PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): o1835–o1836.
Published online 2010 June 26. doi:  10.1107/S1600536810024591
PMCID: PMC3007048

8-Methyl-2-[4-(trifluoro­meth­yl)phen­yl]-8H-pyrazolo­[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine methanol disolvate

Abstract

In the title compound, C14H10F3N7·2CH4O, the heterocyclic ring system is essentially planar (r.m.s. deviation = 0.009 Å) and makes a dihedral angle of 6.91 (8)° with the attached benzene ring. In the crystal, the main mol­ecules form centrosymmetric R 2 2(8) dimers via pairs of N—H(...)N hydrogen bonds between the amino groups and pyrimidine N atoms. One of the independent methanol mol­ecules and its inversion equivalent are linked to the dimers via O—H(...)N and N—H(...)O hydrogen bonds, forming R 4 4(16) graph-set motifs. The dimers along with the hydrogen-bonded methanol mol­ecules are stacked along the a axis, with π–π inter­actions between the pyrazole and triazole rings [centroid–centroid distance = 3.4953 (10) Å].

Related literature

For reviews on pyrazolo­[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine adenosine receptor antagonists, see: Baraldi et al. (2006 [triangle]); Cacciari et al. (2007 [triangle]). For the general method used for the synthesis of the title compound, see: Dolzhenko et al. (2009 [triangle]); Cheong et al. (2010 [triangle]). For the crystal structures of related pyrazolo­[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines, see: Ferretti et al. (2006 [triangle]); Mezheritsky et al. (2004 [triangle]); Tyurin et al. (2005 [triangle]); Xiao & Shi (2007 [triangle]). For graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1835-scheme1.jpg

Experimental

Crystal data

  • C14H10F3N7·2CH4O
  • M r = 397.37
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1835-efi1.jpg
  • a = 4.6179 (3) Å
  • b = 17.1149 (10) Å
  • c = 22.7627 (13) Å
  • β = 94.323 (1)°
  • V = 1793.93 (19) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.12 mm−1
  • T = 223 K
  • 0.58 × 0.32 × 0.12 mm

Data collection

  • Bruker SMART APEX CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2001 [triangle]) T min = 0.932, T max = 0.985
  • 12385 measured reflections
  • 4076 independent reflections
  • 3538 reflections with I > 2σ(I)
  • R int = 0.027

Refinement

  • R[F 2 > 2σ(F 2)] = 0.054
  • wR(F 2) = 0.145
  • S = 1.05
  • 4076 reflections
  • 266 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.35 e Å−3
  • Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810024591/ci5111sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810024591/ci5111Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

This work was supported by the National Medical Research Council, Singapore (grant No. NMRC/NIG/0020/2008).

supplementary crystallographic information

Comment

Pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine system has been recognized as an excellent template for the construction of new adenosine receptor antagonists (Baraldi et al., 2006; Cacciari et al., 2007). However, information on the structure of this heterocyclic system is limited (Ferretti et al., 2006; Mezheritsky et al., 2004; Tyurin et al., 2005; Xiao & Shi, 2007). In continuation of our works on the development of new pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine adenosine receptor antagonists (Dolzhenko et al., 2009; Cheong et al., 2010), we report here the molecular and crystal structure of 8-methyl-2-(4-trifluoromethylphenyl)-8H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine.

The compound crystallizes with two methanol solvent molecules. The heterocyclic ring system is essentially planar with an r.m.s. deviation of 0.009 Å. The phenyl ring makes a dihedral angle of 6.91 (8)° with the pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine core. The trifluoromethyl group C atom, C13, is located 0.130 (3) Å above the C7—C12 mean plane.

In the crystal, molecules of 8-methyl-2-(4-trifluoromethylphenyl)-8H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine form centrosymmetric inversion dimers (Fig. 2). The pyrimidine N3 atom is connected with amino group N7—H7B of the pair molecule by intermolecular N···H—N hydrogen bond making R22(8) graph-set motif (Bernstein et al.,1995). Methanol hydroxy group O1S—H1S also links the heterocyclic molecules in the dimer by the N—H···O—H···N hydrogen bond array with amino group N7—H7A and N2 of the pyrazole ring making R44(16) graph-set motif. Another methanol molecule forms the O—H···N hydrogen bond with N6 of the triazole ring. The dimers are stacked along the a axis, with π–π interactions between pyrazole and triazole rings [centroid-to-centroid distance = 3.4953 (10) Å] (Fig. 2).

Experimental

8-Methyl-2-(4-trifluoromethylphenyl)-8H-pyrazolo[4,3-e][1,2,4]triazolo][1,5-c]pyrimidin-5-amine was prepared from 8-methyl-2-(4-trifluoromethylphenyl)-8H-pyrazolo[4,3-e][1,2,4]triazolo][1,5-c]pyrimidine (Dolzhenko et al., 2009) similarly to the described method (Cheong et al., 2010). The detail procedure will be reported elsewhere. The crystals suitable for crystallographic analysis were grown by recrystallization from methanol. m.p. 573 K.

Refinement

All C-bound H atoms were positioned geometrically and included in the refinement in riding-motion approximation [0.94 Å for CH of aromatic systems, 0.97 Å for methyl groups, and 0.83 Å for hydroxyl groups; Uiso(H) = 1.2Ueq(CAr) and Uiso(H) = 1.5Ueq(O,CMe)] while the amino group H atoms were located in a difference map and refined freely.

Figures

Fig. 1.
The asymmetric unit of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2.
Crystal packing of the title compound, viewed along the a axis.

Crystal data

C14H10F3N7·2CH4OF(000) = 824
Mr = 397.37Dx = 1.471 Mg m3
Monoclinic, P21/nMelting point: 573 K
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 4.6179 (3) ÅCell parameters from 4421 reflections
b = 17.1149 (10) Åθ = 2.4–27.2°
c = 22.7627 (13) ŵ = 0.12 mm1
β = 94.323 (1)°T = 223 K
V = 1793.93 (19) Å3Block, colourless
Z = 40.58 × 0.32 × 0.12 mm

Data collection

Bruker SMART APEX CCD diffractometer4076 independent reflections
Radiation source: fine-focus sealed tube3538 reflections with I > 2σ(I)
graphiteRint = 0.027
[var phi] and ω scansθmax = 27.5°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)h = −5→5
Tmin = 0.932, Tmax = 0.985k = −21→22
12385 measured reflectionsl = −23→29

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.054Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.145H atoms treated by a mixture of independent and constrained refinement
S = 1.05w = 1/[σ2(Fo2) + (0.0746P)2 + 0.7421P] where P = (Fo2 + 2Fc2)/3
4076 reflections(Δ/σ)max = 0.001
266 parametersΔρmax = 0.35 e Å3
0 restraintsΔρmin = −0.21 e Å3

Special details

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 > 2σ(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)

xyzUiso*/Ueq
O1S0.5063 (3)0.68580 (11)0.08136 (7)0.0581 (4)
H1S0.45070.68820.04590.087*
C1S0.8079 (5)0.68768 (18)0.08766 (13)0.0684 (7)
H1S10.87350.74150.08870.103*
H1S20.88520.66110.05460.103*
H1S30.87560.66170.12400.103*
C2S0.1594 (6)0.15803 (13)0.27649 (11)0.0581 (6)
H2S10.20280.19170.31030.087*
H2S20.17790.10380.28870.087*
H2S3−0.03740.16780.26020.087*
F11.4952 (3)0.39342 (8)0.43457 (6)0.0616 (4)
F21.2039 (3)0.48312 (8)0.45616 (5)0.0550 (4)
F31.5562 (3)0.50993 (9)0.40469 (6)0.0642 (4)
N1−0.3122 (3)0.23144 (9)0.07561 (7)0.0362 (3)
N2−0.2997 (3)0.29563 (9)0.04026 (7)0.0375 (4)
N3−0.0193 (3)0.41222 (8)0.04749 (6)0.0365 (4)
N40.3019 (3)0.41895 (8)0.13254 (6)0.0296 (3)
N50.5146 (3)0.45421 (8)0.16847 (6)0.0309 (3)
N60.3934 (3)0.33542 (8)0.20487 (6)0.0286 (3)
N70.2815 (4)0.51915 (10)0.06445 (8)0.0461 (4)
H7A0.402 (5)0.5454 (13)0.0863 (10)0.044 (6)*
H7B0.204 (5)0.5402 (14)0.0312 (11)0.052 (6)*
C1−0.1317 (4)0.23497 (10)0.12400 (8)0.0343 (4)
H1−0.10810.19710.15390.041*
C20.0145 (4)0.30557 (9)0.12153 (7)0.0301 (4)
C3−0.0985 (4)0.34097 (10)0.06864 (7)0.0322 (4)
C40.1813 (4)0.45034 (10)0.07964 (7)0.0336 (4)
C50.2331 (4)0.34778 (9)0.15530 (7)0.0276 (3)
C60.5597 (4)0.40191 (9)0.21105 (7)0.0269 (3)
C70.7738 (3)0.41460 (9)0.26155 (7)0.0274 (3)
C80.9154 (4)0.48630 (10)0.26875 (7)0.0326 (4)
H80.87860.52610.24070.039*
C91.1098 (4)0.49892 (10)0.31706 (8)0.0343 (4)
H91.20410.54740.32210.041*
C101.1650 (4)0.43965 (10)0.35808 (7)0.0307 (4)
C111.0299 (4)0.36786 (10)0.35067 (8)0.0343 (4)
H111.07100.32770.37820.041*
C120.8337 (4)0.35550 (10)0.30243 (8)0.0331 (4)
H120.74070.30680.29740.040*
C131.3561 (4)0.45625 (11)0.41268 (8)0.0368 (4)
C14−0.5043 (5)0.16731 (12)0.05670 (10)0.0464 (5)
H14A−0.42410.13960.02450.070*
H14B−0.69400.18790.04360.070*
H14C−0.52290.13170.08940.070*
O2S0.3553 (4)0.17366 (9)0.23347 (8)0.0626 (5)
H2S0.38190.22150.23140.094*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O1S0.0507 (9)0.0792 (12)0.0434 (8)−0.0125 (8)−0.0029 (7)−0.0038 (8)
C1S0.0505 (14)0.0805 (18)0.0727 (17)0.0068 (12)−0.0050 (12)−0.0207 (14)
C2S0.0740 (16)0.0445 (12)0.0554 (13)0.0039 (11)0.0027 (12)0.0023 (10)
F10.0664 (9)0.0601 (8)0.0537 (8)0.0231 (7)−0.0252 (6)−0.0033 (6)
F20.0506 (7)0.0806 (9)0.0333 (6)0.0123 (6)0.0006 (5)−0.0145 (6)
F30.0544 (8)0.0857 (10)0.0502 (7)−0.0294 (7)−0.0117 (6)0.0062 (7)
N10.0395 (8)0.0307 (8)0.0381 (8)−0.0050 (6)0.0010 (6)−0.0035 (6)
N20.0428 (9)0.0336 (8)0.0348 (8)−0.0033 (6)−0.0047 (6)−0.0025 (6)
N30.0491 (9)0.0286 (7)0.0300 (7)−0.0014 (6)−0.0081 (6)0.0023 (6)
N40.0391 (8)0.0237 (7)0.0254 (7)−0.0008 (5)−0.0027 (5)−0.0003 (5)
N50.0385 (8)0.0260 (7)0.0273 (7)−0.0014 (6)−0.0036 (6)−0.0018 (5)
N60.0343 (7)0.0250 (7)0.0264 (7)0.0006 (5)0.0011 (5)0.0003 (5)
N70.0665 (12)0.0316 (8)0.0369 (9)−0.0117 (8)−0.0177 (8)0.0086 (7)
C10.0389 (9)0.0310 (9)0.0332 (9)−0.0026 (7)0.0030 (7)−0.0004 (7)
C20.0350 (9)0.0278 (8)0.0274 (8)0.0001 (6)0.0019 (6)−0.0020 (6)
C30.0382 (9)0.0286 (8)0.0292 (8)0.0018 (7)−0.0014 (7)−0.0029 (6)
C40.0441 (10)0.0277 (8)0.0279 (8)0.0018 (7)−0.0037 (7)0.0018 (6)
C50.0335 (8)0.0232 (7)0.0264 (7)0.0026 (6)0.0040 (6)−0.0013 (6)
C60.0322 (8)0.0234 (7)0.0253 (7)0.0024 (6)0.0031 (6)−0.0008 (6)
C70.0295 (8)0.0277 (8)0.0252 (7)0.0032 (6)0.0029 (6)−0.0008 (6)
C80.0402 (9)0.0272 (8)0.0299 (8)−0.0004 (7)−0.0010 (7)0.0052 (6)
C90.0374 (9)0.0300 (8)0.0349 (9)−0.0041 (7)−0.0011 (7)−0.0002 (7)
C100.0281 (8)0.0361 (9)0.0279 (8)0.0051 (7)0.0022 (6)−0.0005 (7)
C110.0398 (9)0.0312 (9)0.0314 (8)0.0042 (7)−0.0016 (7)0.0068 (7)
C120.0394 (9)0.0252 (8)0.0344 (9)−0.0010 (7)0.0000 (7)0.0021 (6)
C130.0350 (9)0.0426 (10)0.0323 (9)0.0037 (7)0.0002 (7)−0.0005 (7)
C140.0476 (11)0.0386 (10)0.0526 (12)−0.0119 (9)0.0009 (9)−0.0091 (8)
O2S0.0839 (12)0.0294 (7)0.0764 (11)0.0002 (8)0.0186 (9)0.0034 (7)

Geometric parameters (Å, °)

O1S—C1S1.390 (3)N7—C41.321 (2)
O1S—H1S0.83N7—H7A0.85 (2)
C1S—H1S10.97N7—H7B0.89 (2)
C1S—H1S20.97C1—C21.387 (2)
C1S—H1S30.97C1—H10.94
C2S—O2S1.408 (3)C2—C31.412 (2)
C2S—H2S10.97C2—C51.419 (2)
C2S—H2S20.97C6—C71.475 (2)
C2S—H2S30.97C7—C121.388 (2)
F1—C131.330 (2)C7—C81.394 (2)
F2—C131.338 (2)C8—C91.383 (2)
F3—C131.325 (2)C8—H80.94
N1—C11.331 (2)C9—C101.389 (2)
N1—N21.366 (2)C9—H90.94
N1—C141.456 (2)C10—C111.382 (3)
N2—C31.339 (2)C10—C131.496 (2)
N3—C41.310 (2)C11—C121.386 (2)
N3—C31.371 (2)C11—H110.94
N4—N51.3698 (19)C12—H120.94
N4—C51.370 (2)C14—H14A0.97
N4—C41.396 (2)C14—H14B0.97
N5—C61.324 (2)C14—H14C0.97
N6—C51.319 (2)O2S—H2S0.83
N6—C61.374 (2)
C1S—O1S—H1S109.5N6—C5—N4109.56 (14)
O1S—C1S—H1S1109.5N6—C5—C2135.39 (15)
O1S—C1S—H1S2109.5N4—C5—C2115.05 (14)
H1S1—C1S—H1S2109.5N5—C6—N6115.41 (14)
O1S—C1S—H1S3109.5N5—C6—C7122.01 (14)
H1S1—C1S—H1S3109.5N6—C6—C7122.58 (14)
H1S2—C1S—H1S3109.5C12—C7—C8119.65 (15)
O2S—C2S—H2S1109.5C12—C7—C6120.21 (15)
O2S—C2S—H2S2109.5C8—C7—C6120.14 (14)
H2S1—C2S—H2S2109.5C9—C8—C7120.09 (15)
O2S—C2S—H2S3109.5C9—C8—H8120.0
H2S1—C2S—H2S3109.5C7—C8—H8120.0
H2S2—C2S—H2S3109.5C8—C9—C10119.71 (16)
C1—N1—N2113.54 (14)C8—C9—H9120.1
C1—N1—C14127.47 (16)C10—C9—H9120.1
N2—N1—C14118.95 (15)C11—C10—C9120.58 (16)
C3—N2—N1103.90 (14)C11—C10—C13120.16 (16)
C4—N3—C3116.28 (14)C9—C10—C13119.11 (16)
N5—N4—C5110.01 (13)C10—C11—C12119.62 (15)
N5—N4—C4124.55 (14)C10—C11—H11120.2
C5—N4—C4125.41 (14)C12—C11—H11120.2
C6—N5—N4101.84 (13)C11—C12—C7120.34 (16)
C5—N6—C6103.18 (13)C11—C12—H12119.8
C4—N7—H7A123.1 (15)C7—C12—H12119.8
C4—N7—H7B117.2 (15)F3—C13—F1106.84 (16)
H7A—N7—H7B119 (2)F3—C13—F2105.89 (16)
N1—C1—C2106.40 (15)F1—C13—F2105.45 (15)
N1—C1—H1126.8F3—C13—C10113.04 (15)
C2—C1—H1126.8F1—C13—C10113.31 (15)
C1—C2—C3104.97 (15)F2—C13—C10111.71 (14)
C1—C2—C5138.58 (16)N1—C14—H14A109.5
C3—C2—C5116.45 (15)N1—C14—H14B109.5
N2—C3—N3122.67 (15)H14A—C14—H14B109.5
N2—C3—C2111.18 (15)N1—C14—H14C109.5
N3—C3—C2126.15 (15)H14A—C14—H14C109.5
N3—C4—N7122.99 (16)H14B—C14—H14C109.5
N3—C4—N4120.64 (15)C2S—O2S—H2S109.5
N7—C4—N4116.37 (16)
C1—N1—N2—C30.3 (2)C1—C2—C5—N60.6 (4)
C14—N1—N2—C3−177.53 (16)C3—C2—C5—N6−178.44 (18)
C5—N4—N5—C6−0.34 (17)C1—C2—C5—N4−179.5 (2)
C4—N4—N5—C6−178.42 (15)C3—C2—C5—N41.4 (2)
N2—N1—C1—C2−0.4 (2)N4—N5—C6—N60.51 (18)
C14—N1—C1—C2177.22 (17)N4—N5—C6—C7−179.41 (14)
N1—C1—C2—C30.29 (19)C5—N6—C6—N5−0.49 (19)
N1—C1—C2—C5−178.9 (2)C5—N6—C6—C7179.44 (14)
N1—N2—C3—N3179.97 (16)N5—C6—C7—C12−174.11 (16)
N1—N2—C3—C2−0.1 (2)N6—C6—C7—C126.0 (2)
C4—N3—C3—N2−179.75 (17)N5—C6—C7—C86.4 (2)
C4—N3—C3—C20.3 (3)N6—C6—C7—C8−173.47 (15)
C1—C2—C3—N2−0.1 (2)C12—C7—C8—C9−1.4 (3)
C5—C2—C3—N2179.25 (15)C6—C7—C8—C9178.09 (16)
C1—C2—C3—N3179.81 (17)C7—C8—C9—C100.5 (3)
C5—C2—C3—N3−0.8 (3)C8—C9—C10—C110.8 (3)
C3—N3—C4—N7179.18 (18)C8—C9—C10—C13−174.85 (16)
C3—N3—C4—N4−0.5 (3)C9—C10—C11—C12−1.2 (3)
N5—N4—C4—N3179.14 (16)C13—C10—C11—C12174.37 (16)
C5—N4—C4—N31.3 (3)C10—C11—C12—C70.4 (3)
N5—N4—C4—N7−0.6 (3)C8—C7—C12—C110.9 (3)
C5—N4—C4—N7−178.36 (17)C6—C7—C12—C11−178.53 (16)
C6—N6—C5—N40.23 (17)C11—C10—C13—F3154.07 (17)
C6—N6—C5—C2−179.89 (18)C9—C10—C13—F3−30.3 (2)
N5—N4—C5—N60.06 (19)C11—C10—C13—F132.3 (2)
C4—N4—C5—N6178.13 (15)C9—C10—C13—F1−152.04 (17)
N5—N4—C5—C2−179.84 (14)C11—C10—C13—F2−86.6 (2)
C4—N4—C5—C2−1.8 (2)C9—C10—C13—F289.0 (2)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1S—H1S···N2i0.832.052.877 (2)175
O2S—H2S···N60.832.042.853 (2)165
N7—H7A···O1S0.85 (2)2.46 (2)3.050 (2)128 (2)
N7—H7B···N3i0.89 (2)2.09 (3)2.979 (2)179 (2)

Symmetry codes: (i) −x, −y+1, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CI5111).

References

  • Baraldi, P. G., Tabrizi, M. A., Romagnoli, R., El-Kashef, H., Preti, D., Bovero, A., Fruttarolo, F., Gordaliza, M. & Borea, P. A. (2006). Curr. Org. Chem.10, 259–275.
  • Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl.34, 1555–1573.
  • Bruker (2001). SMART and SAINT Bruker AXS GmbH, Karlsruhe, Germany.
  • Cacciari, B., Bolcato, C., Spalluto, G., Klotz, K.-N., Bacilieri, M., Deflorian, F. & Moro, S. (2007). Purinergic Signal.3, 183–193. [PMC free article] [PubMed]
  • Cheong, S. L., Dolzhenko, A., Kachler, S., Paoletta, S., Federico, S., Cacciari, B., Dolzhenko, A., Klotz, K.-N., Moro, S., Spalluto, G. & Pastorin, G. (2010). J. Med. Chem.53, 3361–3375. [PubMed]
  • Dolzhenko, A. V., Pastorin, G., Dolzhenko, A. V. & Chui, W. K. (2009). Tetrahedron Lett.50, 5617–5621.
  • Ferretti, V., Pretto, L., Tabrizi, M. A. & Gilli, P. (2006). Acta Cryst. B62, 634–641. [PubMed]
  • Mezheritsky, V. V., Minkin, V. I., Minyaeva, L. G., Tyurin, R. G., Krasnikov, V. V., Vorobyev, E. V. & Starikova, Z. A. (2004). ARKIVOC, pp. 9–17.
  • Sheldrick, G. M. (2001). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Tyurin, R. V., Vorob’ev, E. V., Minyaeva, L. G., Krasnikov, V. V. & Mezheritskii, V. V. (2005). Russ. J. Org. Chem.41, 916–921.
  • Xiao, L.-X. & Shi, D.-Q. (2007). Acta Cryst. E63, o3613.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography