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In the crystal structure of the title compound, rac-7-oxabicyclo­[2.2.1]heptane-2,3-dicarboxylic acid–2-amino­benzo­thia­zole (1/1), C8H10O5·C7H6N2S, mol­ecules of each component are linked into centrosymmetric dimers by inter­molecular N—H...O hydrogen bonds. These dimers are connected by O—H...O hydrogen bonds into a chain along the b axis. In addition, π–π inter­actions between aromatic heterocycles occur [centroid–centroid distance of 3.4709 Å and inter­planar spacing of 3.4374 Å between symmetry-related benzothia­zole ring systems.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536808015365/kp2168sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536808015365/kp2168Isup2.hkl
Contains datablock I

CCDC reference: 700468

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.004 Å
  • R factor = 0.056
  • wR factor = 0.159
  • Data-to-parameter ratio = 16.0

checkCIF/PLATON results

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Alert level G PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 4 PLAT793_ALERT_4_G Check the Absolute Configuration of C2 ..... S PLAT793_ALERT_4_G Check the Absolute Configuration of C3 ..... R PLAT793_ALERT_4_G Check the Absolute Configuration of C6 ..... S PLAT793_ALERT_4_G Check the Absolute Configuration of C7 ..... R
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 0 ALERT level C = Check and explain 5 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 4 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidin), a traditional Chinese drug, has great anti-cancer activity. In order to prepare compounds with pronounced anti-cancer activity, some derivatives were synthesized (Liu et al., 2002). 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride can react with 2-aminobenzothiazole to form an acylamide acid derivative which has strong anti-cancer activity. However, a crystal suitable for X-ray diffraction was obtained during the synthesis unexpectedly.

The crystal structure of the title compound (I) is characterized by alternating molecules of 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid and 2-aminobenzothiazole, linked by N—H···O and O—H···O hydrogen bonds. The centrosymmetric dimer composed of two 2-aminobenzothiazole and two acids is generated by bifurcated hydrogen bonds of amino group of 2-aminobenzothiazole and the acid component (N1—H1B···O4 and N1—H1B···O5, O3—H3···N2 and N1—H1A···O1). These dimers are connected into a chain by hydrogen bonds O2—H2···O4. Furthermore, there are short distances [centroid separation of 3.4709 Å and interplanar spacing of 3.4374 Å] between the benzothiazole-ring planes and the symmetry-related planes at (-x + 1,-y + 1,-z; -x + 1,-y + 2,-z) of adjacent chains, implying π···π interactions (Fig. 2). In the molecule, the conformation of 7-oxabicyclo[2.2.1]heptane ring is discussed as follows, the six-membered ring adopts a boat conformation and the two oxygen-bearing five-membered heterocycles are in an envelope conformation.

Related literature top

For related literature, see: Liu et al. (2002).

Experimental top

7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride and 2-aminobenzothiazole were dissolved in acetonitrile and the mixture was stirred for 2 h at room temperature. The precipitate has been proved to exhibit anticancer activity. However, colourless crystals of (I) were obtained in the filtrate after several days, unexpectedly.

Refinement top

The structure was solved by direct methods and successive Fourier difference synthesis. The H atoms bonded to C and Natoms were positioned geometrically and refined using a riding model [aromatic C—H 0.93 Å, aliphatic C—H = 0.97 (2) Å and N—H = 0.86 Å Uiso(H) = 1.2Ueq(C)]. The H atoms bonded to O atoms were located in a differenceFourier maps and refined with O—H distance restraints of 0.85 (2) and Uiso(H) = 1.5Ueq(O).

