Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The title compound, C23H23N3O, has a supramolecular structure of hydrogen bonding comprising N—H...O bonds which form a series of anti-parallel C(8) chains linked together by N—H...N R22(8) base-paired motifs which together form corrugated sheets containing R66(34) rings. This is one of a series of four substituted 3,7,7-tri­methyl-4,7,8,9-tetra­hydro-2H-pyrazolo­[3,4-b]­quinolin-5(6H)-one compounds which all have identical supramolecular structures.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801001489/na6039sup1.cif
Contains datablocks global, 1

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801001489/na6039Isup2.hkl
Contains datablock I

CCDC reference: 159753

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.051
  • wR factor = 0.137
  • Data-to-parameter ratio = 18.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry




Comment top

Pyrazolo[3,4-b]quinolines are of interest as possible antiviral agents (Crenshaw et al., 1976, 1978; Smirnoff & Crenshaw, 1977). Some of their derivatives exhibit parasiticidic properties (Bristol-Meyers Co, 1973), and have been studied as potential antimalarial agents (Stein et al., 1970). Some pyrazolo[3,4-b]quinolines have shown bactericidal activity (Farghaly et al., 1989), have also been used as vasodilators (Bell & Ackerman, 1990) and evaluated for enzymatic inhibitory activity (Gatta et al., 1991).

In previous reports (Quiroga, Hormaza et al., 1998; Quiroga, Insuasty et al., 1998), we have reported an efficient and versatile synthesis of novel 4,7,8,9-tetrahydro-pyrimido- and 4,7,8,9-tetrahydropyrazolo[3,4-b]quinolin-5-ones from suitable pyrimidine and pyrazole amines to which dimedone and substituted benzaldehyde afford the ring annelation to quinoline.

Selected bonds and angles for the title compound, (I), are given in Table 1 and a molecular view is given in Fig. 1.

The hydrogen-bonding pattern comprises anti-parallel C(8) (N2–H2···O51i) chains linked together by R22(8) (N9–H9···N1ii) base-paired motifs (Bernstein et al., 1995). This combination forms a corrugated sheet which contains R66(34) rings. This is shown in Fig. 2. The details of the hydrogen bonds are given in Table 2.

Examination of the structure with PLATON (Spek, 2000) showed that there were no solvent-accessible voids in the crystal lattice.

Experimental top

A solution of 5-aminopyrazole (1 mmol), dimedone, (1 mmol) and 2-naphthaldehyde (1 mmol) in 15 ml of absolute ethanol were heated to reflux for 20–50 min (thin-layer chromatography control control). The reaction mixture was cooled and the solid corresponding to the title compound was filtered out, washed with ethanol, dried and recrystallized from ethanol to afford suitable crystals for diffraction. 65% yield, m.p. 602 K).

Refinement top

H atoms were treated as riding atoms, with C—H = 0.95–1.00 Å and N—H = 0.88 Å.

Computing details top

Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976) and PLATON (Spek, 2000); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PRPKAPPA (Ferguson, 1999).

Figures top
[Figure 1] Fig. 1. A view of the molecule with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. View of the hydrogen-bonded sheets lying parallel to [010] showing the C(8) chains, the R22(8) rings and the R88(34) rings. Atom O51i is at (0.5 - x, 0.5 + y, 1.5 - z) and atom N1ii is at (-x, 1 - y, 2 - z).
3,7,7-Trimethyl-4-(β-naphthyl)-4,7,8,9-tetrahydro-2H-pyrazolo[3,4-b]- quinolin-5(6H)-one top
Crystal data top
C23H23N3ODx = 1.236 Mg m3
Mr = 357.44Melting point: 602 K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 9.1222 (18) ÅCell parameters from 4401 reflections
b = 15.281 (3) Åθ = 2.0–27.6°
c = 14.346 (3) ŵ = 0.08 mm1
β = 106.13 (3)°T = 150 K
V = 1921.0 (7) Å3Block, colourless
Z = 40.35 × 0.18 × 0.14 mm
F(000) = 760
Data collection top
KappaCCD
diffractometer
4401 independent reflections
Radiation source: fine-focus sealed X-ray tube2994 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.062
ϕ and ω scans with κ offsetsθmax = 27.6°, θmin = 2.0°
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
h = 1111
Tmin = 0.974, Tmax = 0.989k = 1919
16205 measured reflectionsl = 1818
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)] = 0.051Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.137H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0763P)2]
where P = (Fo2 + 2Fc2)/3
4401 reflections(Δ/σ)max < 0.001
245 parametersΔρmax = 0.23 e Å3
0 restraintsΔρmin = 0.28 e Å3
Crystal data top
C23H23N3OV = 1921.0 (7) Å3
Mr = 357.44Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.1222 (18) ŵ = 0.08 mm1
b = 15.281 (3) ÅT = 150 K
c = 14.346 (3) Å0.35 × 0.18 × 0.14 mm
β = 106.13 (3)°
Data collection top
KappaCCD
diffractometer
4401 independent reflections
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
2994 reflections with I > 2σ(I)
Tmin = 0.974, Tmax = 0.989Rint = 0.062
16205 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0510 restraints
wR(F2) = 0.137H-atom parameters constrained
S = 1.03Δρmax = 0.23 e Å3
4401 reflectionsΔρmin = 0.28 e Å3
245 parameters
Special details top

