Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The structure of the title compound, C15H15NO4, comprises a racemic mixture of chiral mol­ecules containing five stereogenic centres. The cyclo­hexane ring tends towards a boat conformation and the two tetra­hydro­furan rings adopt envelope conformations. Mol­ecules are linked into sheets parallel to (100) by a combination of O—H...O, C—H...O and C—H...π hydrogen bonds, leading to a two-dimensional supra­molecular structure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108000504/gd3181sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108000504/gd3181Isup2.hkl
Contains datablock I

CCDC reference: 681568

Comment top

The derivatives of exo-5,6-dehydronorcantharidin are of great pharmacological interest and have attracted considerable attention (Abel et al., 1996; Deng et al., 2005). Furthermore, molecules of this type containing nitrogen have become a hot topic in heterocyclic chemistry because of their antitumour, antiviral, analgesic, sedative and fungicidal activities (Salvati et al., 2005). We therefore become interested in the synthesis of the cantharidin analogue (II), with the possibility that biological activity is modified in the bicyclic imide systems. Compound (II) is generated from (I) in a single synthetic reduction by using Na(BH4). We report here the synthesis and the crystal structure of (II).

The regiochemistry of (II) was established by 1H and C NMR spectroscopy, and the diagnostic spin–spin interactions were identified with the aid of HH COSY experiments. The structure determination of (II) confirmed this connectivity and also established the exoposition with bridge H atoms of the molecule [please clarify]. The molecules of (II) are chiral, with five stereogenic centres at atoms C1, C2, C3, C6 and C7. Compound (II) crystallizes as a racemic mixture in space group P21/c. The reference molecule was selected to have S, S, R, S and R configurations at atoms C1, C2, C3, C6 and C7, respectively. Hence the racemic mixture consists of molecules whose configurations are 1S,2S,3R,6S,7R and 1R,2R,3S,6R,7S. The inter-bridgehead angles O3—C6—C7 and O3—C3—C2 of 100.44 (17) and 101.04 (16)°, respectively, are contracted with respect to the tetrahedral value, as is the C6—O3—C3 angle of 95.59 (15)°. The cyclohexane ring (C2–C7) adopts a boat conformation. The tetrahydrofuran rings (O3/C3/C2/C7/C6 and O3/C3/C4/C5/C6) have an envelope conformation with atom O3 as the flap atom, with puckering parameters (Cremer & Pople, 1975) of Q = 0.590 (2) Å, ϕ = 180.5 (2)°, Q = 0.508 (2) Å and ϕ = 359.4 (3)°, respectively. The maximum deviations of atom O3 from the planes defined by the remaining four atoms are 0.840 (1) and 0.755 (1) Å, respectively. The dihedral angle between the phenyl and imide rings is 29.28 (12)°. The methoxy substituent is approximately coplanar with the attached phenyl ring. The N—Caryl bond length is 1.428 (3) Å and is comparable to those found in previously reported structures (Trujillo-Ferrara et al., 2004; Miller et al., 2000; Ellis & Spek, 2001).

The supramolecular structure of (II) is composed of sheets generated by a combination of O—H···O, C—H···O and C—H···π hydrogen bonds (Table 1). The formation of the sheet is analyzed in terms of two different low-dimensional substructures. The first substructure is built using the O—H···O and C—H···π hydrogen bonds, where atoms O1 and C7 in the molecule at (x, y, z) act as hydrogen-bond donors, respectively, to atom O2 and the C9–C14 ring, both in the molecule at (-x + 1, y + 1/2, -z + 3/2), so forming C(6) (Bernstein et al., 1995) chains running parallel to the [010] direction (Fig. 2). The chains include only the molecules of 1S,2S,3R,6S,7R configuration. In the second substructure, atom C1 in the molecule at (x, y, z) (1S,2S,3R,6S,7R) acts as a hydrogen-bond donor to atom O3 in the molecule at (-x + 1, -y + 1, -z + 1) (1R,2R,3S,6R,7S), leading to a centrosymmetric R22(10) dimer centered at (1/2, 1/2, 1/2) (Fig. 3). The combination of these interactions generates a sheet parallel to (100). There are no direction-specific interactions between the sheets, so the supramolecular structure of the title compound is two-dimensional (Fig. 4).

Related literature top

For related literature, see: Abel et al. (1996); Bernstein et al. (1995); Cremer & Pople (1975); Deng et al. (2005); Ellis & Spek (2001); Hubert et al. (1975); Miller et al. (2000); Salvati et al. (2005); Trujillo-Ferrara et al. (2004).

Experimental top

The general synthetics procedure is described by Hubert et al. (1975). N-(4-Methoxyphenyl)-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, (I) (0.77 g, 2.84 mmol), prepared from furan and N-(4-methoxyphenyl)maleimide, was reduced in ethanol solution (250 ml) with 0.94 g of Na(BH4) added in small portions (at intervals of 15 min) at 252 K over a period of 2 h. The excess of Na(BH4) was destroyed in 15–30 min at 5 K above the reaction temperature by adding aqueous HCl (2 mol dm-3) until the pH reached 3.0. The mixture was stirred for an additional 45–60 min at the same temperature and poured into water. After extraction with dichloromethane, the organic layer was separated, dried over Na2(SO4) and filtered; the solvent was removed under reduced pressure to give a white solid that was purified by column chromatography [silica gel, n-hexane/ethyl acetate (1:2, v/v)] to give white crystals in 84% yield.

NMR (DMSO): δ(H) 2.11–2.13 (d, J = 7.02 Hz, 1H, H2), 2.73–2.75 (d, J = 7.02 Hz, 1H, H6), 3.72 (s, 3H, OCH3), 4.97 (s, 1H, H1), 5.10 (s, 1H, H7), 5.25–5.27 (d, J = 7.8 Hz, 1H, H5), 6.36–6.38 (d, J = 7.8 Hz, 1H, OH exchange with D2O), 6.44–6.48 (m, 2H, H8 and H9), 6.90–6.92 (d, J = 9.36 Hz, 2H, aromatic), 7.36–7.39 (d, J = 9.36 Hz, 2H, aromatic); δ(C) 47.42 (C6), 49.38 (C2), 55.72 (OCH3), 81.35 (C7), 82.56 (C1), 88.21 (C5), 114.84 (Car), 127.08 (Car), 136.80 (C8 and C9), 137.01 (Cq—N). FT–IR (KBr): ν 3347 (OH), 3074, 3021, 2954, 2934 and 2833, 1672 (CO), 1609 and 1513 (aromatic, CC), 1445, 1414, 1306, 1252 (C–OCH3), 1182 (C—O stretching), 1036 (C—N), 829 cm-1.

