 (14)
C19—O2—C20118.09 (13)O2—C20—C21107.19 (15)
C6—C5—C4119.82 (15)O2—C20—H20B110.3
C6—C5—C9121.65 (14)C21—C20—H20B110.3
C4—C5—C9118.53 (15)O2—C20—H20A110.3
C13—C18—C17121.11 (18)C21—C20—H20A110.3
C13—C18—H18119.4H20B—C20—H20A108.5
C17—C18—H18119.4C15—C16—C17119.77 (18)
N1—C8—C7109.17 (13)C15—C16—H16120.1
N1—C8—H8A109.8C17—C16—H16120.1
C7—C8—H8A109.8C15—C14—C13120.98 (19)
N1—C8—H8B109.8C15—C14—H14119.5
C7—C8—H8B109.8C13—C14—H14119.5
H8A—C8—H8B108.3C16—C15—C14120.1 (2)
N1—C12—C11107.38 (13)C16—C15—H15120.0
N1—C12—C19122.42 (13)C14—C15—H15120.0
C11—C12—C19130.12 (15)C4—C7—C8112.81 (14)
C18—C13—C14117.99 (15)C4—C7—H7A109.0
C18—C13—C11120.63 (16)C8—C7—H7A109.0
C14—C13—C11121.33 (16)C4—C7—H7B109.0
C9—C10—C11108.17 (14)C8—C7—H7B109.0
C9—C10—H10125.9H7A—C7—H7B107.8
C11—C10—H10125.9O1—C19—O2123.10 (16)
C10—C11—C12107.05 (14)O1—C19—C12125.80 (16)
C10—C11—C13124.05 (14)O2—C19—C12111.10 (14)
C12—C11—C13128.89 (14)C2—C3—C4121.00 (17)
C1—C6—C5120.41 (16)C2—C3—H3119.5
C1—C6—H6119.8C4—C3—H3119.5
C5—C6—H6119.8C1—C2—C3120.08 (17)
C6—C1—C2119.99 (18)C1—C2—H2120.0
C6—C1—H1120.0C3—C2—H2120.0
C2—C1—H1120.0C20—C21—H21A109.5
N1—C9—C10108.09 (14)C20—C21—H21B109.5
N1—C9—C5120.21 (13)H21A—C21—H21B109.5
C10—C9—C5131.69 (15)C20—C21—H21C109.5
C16—C17—C18120.0 (2)H21A—C21—H21C109.5
C16—C17—H17120.0H21B—C21—H21C109.5
C18—C17—H17120.0
C9—N1—C8—C736.6 (2)C4—C5—C9—N115.1 (2)
C12—N1—C8—C7151.50 (17)C6—C5—C9—C1013.7 (3)
C9—N1—C12—C111.12 (19)C4—C5—C9—C10166.59 (18)
C8—N1—C12—C11173.80 (16)C13—C18—C17—C160.8 (3)
C9—N1—C12—C19178.10 (15)C6—C5—C4—C30.2 (3)
C8—N1—C12—C199.2 (3)C9—C5—C4—C3179.93 (16)
C17—C18—C13—C141.0 (3)C6—C5—C4—C7178.17 (16)
C17—C18—C13—C11178.47 (16)C9—C5—C4—C72.1 (2)
C9—C10—C11—C120.5 (2)C19—O2—C20—C21160.33 (17)
C9—C10—C11—C13178.27 (16)C18—C17—C16—C150.1 (3)
N1—C12—C11—C100.3 (2)C18—C13—C14—C150.5 (3)
C19—C12—C11—C10177.02 (18)C11—C13—C14—C15177.98 (16)
N1—C12—C11—C13179.07 (17)C17—C16—C15—C140.4 (3)
C19—C12—C11—C134.3 (3)C13—C14—C15—C160.2 (3)
C18—C13—C11—C1063.7 (2)C3—C4—C7—C8146.38 (18)
C14—C13—C11—C10113.6 (2)C5—C4—C7—C835.8 (2)
C18—C13—C11—C12117.7 (2)N1—C8—C7—C451.0 (2)
C14—C13—C11—C1264.9 (3)C20—O2—C19—O13.1 (3)
C4—C5—C6—C10.0 (3)C20—O2—C19—C12176.31 (15)
C9—C5—C6—C1179.69 (17)N1—C12—C19—O14.8 (3)
C5—C6—C1—C20.1 (3)C11—C12—C19—O1178.94 (18)
C12—N1—C9—C101.46 (19)N1—C12—C19—O2175.75 (15)
C8—N1—C9—C10174.81 (15)C11—C12—C19—O20.5 (3)
C12—N1—C9—C5177.22 (15)C5—C4—C3—C20.3 (3)
C8—N1—C9—C53.9 (2)C7—C4—C3—C2178.15 (17)
C11—C10—C9—N11.2 (2)C6—C1—C2—C30.0 (3)
C11—C10—C9—C5177.24 (18)C4—C3—C2—C10.2 (3)
C6—C5—C9—N1164.60 (16)
Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the pyrrole ring.
D—H···AD—HH···AD···AD—H···A
C8—H8A···O10.972.292.913 (2)121
C8—H8B···Cg1i0.972.693.6411 (19)166
Symmetry code: (i) x+1, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC21H19NO2
Mr317.37
Crystal system, space groupTriclinic, P1
Temperature (K)291
a, b, c (Å)8.1527 (6), 8.4029 (6), 12.4220 (8)
α, β, γ (°)100.117 (6), 101.155 (5), 94.312 (6)
V3)816.66 (10)
Z2
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.42 × 0.37 × 0.32
Data collection
DiffractometerOxford Diffraction Gemini S Ultra
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
6799, 3340, 2233
Rint0.027
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.047, 0.117, 1.02
No. of reflections3340
No. of parameters218
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.14, 0.18

Computer programs: CrysAlis PRO (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the pyrrole ring.
D—H···AD—HH···AD···AD—H···A
C8—H8A···O10.972.292.913 (2)121
C8—H8B···Cg1i0.972.693.6411 (19)166
Symmetry code: (i) x+1, y+1, z+2.
 

Acknowledgements

This work was supported by the Natural Science Foundation of the Higher Education Institutions of the Education Bureau of Anhui Province (grant No. KJ2011B154), the Science and Technology Planning Project of Huainan (grant No. 2011 A08101) and Huainan Union University, China (grant No. LYB1005).

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