Experimental. The program DENZO-SMN (Otwinowski & Minor, 1997) uses a scaling algorithm (Fox & Holmes, 1966) which effectively corrects for absorption effects. High redundancy data were used in the scaling program hence the 'multi-scan' code word was used. no transmission coefficients are available from the program (only scale factors for each frame). The scale factors in the experimental table are calculated from the 'size' command in the SHELXL97 input file.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.08690 (15)0.49567 (8)0.87092 (9)0.0266 (3)
N20.14671 (14)0.50100 (8)0.77261 (9)0.0271 (3)
C30.11695 (17)0.43020 (10)0.72492 (11)0.0259 (4)
C310.1677 (2)0.42393 (12)0.61717 (11)0.0358 (4)
C3A0.03500 (17)0.37374 (10)0.79488 (11)0.0245 (3)
C40.02769 (17)0.28315 (9)0.79326 (11)0.0236 (3)
C410.13242 (18)0.15730 (10)0.70697 (11)0.0275 (4)
C420.09687 (18)0.21414 (10)0.78258 (11)0.0250 (3)
C430.17867 (19)0.20933 (11)0.85316 (12)0.0310 (4)
C440.2933 (2)0.15026 (11)0.84482 (12)0.0338 (4)
C450.45556 (19)0.03165 (11)0.75382 (13)0.0362 (4)
C460.4903 (2)0.02461 (11)0.67764 (13)0.0407 (5)
C470.4042 (2)0.02429 (12)0.61067 (14)0.0429 (5)
C480.2890 (2)0.03424 (11)0.61845 (13)0.0368 (4)
C48A0.25077 (17)0.09393 (10)0.69594 (11)0.0273 (4)
C44A0.33384 (18)0.09171 (10)0.76635 (11)0.0300 (4)
C4A0.15391 (17)0.27030 (9)0.88723 (10)0.0233 (3)
C50.26617 (17)0.20408 (9)0.88870 (11)0.0240 (3)
O510.26432 (13)0.15970 (7)0.81623 (8)0.0308 (3)
C60.39283 (18)0.19092 (10)0.98122 (11)0.0274 (4)
C70.34492 (17)0.20762 (9)1.07350 (11)0.0253 (4)
C710.48401 (19)0.20359 (11)1.16209 (12)0.0330 (4)
C720.22789 (19)0.13925 (10)1.08329 (12)0.0316 (4)
C80.27666 (18)0.29944 (10)1.06552 (11)0.0264 (4)
C8A0.16174 (17)0.31720 (9)0.96983 (11)0.0236 (3)
N90.06635 (15)0.38529 (8)0.97054 (9)0.0262 (3)
C9A0.01999 (17)0.41768 (10)0.88167 (10)0.0240 (3)
H20.19950.54620.74330.033*
H31A0.26570.45410.59250.054*
H31B0.17950.36220.59790.054*
H31C0.09140.45130.59010.054*
H40.07240.27820.73720.028*
H410.07680.15980.66000.033*
H430.15310.24790.90720.037*
H440.34680.14860.89290.041*
H450.51390.03070.79930.043*
H460.57300.06430.66980.049*
H470.42650.06550.55910.051*
H480.23400.03480.57110.044*
H6A0.47830.23060.98060.033*
H6B0.43090.13010.98270.033*
H71A0.45220.21441.22090.049*
H71B0.55810.24821.15620.049*
H71C0.53110.14561.16600.049*
H72A0.19770.15041.14270.047*
H72B0.27300.08071.08650.047*
H72C0.13790.14281.02700.047*
H8A0.22700.30771.11810.032*
H8B0.36020.34281.07530.032*
H90.05940.40821.02550.031*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0290 (7)0.0236 (7)0.0251 (7)0.0037 (6)0.0042 (6)0.0018 (6)
N20.0272 (7)0.0246 (7)0.0268 (7)0.0048 (6)0.0030 (6)0.0038 (6)
C30.0245 (8)0.0269 (8)0.0265 (8)0.0006 (7)0.0070 (7)0.0026 (7)
C310.0367 (10)0.0407 (10)0.0266 (8)0.0049 (8)0.0033 (7)0.0026 (8)
C3A0.0241 (8)0.0238 (8)0.0251 (8)0.0002 (6)0.0063 (6)0.0001 (7)
C40.0263 (8)0.0236 (8)0.0211 (7)0.0001 (6)0.0071 (6)0.0024 (6)
C410.0247 (9)0.0287 (8)0.0283 (8)0.0041 (7)0.0060 (7)0.0029 (7)
C420.0252 (8)0.0216 (8)0.0250 (7)0.0043 (6)0.0018 (6)0.0002 (6)
C430.0341 (10)0.0308 (8)0.0272 (8)0.0019 (7)0.0068 (7)0.0029 (7)
C440.0347 (10)0.0373 (9)0.0311 (9)0.0001 (8)0.0119 (7)0.0027 (8)
C450.0282 (10)0.0323 (9)0.0448 (10)0.0007 (7)0.0046 (8)0.0083 (8)
C460.0312 (10)0.0282 (9)0.0536 (11)0.0042 (8)0.0033 (9)0.0058 (9)
C470.0374 (11)0.0304 (9)0.0509 (11)0.0000 (8)0.0044 (9)0.0091 (9)
C480.0324 (10)0.0334 (9)0.0409 (10)0.0030 (8)0.0038 (8)0.0090 (8)
C48A0.0228 (8)0.0229 (8)0.0320 (8)0.0048 (6)0.0007 (7)0.0011 (7)
C44A0.0266 (9)0.0251 (8)0.0335 (9)0.0053 (7)0.0006 (7)0.0049 (7)
C4A0.0245 (8)0.0201 (7)0.0252 (8)0.0017 (6)0.0067 (6)0.0008 (7)
C50.0250 (8)0.0201 (7)0.0285 (8)0.0043 (6)0.0100 (7)0.0024 (7)
O510.0326 (7)0.0265 (6)0.0344 (6)0.0002 (5)0.0112 (5)0.0097 (5)
C60.0234 (9)0.0242 (8)0.0345 (9)0.0006 (6)0.0077 (7)0.0016 (7)
C70.0244 (9)0.0221 (8)0.0281 (8)0.0016 (6)0.0050 (7)0.0003 (7)
C710.0312 (10)0.0309 (9)0.0331 (9)0.0023 (7)0.0027 (7)0.0012 (8)
C720.0321 (9)0.0271 (8)0.0352 (9)0.0003 (7)0.0086 (7)0.0027 (7)
C80.0301 (9)0.0225 (8)0.0244 (8)0.0014 (6)0.0042 (7)0.0017 (7)
C8A0.0270 (9)0.0184 (7)0.0253 (8)0.0011 (6)0.0070 (7)0.0001 (6)
N90.0340 (8)0.0228 (6)0.0211 (6)0.0068 (6)0.0066 (6)0.0006 (5)
C9A0.0261 (8)0.0207 (7)0.0248 (8)0.0010 (6)0.0063 (6)0.0010 (7)
Geometric parameters (Å, º) top
N1—C9A1.328 (2)C47—C481.361 (2)
N1—N21.366 (2)C47—H470.9500
N2—C31.347 (2)C48—C48A1.405 (2)
N2—H20.8800C48—H480.9500
C3—C3A1.376 (2)C48A—C44A1.422 (2)
C3—C311.488 (2)C4A—C8A1.370 (2)
C31—H31A0.9800C4A—C51.436 (2)
C31—H31B0.9800C5—O511.2374 (18)
C31—H31C0.9800C5—C61.512 (2)
C3A—C9A1.387 (2)C6—C71.526 (2)
C3A—C41.500 (2)C6—H6A0.9900
C4—C4A1.523 (2)C6—H6B0.9900
C4—C421.526 (2)C7—C81.526 (2)
C4—H41.0000C7—C711.527 (2)
C41—C421.357 (2)C7—C721.528 (2)
C41—C48A1.426 (2)C71—H71A0.9800
C41—H410.9500C71—H71B0.9800
C42—C431.417 (2)C71—H71C0.9800
C43—C441.361 (2)C72—H72A0.9800
C43—H430.9500C72—H72B0.9800
C44—C44A1.405 (2)C72—H72C0.9800
C44—H440.9500C8—C8A1.502 (2)
C45—C461.357 (2)C8—H8A0.9900
C45—C44A1.413 (2)C8—H8B0.9900
C45—H450.9500C8A—N91.358 (2)
C46—C471.400 (3)N9—C9A1.390 (2)
C46—H460.9500N9—H90.8800
C9A—N1—N2102.25 (12)C44—C44A—C45122.57 (16)
C3—N2—N1113.42 (12)C44—C44A—C48A118.71 (15)
C3—N2—H2123.3C45—C44A—C48A118.71 (15)
N1—N2—H2123.3C8A—C4A—C5119.39 (14)
N2—C3—C3A106.17 (13)C8A—C4A—C4122.90 (13)
N2—C3—C31122.05 (14)C5—C4A—C4117.69 (13)
C3A—C3—C31131.78 (15)O51—C5—C4A122.06 (14)
C3—C31—H31A109.5O51—C5—C6119.57 (13)
C3—C31—H31B109.5C4A—C5—C6118.35 (13)
H31A—C31—H31B109.5C5—C6—C7113.95 (12)
C3—C31—H31C109.5C5—C6—H6A108.8
H31A—C31—H31C109.5C7—C6—H6A108.8
H31B—C31—H31C109.5C5—C6—H6B108.8
C3—C3A—C9A104.43 (13)C7—C6—H6B108.8
C3—C3A—C4134.37 (14)H6A—C6—H6B107.7
C9A—C3A—C4121.16 (13)C8—C7—C6107.33 (12)
C3A—C4—C4A107.63 (12)C8—C7—C71109.07 (13)
C3A—C4—C42111.26 (12)C6—C7—C71110.06 (13)
C4A—C4—C42111.00 (12)C8—C7—C72110.77 (13)
C3A—C4—H4109.0C6—C7—C72109.95 (13)
C4A—C4—H4109.0C71—C7—C72109.63 (13)
C42—C4—H4109.0C7—C71—H71A109.5
C42—C41—C48A121.92 (15)C7—C71—H71B109.5
C42—C41—H41119.0H71A—C71—H71B109.5
C48A—C41—H41119.0C7—C71—H71C109.5
C41—C42—C43118.81 (15)H71A—C71—H71C109.5
C41—C42—C4121.89 (14)H71B—C71—H71C109.5
C43—C42—C4119.30 (13)C7—C72—H72A109.5
C44—C43—C42121.05 (15)C7—C72—H72B109.5
C44—C43—H43119.5H72A—C72—H72B109.5
C42—C43—H43119.5C7—C72—H72C109.5
C43—C44—C44A121.18 (16)H72A—C72—H72C109.5
C43—C44—H44119.4H72B—C72—H72C109.5
C44A—C44—H44119.4C8A—C8—C7113.64 (13)
C46—C45—C44A120.88 (17)C8A—C8—H8A108.8
C46—C45—H45119.6C7—C8—H8A108.8
C44A—C45—H45119.6C8A—C8—H8B108.8
C45—C46—C47120.05 (16)C7—C8—H8B108.8
C45—C46—H46120.0H8A—C8—H8B107.7
C47—C46—H46120.0N9—C8A—C4A121.87 (14)
C48—C47—C46120.92 (17)N9—C8A—C8114.67 (13)
C48—C47—H47119.5C4A—C8A—C8123.45 (14)
C46—C47—H47119.5C8A—N9—C9A117.82 (12)
C47—C48—C48A120.52 (18)C8A—N9—H9121.1
C47—C48—H48119.7C9A—N9—H9121.1
C48A—C48—H48119.7N1—C9A—C3A113.73 (13)
C48—C48A—C44A118.85 (15)N1—C9A—N9123.43 (13)
C48—C48A—C41122.84 (16)C3A—C9A—N9122.69 (13)
C44A—C48A—C41118.30 (14)
C9A—N1—N2—C30.59 (17)C41—C48A—C44A—C45177.35 (14)
N1—N2—C3—C3A0.99 (18)C3A—C4—C4A—C8A23.76 (19)
N1—N2—C3—C31178.09 (14)C42—C4—C4A—C8A98.22 (16)
N2—C3—C3A—C9A0.93 (17)C3A—C4—C4A—C5158.04 (13)
C31—C3—C3A—C9A178.03 (16)C42—C4—C4A—C579.98 (16)
N2—C3—C3A—C4176.73 (16)C8A—C4A—C5—O51179.87 (14)
C31—C3—C3A—C44.3 (3)C4—C4A—C5—O511.6 (2)
C3—C3A—C4—C4A159.62 (17)C8A—C4A—C5—C62.1 (2)
C9A—C3A—C4—C4A23.03 (19)C4—C4A—C5—C6179.59 (12)
C3—C3A—C4—C4278.6 (2)O51—C5—C6—C7148.75 (14)
C9A—C3A—C4—C4298.79 (17)C4A—C5—C6—C733.22 (19)
C48A—C41—C42—C430.9 (2)C5—C6—C7—C854.59 (16)
C48A—C41—C42—C4178.76 (13)C5—C6—C7—C71173.17 (13)
C3A—C4—C42—C41120.70 (15)C5—C6—C7—C7265.96 (17)
C4A—C4—C42—C41119.46 (16)C6—C7—C8—C8A47.89 (17)
C3A—C4—C42—C4358.94 (18)C71—C7—C8—C8A167.10 (13)
C4A—C4—C42—C4360.90 (18)C72—C7—C8—C8A72.15 (17)
C41—C42—C43—C441.4 (2)C5—C4A—C8A—N9174.52 (13)
C4—C42—C43—C44178.23 (14)C4—C4A—C8A—N97.3 (2)
C42—C43—C44—C44A0.4 (3)C5—C4A—C8A—C84.2 (2)
C44A—C45—C46—C470.6 (2)C4—C4A—C8A—C8173.99 (13)
C45—C46—C47—C482.6 (3)C7—C8—C8A—N9160.58 (13)
C46—C47—C48—C48A2.1 (3)C7—C8—C8A—C4A20.6 (2)
C47—C48—C48A—C44A0.4 (2)C4A—C8A—N9—C9A12.4 (2)
C47—C48—C48A—C41179.23 (15)C8—C8A—N9—C9A166.38 (13)
C42—C41—C48A—C48179.72 (15)N2—N1—C9A—C3A0.06 (17)
C42—C41—C48A—C44A0.6 (2)N2—N1—C9A—N9175.61 (14)
C43—C44—C44A—C45177.80 (15)C3—C3A—C9A—N10.63 (18)
C43—C44—C44A—C48A1.1 (2)C4—C3A—C9A—N1177.41 (13)
C46—C45—C44A—C44179.24 (15)C3—C3A—C9A—N9175.07 (14)
C46—C45—C44A—C48A1.8 (2)C4—C3A—C9A—N96.9 (2)
C48—C48A—C44A—C44178.70 (15)C8A—N9—C9A—N1162.52 (14)
C41—C48A—C44A—C441.6 (2)C8A—N9—C9A—C3A12.8 (2)
C48—C48A—C44A—C452.3 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···O51i0.881.952.810 (2)165
N9—H9···N1ii0.882.052.878 (2)155
Symmetry codes: (i) x, y+1/2, z+3/2; (ii) x, y+1, z+2.

Experimental details

Crystal data
Chemical formulaC23H23N3O
Mr357.44
Crystal system, space groupMonoclinic, P21/c
Temperature (K)150
a, b, c (Å)9.1222 (18), 15.281 (3), 14.346 (3)
β (°) 106.13 (3)
V3)1921.0 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.35 × 0.18 × 0.14
Data collection
DiffractometerKappaCCD
diffractometer
Absorption correctionMulti-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
Tmin, Tmax0.974, 0.989
No. of measured, independent and
observed [I > 2σ(I)] reflections
16205, 4401, 2994
Rint0.062
(sin θ/λ)max1)0.651
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.051, 0.137, 1.03
No. of reflections4401
No. of parameters245
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.23, 0.28

Computer programs: KappaCCD Server Software (Nonius, 1997), DENZO-SMN (Otwinowski & Minor, 1997), DENZO-SMN, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976) and PLATON (Spek, 2000), SHELXL97 and WORDPERFECT macro PRPKAPPA (Ferguson, 1999).

Selected geometric parameters (Å, º) top
N1—C9A1.328 (2)C8A—N91.358 (2)
N1—N21.366 (2)N9—C9A1.390 (2)
N2—C31.347 (2)
C9A—N1—N2102.25 (12)C8A—N9—C9A117.82 (12)
C3—N2—N1113.42 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2···O51i0.881.952.810 (2)165
N9—H9···N1ii0.882.052.878 (2)155
Symmetry codes: (i) x, y+1/2, z+3/2; (ii) x, y+1, z+2.
 

Subscribe to Acta Crystallographica Section E: Crystallographic Communications

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