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); 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 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of the molecule of (I) showing the atom-labelling scheme with displacement ellipsoids drawn at the 30% probability.
[Figure 2] Fig. 2. The crystal packing diagram, showing the π···π stacking and hydrogen bonds as dash lines.
rac-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid–2-aminobenzothiazole (1/1) top
Crystal data top
C8H10O5·C7H6N2SZ = 2
Mr = 336.36F(000) = 352
Triclinic, P1Dx = 1.472 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.3082 (1) ÅCell parameters from 4303 reflections
b = 9.0428 (1) Åθ = 2.0–27.4°
c = 11.0438 (2) ŵ = 0.24 mm1
α = 67.1546 (8)°T = 296 K
β = 83.0101 (8)°Block, colourless
γ = 86.9193 (9)°0.43 × 0.27 × 0.16 mm
V = 758.93 (2) Å3
Data collection top
Bruker APEXII area-detector
diffractometer
3416 independent reflections
Radiation source: fine-focus sealed tube2675 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
ω scansθmax = 27.4°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1010
Tmin = 0.92, Tmax = 0.96k = 1111
11829 measured reflectionsl = 1414
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)] = 0.056Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.159H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0773P)2 + 0.3994P]
where P = (Fo2 + 2Fc2)/3
3416 reflections(Δ/σ)max < 0.001
214 parametersΔρmax = 0.67 e Å3
4 restraintsΔρmin = 1.05 e Å3
Crystal data top
C8H10O5·C7H6N2Sγ = 86.9193 (9)°
Mr = 336.36V = 758.93 (2) Å3
Triclinic, P1Z = 2
a = 8.3082 (1) ÅMo Kα radiation
b = 9.0428 (1) ŵ = 0.24 mm1
c = 11.0438 (2) ÅT = 296 K
α = 67.1546 (8)°0.43 × 0.27 × 0.16 mm
β = 83.0101 (8)°
Data collection top
Bruker APEXII area-detector
diffractometer
3416 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
2675 reflections with I > 2σ(I)
Tmin = 0.92, Tmax = 0.96Rint = 0.026
11829 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0564 restraints
wR(F2) = 0.159H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.67 e Å3
3416 reflectionsΔρmin = 1.05 e Å3
214 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
S10.41626 (8)0.33690 (10)0.46435 (8)0.0645 (3)
N10.5173 (3)0.4819 (3)0.2070 (3)0.0640 (6)
H1A0.58270.49570.13690.077*
H1B0.43380.54330.20330.077*
N20.6705 (2)0.2670 (2)0.33434 (19)0.0424 (4)
O10.2197 (2)0.5380 (2)0.00822 (19)0.0616 (5)
O20.28892 (19)1.05947 (19)0.01033 (17)0.0463 (4)
H20.385 (2)1.090 (4)0.025 (3)0.069*
O30.1725 (2)0.7920 (2)0.13815 (17)0.0546 (5)
H30.227 (4)0.770 (4)0.200 (3)0.082*
O40.40832 (17)0.81995 (19)0.06576 (18)0.0489 (4)
O50.17176 (18)0.58165 (18)0.27645 (15)0.0441 (4)
C10.2856 (2)0.9053 (2)0.0535 (2)0.0354 (4)
C20.1220 (2)0.8368 (2)0.1213 (2)0.0342 (4)
H2A0.04240.92400.10930.041*
C30.1319 (3)0.7405 (3)0.2703 (2)0.0405 (5)
H3A0.20940.78400.30790.049*
C40.0397 (3)0.7220 (3)0.3424 (2)0.0486 (6)
H4A0.10050.82190.31160.058*
H4B0.03810.68470.43730.058*
C50.1091 (3)0.5947 (3)0.3034 (3)0.0498 (6)
H5A0.13880.49800.38020.060*
H5B0.20280.63530.25540.060*
C60.0343 (3)0.5643 (3)0.2149 (2)0.0426 (5)
H6A0.03050.46010.20740.051*
C70.0545 (2)0.7055 (3)0.0818 (2)0.0368 (5)
H7A0.05300.73960.05250.044*
C80.1598 (3)0.6691 (3)0.0256 (2)0.0416 (5)
C90.5451 (3)0.3664 (3)0.3202 (3)0.0473 (6)
C100.6687 (3)0.1569 (3)0.4631 (2)0.0460 (5)
C110.7797 (4)0.0351 (3)0.5088 (3)0.0623 (7)
H11A0.86950.02430.45360.075*
C120.7536 (5)0.0717 (4)0.6404 (3)0.0803 (10)
H12A0.82730.15470.67380.096*
C130.6181 (5)0.0553 (4)0.7222 (3)0.0823 (10)
H13A0.60130.12940.80890.099*
C140.5100 (5)0.0671 (5)0.6778 (3)0.0788 (9)
H14A0.42080.07780.73350.095*
C150.5351 (3)0.1745 (3)0.5489 (3)0.0571 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0463 (4)0.0910 (6)0.0724 (5)0.0114 (3)0.0153 (3)0.0539 (4)
N10.0493 (12)0.0656 (14)0.0688 (16)0.0157 (10)0.0021 (11)0.0202 (12)
N20.0411 (9)0.0464 (10)0.0417 (10)0.0012 (8)0.0021 (8)0.0211 (9)
O10.0721 (12)0.0542 (10)0.0538 (11)0.0143 (9)0.0059 (9)0.0212 (9)
O20.0363 (8)0.0413 (8)0.0499 (10)0.0046 (6)0.0004 (7)0.0062 (7)
O30.0684 (11)0.0541 (10)0.0368 (9)0.0106 (8)0.0043 (8)0.0171 (8)
O40.0303 (7)0.0460 (9)0.0630 (11)0.0003 (6)0.0053 (7)0.0159 (8)
O50.0379 (8)0.0474 (9)0.0401 (9)0.0018 (6)0.0035 (6)0.0098 (7)
C10.0315 (9)0.0389 (10)0.0332 (10)0.0018 (8)0.0010 (8)0.0122 (8)
C20.0265 (9)0.0372 (10)0.0373 (11)0.0009 (7)0.0013 (7)0.0141 (9)
C30.0350 (10)0.0506 (12)0.0368 (11)0.0064 (9)0.0012 (8)0.0184 (10)
C40.0433 (12)0.0602 (14)0.0400 (12)0.0075 (10)0.0110 (9)0.0205 (11)
C50.0397 (12)0.0591 (14)0.0452 (13)0.0140 (10)0.0079 (10)0.0162 (11)
C60.0405 (11)0.0420 (11)0.0440 (12)0.0060 (9)0.0013 (9)0.0162 (10)
C70.0296 (9)0.0447 (11)0.0378 (11)0.0007 (8)0.0028 (8)0.0181 (9)
C80.0381 (11)0.0503 (13)0.0394 (12)0.0028 (9)0.0046 (9)0.0210 (10)
C90.0367 (11)0.0551 (13)0.0583 (15)0.0070 (10)0.0065 (10)0.0335 (12)
C100.0556 (14)0.0478 (12)0.0408 (12)0.0131 (10)0.0007 (10)0.0234 (10)
C110.088 (2)0.0553 (15)0.0482 (15)0.0018 (14)0.0140 (14)0.0224 (12)
C120.129 (3)0.0528 (16)0.062 (2)0.0111 (18)0.034 (2)0.0174 (15)
C130.125 (3)0.083 (2)0.0391 (15)0.0536 (16)0.0057 (17)0.0179 (15)
C140.091 (2)0.104 (2)0.0495 (17)0.0510 (15)0.0100 (14)0.0374 (17)
C150.0619 (14)0.0761 (14)0.0439 (14)0.0314 (9)0.0091 (9)0.0351 (11)
Geometric parameters (Å, º) top
S1—C151.734 (3)C4—C51.537 (3)
S1—C91.743 (2)C4—H4A0.9700
N1—C91.318 (4)C4—H4B0.9700
N1—H1A0.8600C5—C61.530 (3)
N1—H1B0.8600C5—H5A0.9700
N2—C91.322 (3)C5—H5B0.9700
N2—C101.382 (3)C6—C71.525 (3)
O1—C81.214 (3)C6—H6A0.9800
O2—C11.295 (3)C7—C81.517 (3)
O2—H20.836 (18)C7—H7A0.9800
O3—C81.303 (3)C10—C111.375 (4)
O3—H30.854 (18)C10—C151.413 (3)
O4—C11.234 (2)C11—C121.396 (4)
O5—C31.434 (3)C11—H11A0.9300
O5—C61.443 (3)C12—C131.395 (6)
C1—C21.508 (3)C12—H12A0.9300
C2—C31.544 (3)C13—C141.361 (5)
C2—C71.565 (3)C13—H13A0.9300
C2—H2A0.9800C14—C151.374 (4)
C3—C41.530 (3)C14—H14A0.9300
C3—H3A0.9800
C15—S1—C989.18 (12)O5—C6—C5102.47 (18)
C9—N1—H1A120.0C7—C6—C5110.16 (19)
C9—N1—H1B120.0O5—C6—H6A113.6
H1A—N1—H1B120.0C7—C6—H6A113.6
C9—N2—C10111.49 (19)C5—C6—H6A113.6
C1—O2—H2109 (2)C8—C7—C6114.11 (18)
C8—O3—H3112 (2)C8—C7—C2115.16 (16)
C3—O5—C696.24 (15)C6—C7—C2101.23 (17)
O4—C1—O2123.04 (18)C8—C7—H7A108.7
O4—C1—C2121.43 (18)C6—C7—H7A108.7
O2—C1—C2115.39 (17)C2—C7—H7A108.7
C1—C2—C3110.23 (17)O1—C8—O3124.6 (2)
C1—C2—C7116.64 (16)O1—C8—C7123.1 (2)
C3—C2—C7100.43 (16)O3—C8—C7112.29 (18)
C1—C2—H2A109.7N1—C9—N2123.7 (2)
C3—C2—H2A109.7N1—C9—S1121.07 (18)
C7—C2—H2A109.7N2—C9—S1115.2 (2)
O5—C3—C4103.13 (17)C11—C10—N2125.6 (2)
O5—C3—C2102.91 (16)C11—C10—C15120.4 (2)
C4—C3—C2108.53 (18)N2—C10—C15114.0 (2)
O5—C3—H3A113.7C10—C11—C12118.0 (3)
C4—C3—H3A113.7C10—C11—H11A121.0
C2—C3—H3A113.7C12—C11—H11A121.0
C3—C4—C5101.17 (18)C11—C12—C13120.6 (3)
C3—C4—H4A111.5C11—C12—H12A119.7
C5—C4—H4A111.5C13—C12—H12A119.7
C3—C4—H4B111.5C14—C13—C12121.3 (3)
C5—C4—H4B111.5C14—C13—H13A119.3
H4A—C4—H4B109.4C12—C13—H13A119.3
C6—C5—C4101.63 (17)C13—C14—C15118.7 (3)
C6—C5—H5A111.4C13—C14—H14A120.6
C4—C5—H5A111.4C15—C14—H14A120.6
C6—C5—H5B111.4C14—C15—C10120.9 (3)
C4—C5—H5B111.4C14—C15—S1128.9 (3)
H5A—C5—H5B109.3C10—C15—S1110.1 (2)
O5—C6—C7102.38 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.862.132.953 (3)161
N1—H1B···O50.862.293.061 (3)150
N1—H1B···O40.862.382.991 (3)128
O2—H2···O4ii0.84 (2)1.87 (2)2.700 (2)174 (3)
O3—H3···N2i0.85 (2)1.76 (2)2.611 (2)176 (4)
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y+2, z.

Experimental details

Crystal data
Chemical formulaC8H10O5·C7H6N2S
Mr336.36
Crystal system, space groupTriclinic, P1
Temperature (K)296
a, b, c (Å)8.3082 (1), 9.0428 (1), 11.0438 (2)
α, β, γ (°)67.1546 (8), 83.0101 (8), 86.9193 (9)
V3)758.93 (2)
Z2
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.43 × 0.27 × 0.16
Data collection
DiffractometerBruker APEXII area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.92, 0.96
No. of measured, independent and
observed [I > 2σ(I)] reflections
11829, 3416, 2675
Rint0.026
(sin θ/λ)max1)0.648
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.159, 1.07
No. of reflections3416
No. of parameters214
No. of restraints4
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.67, 1.05

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O1i0.862.132.953 (3)161.0
N1—H1B···O50.862.293.061 (3)150.1
N1—H1B···O40.862.382.991 (3)128.0
O2—H2···O4ii0.836 (18)1.868 (18)2.700 (2)174 (3)
O3—H3···N2i0.854 (18)1.758 (19)2.611 (2)176 (4)
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y+2, z.
 

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