Refinement top

All H atoms bonded to C atoms were treated as riding atoms, with C—H distances in the range 0.93–0.98 Å and with Uiso(H) = kUeq(C), where k = 1.5 for the methyl group and 1.2 for all other H atoms. The position of the hydroxy H atom was obtained from a difference map, and its parameters were freely refined.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. Part of the crystal structure of (II), showing the formation of C(6) chains running parallel to [010]. For the sake of clarity, H atoms not involved in the motifs shown have been omitted. [Symmetry codes: (i) -x + 1, y + 1/2, - z + 3/2; (ii) -x + 1, y - 1/2, -z + 3/2.]
[Figure 3] Fig. 3. Part of the crystal structure of (II), showing the formation of an R22(10) dimer centred at (1/2, 1/2, 1/2). For the sake of clarity, H atoms not involved in the motifs shown have been omitted. [Symmetry codes: (iii) -x + 1, -y + 1, -z + 1.]
[Figure 4] Fig. 4. A stereoview of part of the crystal structure of (II), showing the formation of a hydrogen-bonded sheet parallel to (100). For the sake of clarity, H atoms not involved in the motifs shown have been omitted.
5-hydroxy-4-(4-methoxyphenyl)-10-oxa- 4-azatricyclo[5.2.1.02,6]dec-8-en-3-one top
Crystal data top
C15H15NO4F(000) = 576
Mr = 273.28Dx = 1.363 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 8698 reflections
a = 11.2076 (11) Åθ = 2.2–27.9°
b = 8.4910 (7) ŵ = 0.10 mm1
c = 14.1867 (15) ÅT = 293 K
β = 99.457 (8)°Prismatic stick, colorless
V = 1331.7 (2) Å30.60 × 0.32 × 0.05 mm
Z = 4
Data collection top
Stoe IPDSII
diffractometer
2600 independent reflections
Radiation source: fine-focus sealed tube1497 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.070
Detector resolution: 6.67 pixels mm-1θmax = 26.0°, θmin = 2.8°
rotation method scansh = 1313
Absorption correction: integration
(X-RED32; Stoe & Cie, 2002)
k = 1010
Tmin = 0.952, Tmax = 0.993l = 1717
9348 measured 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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.105H atoms treated by a mixture of independent and constrained refinement
S = 0.95 w = 1/[σ2(Fo2) + (0.0472P)2]
where P = (Fo2 + 2Fc2)/3
2600 reflections(Δ/σ)max < 0.001
185 parametersΔρmax = 0.14 e Å3
0 restraintsΔρmin = 0.16 e Å3
Crystal data top
C15H15NO4V = 1331.7 (2) Å3
Mr = 273.28Z = 4
Monoclinic, P21/cMo Kα radiation
a = 11.2076 (11) ŵ = 0.10 mm1
b = 8.4910 (7) ÅT = 293 K
c = 14.1867 (15) Å0.60 × 0.32 × 0.05 mm
β = 99.457 (8)°
Data collection top
Stoe IPDSII
diffractometer
2600 independent reflections
Absorption correction: integration
(X-RED32; Stoe & Cie, 2002)
1497 reflections with I > 2σ(I)
Tmin = 0.952, Tmax = 0.993Rint = 0.070
9348 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0460 restraints
wR(F2) = 0.105H atoms treated by a mixture of independent and constrained refinement
S = 0.95Δρmax = 0.14 e Å3
2600 reflectionsΔρmin = 0.16 e Å3
185 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
C10.4207 (2)0.7677 (2)0.58436 (14)0.0476 (5)
H10.39260.68720.53630.057*
C20.55500 (19)0.7981 (2)0.58383 (14)0.0480 (5)
H20.57070.90840.56970.058*
C30.6123 (2)0.6838 (2)0.51904 (15)0.0549 (6)
H30.56610.66980.45470.066*
C40.7415 (2)0.7338 (3)0.52216 (18)0.0653 (7)
H40.77440.78520.47450.078*
C50.7997 (2)0.6883 (3)0.60845 (19)0.0655 (6)
H50.88130.70060.63300.079*
C60.7044 (2)0.6135 (2)0.65641 (16)0.0558 (6)
H60.73490.54110.70860.067*
C70.6221 (2)0.7482 (2)0.68316 (14)0.0499 (5)
H70.66860.83480.71700.060*
C80.5260 (2)0.6884 (2)0.73519 (15)0.0510 (5)
C90.3055 (2)0.6507 (2)0.70667 (15)0.0481 (5)
C100.2817 (2)0.6759 (2)0.79729 (16)0.0590 (6)
H100.33750.73000.84130.071*
C110.1757 (2)0.6219 (3)0.82413 (17)0.0653 (7)
H110.16110.63830.88600.078*
C120.0916 (2)0.5435 (3)0.75853 (18)0.0631 (6)
C130.1142 (2)0.5210 (3)0.66735 (19)0.0681 (7)
H130.05740.46920.62280.082*
C140.2197 (2)0.5741 (3)0.64107 (16)0.0594 (6)
H140.23370.55860.57890.071*
C150.0454 (3)0.5065 (4)0.8657 (2)0.0981 (10)
H15A0.12150.45690.86920.147*
H15B0.05200.61770.87600.147*
H15C0.01600.46310.91380.147*
N10.41634 (17)0.70217 (19)0.67952 (11)0.0489 (4)
O10.34588 (15)0.89990 (18)0.56653 (11)0.0569 (4)
O20.54368 (16)0.63113 (19)0.81618 (11)0.0690 (5)
O30.62555 (14)0.54348 (15)0.57720 (10)0.0576 (4)
O40.01544 (17)0.4810 (3)0.77786 (14)0.0877 (6)
H1A0.375 (3)0.975 (4)0.607 (2)0.098 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0582 (15)0.0412 (10)0.0425 (10)0.0002 (9)0.0053 (9)0.0036 (8)
C20.0541 (15)0.0391 (10)0.0501 (12)0.0028 (9)0.0065 (10)0.0068 (9)
C30.0619 (16)0.0550 (12)0.0472 (12)0.0018 (11)0.0072 (10)0.0024 (10)
C40.0659 (18)0.0617 (14)0.0714 (16)0.0013 (12)0.0205 (13)0.0007 (12)
C50.0530 (16)0.0598 (14)0.0829 (17)0.0040 (12)0.0089 (13)0.0055 (13)
C60.0604 (16)0.0470 (11)0.0558 (13)0.0020 (10)0.0032 (11)0.0015 (10)
C70.0564 (15)0.0406 (10)0.0495 (12)0.0041 (9)0.0003 (10)0.0033 (9)
C80.0645 (16)0.0389 (10)0.0479 (12)0.0003 (10)0.0046 (11)0.0007 (9)
C90.0567 (15)0.0397 (10)0.0481 (12)0.0019 (9)0.0088 (10)0.0050 (9)
C100.0690 (17)0.0536 (13)0.0550 (14)0.0013 (11)0.0118 (12)0.0017 (10)
C110.0760 (19)0.0684 (14)0.0559 (14)0.0103 (13)0.0236 (13)0.0061 (11)
C120.0558 (17)0.0645 (14)0.0698 (17)0.0027 (12)0.0126 (12)0.0130 (12)
C130.0618 (18)0.0724 (15)0.0691 (16)0.0066 (13)0.0077 (13)0.0015 (13)
C140.0633 (17)0.0625 (13)0.0517 (13)0.0025 (12)0.0075 (11)0.0008 (11)
C150.075 (2)0.122 (3)0.106 (2)0.0089 (18)0.0394 (18)0.021 (2)
N10.0550 (12)0.0463 (9)0.0439 (9)0.0016 (8)0.0039 (8)0.0057 (8)
O10.0605 (11)0.0502 (9)0.0569 (9)0.0054 (8)0.0004 (8)0.0074 (7)
O20.0776 (13)0.0757 (10)0.0506 (9)0.0044 (8)0.0016 (8)0.0161 (8)
O30.0663 (11)0.0412 (8)0.0618 (9)0.0013 (7)0.0006 (8)0.0064 (7)
O40.0649 (13)0.1096 (15)0.0913 (14)0.0064 (11)0.0204 (11)0.0186 (12)
Geometric parameters (Å, º) top
C1—O11.399 (2)C8—O21.233 (2)
C1—N11.469 (2)C8—N11.353 (3)
C1—C21.528 (3)C9—C101.372 (3)
C1—H10.9800C9—C141.385 (3)
C2—C71.543 (3)C9—N11.428 (3)
C2—C31.547 (3)C10—C111.384 (3)
C2—H20.9800C10—H100.9300
C3—O31.443 (2)C11—C121.382 (4)
C3—C41.503 (3)C11—H110.9300
C3—H30.9800C12—C131.371 (3)
C4—C51.345 (3)C12—O41.380 (3)
C4—H40.9300C13—C141.374 (3)
C5—C61.498 (3)C13—H130.9300
C5—H50.9300C14—H140.9300
C6—O31.439 (3)C15—O41.360 (3)
C6—C71.555 (3)C15—H15A0.9600
C6—H60.9800C15—H15B0.9600
C7—C81.491 (3)C15—H15C0.9600
C7—H70.9800O1—H1A0.89 (3)
O1—C1—N1111.12 (16)C6—C7—H7112.5
O1—C1—C2115.18 (16)O2—C8—N1124.7 (2)
N1—C1—C2104.49 (16)O2—C8—C7125.3 (2)
O1—C1—H1108.6N1—C8—C7110.02 (17)
N1—C1—H1108.6C10—C9—C14118.8 (2)
C2—C1—H1108.6C10—C9—N1121.1 (2)
C1—C2—C7106.36 (16)C14—C9—N1120.0 (2)
C1—C2—C3113.74 (16)C9—C10—C11120.9 (2)
C7—C2—C3100.55 (16)C9—C10—H10119.5
C1—C2—H2111.8C11—C10—H10119.5
C7—C2—H2111.8C12—C11—C10119.7 (2)
C3—C2—H2111.8C12—C11—H11120.1
O3—C3—C4102.03 (18)C10—C11—H11120.1
O3—C3—C2101.04 (16)C13—C12—O4115.8 (2)
C4—C3—C2107.33 (17)C13—C12—C11119.4 (2)
O3—C3—H3114.9O4—C12—C11124.8 (2)
C4—C3—H3114.9C12—C13—C14120.7 (2)
C2—C3—H3114.9C12—C13—H13119.6
C5—C4—C3105.4 (2)C14—C13—H13119.6
C5—C4—H4127.3C13—C14—C9120.3 (2)
C3—C4—H4127.3C13—C14—H14119.8
C4—C5—C6105.1 (2)C9—C14—H14119.8
C4—C5—H5127.5O4—C15—H15A109.5
C6—C5—H5127.5O4—C15—H15B109.5
O3—C6—C5102.27 (18)H15A—C15—H15B109.5
O3—C6—C7100.44 (17)O4—C15—H15C109.5
C5—C6—C7107.15 (17)H15A—C15—H15C109.5
O3—C6—H6115.1H15B—C15—H15C109.5
C5—C6—H6115.1C8—N1—C9124.31 (17)
C7—C6—H6115.1C8—N1—C1113.88 (17)
C8—C7—C2105.22 (17)C9—N1—C1121.72 (17)
C8—C7—C6112.09 (17)C1—O1—H1A108.2 (19)
C2—C7—C6101.45 (16)C6—O3—C395.59 (15)
C8—C7—H7112.5C15—O4—C12118.3 (2)
C2—C7—H7112.5
O1—C1—C2—C7121.43 (18)C9—C10—C11—C121.0 (3)
N1—C1—C2—C70.76 (19)C10—C11—C12—C130.4 (4)
O1—C1—C2—C3128.85 (18)C10—C11—C12—O4178.2 (2)
N1—C1—C2—C3108.96 (17)O4—C12—C13—C14178.1 (2)
C1—C2—C3—O376.44 (19)C11—C12—C13—C140.6 (4)
C7—C2—C3—O336.82 (19)C12—C13—C14—C90.4 (4)
C1—C2—C3—C4177.10 (17)C10—C9—C14—C131.6 (3)
C7—C2—C3—C469.6 (2)N1—C9—C14—C13178.4 (2)
O3—C3—C4—C531.8 (2)O2—C8—N1—C90.6 (3)
C2—C3—C4—C574.0 (2)C7—C8—N1—C9177.79 (17)
C3—C4—C5—C60.7 (2)O2—C8—N1—C1177.26 (19)
C4—C5—C6—O333.1 (2)C7—C8—N1—C11.1 (2)
C4—C5—C6—C772.1 (2)C10—C9—N1—C841.8 (3)
C1—C2—C7—C81.4 (2)C14—C9—N1—C8138.2 (2)
C3—C2—C7—C8117.42 (17)C10—C9—N1—C1141.7 (2)
C1—C2—C7—C6118.28 (17)C14—C9—N1—C138.2 (3)
C3—C2—C7—C60.5 (2)O1—C1—N1—C8125.01 (19)
O3—C6—C7—C875.8 (2)C2—C1—N1—C80.2 (2)
C5—C6—C7—C8177.73 (18)O1—C1—N1—C958.2 (2)
O3—C6—C7—C236.0 (2)C2—C1—N1—C9176.96 (16)
C5—C6—C7—C270.5 (2)C5—C6—O3—C350.66 (19)
C2—C7—C8—O2176.83 (18)C7—C6—O3—C359.65 (18)
C6—C7—C8—O267.4 (3)C4—C3—O3—C650.03 (19)
C2—C7—C8—N11.5 (2)C2—C3—O3—C660.58 (18)
C6—C7—C8—N1110.95 (19)C13—C12—O4—C15176.8 (3)
C14—C9—C10—C111.9 (3)C11—C12—O4—C154.6 (4)
N1—C9—C10—C11178.1 (2)

Experimental details

Crystal data
Chemical formulaC15H15NO4
Mr273.28
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)11.2076 (11), 8.4910 (7), 14.1867 (15)
β (°) 99.457 (8)
V3)1331.7 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.60 × 0.32 × 0.05
Data collection
DiffractometerStoe IPDSII
diffractometer
Absorption correctionIntegration
(X-RED32; Stoe & Cie, 2002)
Tmin, Tmax0.952, 0.993
No. of measured, independent and
observed [I > 2σ(I)] reflections
9348, 2600, 1497
Rint0.070
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.105, 0.95
No. of reflections2600
No. of parameters185
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.14, 0.16

Computer programs: X-AREA (Stoe & Cie, 2002), X-RED32 (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996) and PLATON (Spek, 2003), WinGX (Farrugia, 1999).

Intermolecular hydrogen-bond interactions (Å,°) top
D-H···AD-HH···AD···AD-H···A
O1-H1A···O2i0.89 (3)1.85 (3)2.735 (2)172 (3)
C1-H1···O3iii0.982.523.480 (2)165.5
C7-H7···Cgi0.982.723.676 (2)166
Cg is the centroid of the C9–C14 ring. Symmetry codes: (i) -x+1, y+1/2, -z+3/2; (iii) -x+1, -y+1, -z+1.
 

Subscribe to Acta Crystallographica Section C: Structural Chemistry

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds