rac-7-Oxabicyclo­[2.2.1]heptane-2,3-dicarboxylic acid–2-amino-1,3,4-thia­diazole–water (1/1/1)

Na Wang; Qiu-Yue Lin; Yan-Jun Wang

doi:10.1107/S1600536809021825

. 2009 Jun 17;65(Pt 7):o1590. doi: 10.1107/S1600536809021825

rac-7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid–2-amino-1,3,4-thiadiazole–water (1/1/1)

Na Wang ^a, Qiu-Yue Lin ^a,^*, Yan-Jun Wang ^a

PMCID: PMC2969213 PMID: 21582865

Abstract

The title compound, C₈H₁₀O₅·C₂H₃N₃S·H₂O, was synthesized by the reaction of 2-amino-1,3,4-thiadiazole with norcantharidin. The crystal structure is stabilized by N—H⋯O, N—H⋯N, O—H⋯O and O—H⋯N hydrogen bonds. In addition, weak π–π interactions are observed between symmetry-related thiadiazole ring systems [centroid–centroid distance = 3.9110 (3) Å, interplanar spacing = 3.4845 Å].

Related literature

7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidin) is a lower toxicity anticancer drug, see: Shimi & Zaki (1982 ▶).

Experimental

Crystal data

C₈H₁₀O₅·C₂H₃N₃S·H₂O
M _r = 305.31
Monoclinic,
a = 5.7678 (5) Å
b = 18.4267 (15) Å
c = 12.7546 (11) Å
β = 101.336 (6)°
V = 1329.1 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.27 mm⁻¹
T = 296 K
0.30 × 0.16 × 0.09 mm

Data collection

Bruker APEXII area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.949, T _max = 0.977
10820 measured reflections
2995 independent reflections
2026 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.133
S = 1.05
2995 reflections
187 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809021825/at2800sup1.cif

e-65-o1590-sup1.cif^{(19KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809021825/at2800Isup2.hkl

e-65-o1590-Isup2.hkl^{(189KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O4ⁱ	0.86	2.11	2.930 (3)	160
N1—H1C⋯N3ⁱⁱ	0.86	2.15	2.994 (3)	166
N1—H1C⋯N2ⁱⁱ	0.86	2.69	3.519 (3)	161
O2—H2A⋯O1Wⁱⁱⁱ	0.82	1.81	2.626 (2)	176
O5—H5B⋯N2^iv	0.82	1.85	2.664 (2)	172
O1W—H1WA⋯O3^v	0.859 (17)	1.910 (17)	2.766 (2)	175 (3)
O1W—H1WB⋯O4^vi	0.819 (17)	2.51 (3)	3.151 (3)	137 (3)
O1W—H1WB⋯O1^vi	0.819 (17)	2.55 (3)	3.061 (3)	122 (3)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

The authors thank the Natural Science Foundation of Zhejiang Province, China (grant No. Y407301) for financial support.

supplementary crystallographic information

Comment

7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidin) derived from cantharidin is a lower toxicity anticancer drug (Shimi & Zaki, 1982). The title compound was synthesized by the reaction of 2-amino-1,3,4-thiadiazole with 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidin). In this paper, we reports its structure.

X-ray crystallography measurement confirmed the molecular structure and the atom connectivity for the title compound (Fig. 1). The crystal structure is stabilized by N—H···O, N—H···N, O—H···O and O—H···N hydrogen bonds (Table 1). Further, weak π–π interactions are observed between symmetry related thiadiazole ring systems [centroid-centroid distance of 3.9110 (3)Å and interplanar spacing of 3.4845 Å].

Experimental

7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride and 2-amino-1,3,4-thiadiazole were dissolved in tetrahydrofuran and the mixture was stirred for 6 h at room temperature. The clear solution was left undisturbed for days to give colourless crystals of the compound.