Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807035842/gg2028sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807035842/gg2028Isup2.hkl |
CCDC reference: 657847
Doxofylline and acrylic acid in 1:1 molar ratio were mixed together in suffient ethanol and heated to afford a clear solution. Crystals of (I) were formed by gradual evaporation of ethanol over a period of one week at 293 K.
All H atoms were placed in calculated positions and allowed to ride on their parent atoms at distances of 0.82 (O—H), 0.93 (unsaturated), 0.96 (methyl), 0.97 (methylene) and 0.98 Å (methine), with Uiso(H) = 1.2 or 1.5 Ueq(C) and Ueq(O).
Doxofylline [7-(1,3-dioxolan-2-ylmethyl)-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione] is a therapeutic agent with anti-asthmatic (Franzone et al., 1989), antiinflammatory activities (Zhao et al., 2001) and a bronchodilating effect on smooth muscle (Franzone et al., 1981; Villani et al., 1997). These studies provide important reference points for futher research into doxofylline. Herein we present the structure of the title compound, (I), a 1:1 complex of doxofylline:acrylic acid.
As shown in Fig. 1, compound (I) is comprised of a doxofylline and acrylic acid molecule. The atoms of acrylic acid molecule are almost coplanar. The angle between the plane of acrylic acid and the plane of the purine ring is 8.2°. The doxofylline molecule in (I) adopts a different conformation from that observed in doxofylline (Chen, Tu, et al., 2007; Chen, Tu & Jin, 2007). In (I), a disordered carbon atom in the dioxolane ring is observed and modelled with site occupancies of 0.759 (17):0.241 (17) for the major and minor sites, respectively.
The geometrical arrangement in the crystal is characterized by formation of the parallel purine rings (Fig. 2). While the O5—H5···N4 hydrogen bond plays an important role in forming the complex, the hydrogen bonds of C5—H5A···O6 and C6—H6A···O1 (Table 2) play roles in dimer formation (forming dimers of (I)) and ultimately a three-dimensional structure is seen via interlocking dioxalane groups and π···π stacking interactions
For related literature, see: Chen, Tu & Jin (2007); Chen, Tu et al. (2007); Franzone et al. (1981, 1989); Villani et al. (1997); Zhao & Li (2001).
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL(Bruker, 2000); software used to prepare material for publication: SHELXL97.
Fig. 1. An ORTEP diagram of the 1:1 complex of (I) with atoms displayed with 30% probability displacement ellipsoids. |
C11H14N4O4·C3H4O2 | V = 788.70 (15) Å3 |
Mr = 338.32 | Z = 2 |
Triclinic, P1 | F(000) = 356 |
Hall symbol: -P 1 | Dx = 1.425 Mg m−3 |
a = 5.5365 (6) Å | Melting point: 428 K |
b = 10.1199 (12) Å | Mo Kα radiation, λ = 0.71073 Å |
c = 14.2916 (16) Å | µ = 0.11 mm−1 |
α = 87.182 (2)° | T = 273 K |
β = 88.023 (2)° | Block, colourless |
γ = 80.578 (2)° | 0.32 × 0.23 × 0.20 mm |
Bruker APEX area-detector diffractometer | 2785 independent reflections |
Radiation source: fine-focus sealed tube | 2445 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.014 |
φ and ω scans | θmax = 25.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −4→6 |
Tmin = 0.969, Tmax = 0.978 | k = −12→12 |
4155 measured reflections | l = −16→16 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.069 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.169 | H-atom parameters constrained |
S = 1.15 | w = 1/[σ2(Fo2) + (0.0731P)2 + 0.3726P] where P = (Fo2 + 2Fc2)/3 |
2785 reflections | (Δ/σ)max < 0.001 |
229 parameters | Δρmax = 0.23 e Å−3 |
4 restraints | Δρmin = −0.20 e Å−3 |
C11H14N4O4·C3H4O2 | γ = 80.578 (2)° |
Mr = 338.32 | V = 788.70 (15) Å3 |
Triclinic, P1 | Z = 2 |
a = 5.5365 (6) Å | Mo Kα radiation |
b = 10.1199 (12) Å | µ = 0.11 mm−1 |
c = 14.2916 (16) Å | T = 273 K |
α = 87.182 (2)° | 0.32 × 0.23 × 0.20 mm |
β = 88.023 (2)° |
Bruker APEX area-detector diffractometer | 2785 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 2445 reflections with I > 2σ(I) |
Tmin = 0.969, Tmax = 0.978 | Rint = 0.014 |
4155 measured reflections |
R[F2 > 2σ(F2)] = 0.069 | 4 restraints |
wR(F2) = 0.169 | H-atom parameters constrained |
S = 1.15 | Δρmax = 0.23 e Å−3 |
2785 reflections | Δρmin = −0.20 e Å−3 |
229 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | −0.1246 (4) | 1.0444 (2) | 0.77706 (15) | 0.0621 (6) | |
O2 | −0.1415 (5) | 0.8294 (3) | 0.50445 (15) | 0.0777 (7) | |
O3 | 0.0059 (3) | 0.82622 (19) | 0.96331 (14) | 0.0521 (5) | |
O4 | 0.3894 (3) | 0.7265 (2) | 0.99833 (15) | 0.0604 (6) | |
O5 | 0.8511 (4) | 0.4874 (3) | 0.66161 (16) | 0.0743 (7) | |
H5 | 0.7459 | 0.5509 | 0.6752 | 0.111* | |
O6 | 1.0023 (4) | 0.5298 (3) | 0.79567 (17) | 0.0796 (7) | |
N1 | −0.1292 (4) | 0.9348 (2) | 0.64116 (16) | 0.0507 (6) | |
N2 | 0.1766 (5) | 0.7543 (2) | 0.59918 (15) | 0.0526 (6) | |
N3 | 0.3591 (4) | 0.8519 (2) | 0.81369 (15) | 0.0450 (5) | |
N4 | 0.5041 (4) | 0.6996 (2) | 0.71012 (16) | 0.0518 (6) | |
C1 | −0.0279 (5) | 0.9562 (3) | 0.72678 (19) | 0.0451 (6) | |
C2 | −0.0371 (6) | 0.8378 (3) | 0.5766 (2) | 0.0564 (8) | |
C3 | 0.2886 (5) | 0.7699 (3) | 0.68106 (18) | 0.0447 (6) | |
C4 | 0.1916 (5) | 0.8642 (3) | 0.74297 (18) | 0.0427 (6) | |
C5 | 0.5383 (5) | 0.7531 (3) | 0.7905 (2) | 0.0513 (7) | |
H5A | 0.6741 | 0.7245 | 0.8272 | 0.062* | |
C6 | 0.3419 (5) | 0.9260 (3) | 0.89930 (19) | 0.0497 (7) | |
H6A | 0.2372 | 1.0118 | 0.8889 | 0.060* | |
H6B | 0.5034 | 0.9433 | 0.9139 | 0.060* | |
C7 | 0.2412 (5) | 0.8517 (3) | 0.98124 (19) | 0.0485 (7) | |
H7 | 0.2343 | 0.9049 | 1.0370 | 0.058* | |
C8 | −0.0116 (6) | 0.7026 (3) | 1.0123 (3) | 0.0731 (10) | |
H8A | −0.1271 | 0.6565 | 0.9827 | 0.088* | |
H8B | −0.0649 | 0.7172 | 1.0768 | 0.088* | |
C9 | 0.2359 (7) | 0.6245 (5) | 1.0077 (7) | 0.065 (2) | 0.759 (17) |
H9A | 0.2707 | 0.5688 | 1.0644 | 0.078* | 0.759 (17) |
H9B | 0.2571 | 0.5681 | 0.9542 | 0.078* | 0.759 (17) |
C9' | 0.2275 (17) | 0.664 (2) | 1.0606 (12) | 0.067 (5) | 0.241 (17) |
H9'1 | 0.2199 | 0.7000 | 1.1226 | 0.080* | 0.241 (17) |
H9'2 | 0.2765 | 0.5678 | 1.0656 | 0.080* | 0.241 (17) |
C10 | 1.3987 (7) | 0.3237 (4) | 0.7628 (3) | 0.0873 (12) | |
H10A | 1.4119 | 0.3776 | 0.8127 | 0.105* | |
H10B | 1.5211 | 0.2515 | 0.7509 | 0.105* | |
C11 | 1.2085 (6) | 0.3495 (3) | 0.7096 (2) | 0.0695 (9) | |
H11 | 1.1959 | 0.2954 | 0.6599 | 0.083* | |
C12 | 1.0133 (5) | 0.4639 (3) | 0.7279 (2) | 0.0539 (7) | |
C13 | 0.2871 (7) | 0.6508 (3) | 0.5350 (2) | 0.0693 (9) | |
H13A | 0.4423 | 0.6706 | 0.5115 | 0.104* | |
H13B | 0.1805 | 0.6493 | 0.4836 | 0.104* | |
H13C | 0.3105 | 0.5649 | 0.5679 | 0.104* | |
C14 | −0.3516 (6) | 1.0260 (4) | 0.6145 (2) | 0.0715 (9) | |
H14A | −0.3993 | 1.0880 | 0.6631 | 0.107* | |
H14B | −0.4807 | 0.9754 | 0.6059 | 0.107* | |
H14C | −0.3206 | 1.0746 | 0.5572 | 0.107* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0637 (13) | 0.0575 (12) | 0.0594 (13) | 0.0109 (10) | −0.0033 (10) | −0.0151 (10) |
O2 | 0.0814 (16) | 0.0993 (18) | 0.0498 (13) | 0.0009 (14) | −0.0222 (12) | −0.0146 (12) |
O3 | 0.0338 (10) | 0.0583 (12) | 0.0626 (13) | −0.0032 (8) | −0.0045 (9) | −0.0001 (10) |
O4 | 0.0349 (10) | 0.0802 (15) | 0.0636 (13) | −0.0032 (10) | −0.0104 (9) | 0.0089 (11) |
O5 | 0.0660 (15) | 0.0874 (18) | 0.0625 (14) | 0.0172 (12) | −0.0082 (12) | −0.0293 (12) |
O6 | 0.0764 (16) | 0.0865 (17) | 0.0690 (15) | 0.0183 (13) | −0.0147 (12) | −0.0305 (13) |
N1 | 0.0496 (14) | 0.0566 (14) | 0.0439 (13) | −0.0013 (11) | −0.0066 (11) | −0.0020 (11) |
N2 | 0.0608 (15) | 0.0570 (14) | 0.0385 (13) | −0.0017 (12) | −0.0028 (11) | −0.0113 (11) |
N3 | 0.0425 (12) | 0.0520 (13) | 0.0405 (12) | −0.0055 (10) | 0.0006 (10) | −0.0093 (10) |
N4 | 0.0501 (14) | 0.0581 (14) | 0.0434 (13) | 0.0038 (11) | 0.0018 (10) | −0.0085 (11) |
C1 | 0.0459 (15) | 0.0450 (15) | 0.0434 (15) | −0.0053 (12) | 0.0043 (12) | −0.0025 (12) |
C2 | 0.0603 (19) | 0.0653 (19) | 0.0436 (17) | −0.0085 (15) | −0.0065 (14) | −0.0045 (14) |
C3 | 0.0471 (15) | 0.0488 (15) | 0.0373 (14) | −0.0042 (12) | 0.0004 (11) | −0.0047 (11) |
C4 | 0.0437 (14) | 0.0464 (15) | 0.0384 (14) | −0.0083 (12) | 0.0007 (11) | −0.0046 (11) |
C5 | 0.0437 (15) | 0.0624 (18) | 0.0449 (16) | 0.0017 (13) | −0.0013 (12) | −0.0060 (13) |
C6 | 0.0495 (16) | 0.0547 (16) | 0.0479 (16) | −0.0133 (13) | −0.0001 (13) | −0.0172 (13) |
C7 | 0.0420 (15) | 0.0624 (17) | 0.0432 (15) | −0.0100 (13) | −0.0039 (12) | −0.0161 (13) |
C8 | 0.0477 (18) | 0.073 (2) | 0.099 (3) | −0.0149 (16) | −0.0117 (18) | 0.020 (2) |
C9 | 0.047 (2) | 0.060 (3) | 0.088 (5) | −0.007 (2) | −0.012 (2) | 0.006 (3) |
C9' | 0.073 (10) | 0.064 (10) | 0.059 (11) | −0.001 (7) | 0.000 (8) | −0.009 (8) |
C10 | 0.074 (2) | 0.090 (3) | 0.088 (3) | 0.022 (2) | −0.007 (2) | −0.023 (2) |
C11 | 0.070 (2) | 0.066 (2) | 0.067 (2) | 0.0065 (17) | 0.0001 (18) | −0.0171 (17) |
C12 | 0.0528 (17) | 0.0547 (17) | 0.0524 (17) | −0.0025 (14) | 0.0050 (14) | −0.0095 (14) |
C13 | 0.090 (2) | 0.069 (2) | 0.0462 (18) | 0.0015 (18) | 0.0000 (16) | −0.0195 (15) |
C14 | 0.063 (2) | 0.081 (2) | 0.063 (2) | 0.0099 (17) | −0.0122 (16) | 0.0023 (17) |
O1—C1 | 1.216 (3) | C6—C7 | 1.501 (4) |
O2—C2 | 1.213 (4) | C6—H6A | 0.9700 |
O3—C7 | 1.403 (3) | C6—H6B | 0.9700 |
O3—C8 | 1.418 (4) | C7—H7 | 0.9800 |
O4—C7 | 1.407 (3) | C8—C9 | 1.467 (5) |
O4—C9' | 1.437 (9) | C8—C9' | 1.499 (9) |
O4—C9 | 1.440 (5) | C8—H8A | 0.9700 |
O5—C12 | 1.315 (4) | C8—H8B | 0.9700 |
O5—H5 | 0.8200 | C9—H9A | 0.9700 |
O6—C12 | 1.197 (4) | C9—H9B | 0.9700 |
N1—C2 | 1.403 (4) | C9'—H9'1 | 0.9700 |
N1—C1 | 1.404 (3) | C9'—H9'2 | 0.9700 |
N1—C14 | 1.462 (4) | C10—C11 | 1.304 (5) |
N2—C3 | 1.371 (3) | C10—H10A | 0.9300 |
N2—C2 | 1.375 (4) | C10—H10B | 0.9300 |
N2—C13 | 1.469 (4) | C11—C12 | 1.476 (4) |
N3—C5 | 1.334 (4) | C11—H11 | 0.9300 |
N3—C4 | 1.383 (3) | C13—H13A | 0.9600 |
N3—C6 | 1.458 (3) | C13—H13B | 0.9600 |
N4—C5 | 1.327 (4) | C13—H13C | 0.9600 |
N4—C3 | 1.353 (4) | C14—H14A | 0.9600 |
C1—C4 | 1.424 (4) | C14—H14B | 0.9600 |
C3—C4 | 1.365 (4) | C14—H14C | 0.9600 |
C5—H5A | 0.9300 | ||
C7—O3—C8 | 105.0 (2) | O3—C8—C9' | 104.9 (6) |
C7—O4—C9' | 99.5 (7) | O3—C8—H8A | 110.7 |
C7—O4—C9 | 108.9 (2) | C9—C8—H8A | 110.7 |
C12—O5—H5 | 109.5 | C9'—C8—H8A | 136.8 |
C2—N1—C1 | 127.3 (2) | O3—C8—H8B | 110.7 |
C2—N1—C14 | 116.0 (2) | C9—C8—H8B | 110.7 |
C1—N1—C14 | 116.7 (2) | C9'—C8—H8B | 79.6 |
C3—N2—C2 | 119.6 (2) | H8A—C8—H8B | 108.8 |
C3—N2—C13 | 120.2 (3) | O4—C9—C8 | 102.9 (3) |
C2—N2—C13 | 120.2 (2) | O4—C9—H9A | 111.2 |
C5—N3—C4 | 106.2 (2) | C8—C9—H9A | 111.2 |
C5—N3—C6 | 125.9 (2) | O4—C9—H9B | 111.2 |
C4—N3—C6 | 127.8 (2) | C8—C9—H9B | 111.2 |
C5—N4—C3 | 103.6 (2) | H9A—C9—H9B | 109.1 |
O1—C1—N1 | 121.4 (3) | O4—C9'—C8 | 101.4 (6) |
O1—C1—C4 | 127.5 (3) | O4—C9'—H9'1 | 111.5 |
N1—C1—C4 | 111.2 (2) | C8—C9'—H9'1 | 111.5 |
O2—C2—N2 | 122.2 (3) | O4—C9'—H9'2 | 111.5 |
O2—C2—N1 | 121.2 (3) | C8—C9'—H9'2 | 111.5 |
N2—C2—N1 | 116.7 (2) | H9'1—C9'—H9'2 | 109.3 |
N4—C3—C4 | 111.8 (2) | C11—C10—H10A | 120.0 |
N4—C3—N2 | 126.0 (2) | C11—C10—H10B | 120.0 |
C4—C3—N2 | 122.2 (2) | H10A—C10—H10B | 120.0 |
C3—C4—N3 | 104.9 (2) | C10—C11—C12 | 120.4 (3) |
C3—C4—C1 | 123.1 (2) | C10—C11—H11 | 119.8 |
N3—C4—C1 | 131.8 (2) | C12—C11—H11 | 119.8 |
N4—C5—N3 | 113.5 (3) | O6—C12—O5 | 122.8 (3) |
N4—C5—H5A | 123.3 | O6—C12—C11 | 124.1 (3) |
N3—C5—H5A | 123.3 | O5—C12—C11 | 113.1 (3) |
N3—C6—C7 | 112.4 (2) | N2—C13—H13A | 109.5 |
N3—C6—H6A | 109.1 | N2—C13—H13B | 109.5 |
C7—C6—H6A | 109.1 | H13A—C13—H13B | 109.5 |
N3—C6—H6B | 109.1 | N2—C13—H13C | 109.5 |
C7—C6—H6B | 109.1 | H13A—C13—H13C | 109.5 |
H6A—C6—H6B | 107.9 | H13B—C13—H13C | 109.5 |
O3—C7—O4 | 106.9 (2) | N1—C14—H14A | 109.5 |
O3—C7—C6 | 110.9 (2) | N1—C14—H14B | 109.5 |
O4—C7—C6 | 110.6 (2) | H14A—C14—H14B | 109.5 |
O3—C7—H7 | 109.5 | N1—C14—H14C | 109.5 |
O4—C7—H7 | 109.5 | H14A—C14—H14C | 109.5 |
C6—C7—H7 | 109.5 | H14B—C14—H14C | 109.5 |
O3—C8—C9 | 105.4 (3) | ||
C2—N1—C1—O1 | 179.7 (3) | O1—C1—C4—C3 | −178.6 (3) |
C14—N1—C1—O1 | 1.7 (4) | N1—C1—C4—C3 | 1.0 (4) |
C2—N1—C1—C4 | 0.0 (4) | O1—C1—C4—N3 | −3.8 (5) |
C14—N1—C1—C4 | −178.0 (3) | N1—C1—C4—N3 | 175.9 (3) |
C3—N2—C2—O2 | 179.0 (3) | C3—N4—C5—N3 | 0.0 (3) |
C13—N2—C2—O2 | 0.3 (5) | C4—N3—C5—N4 | 0.4 (3) |
C3—N2—C2—N1 | −0.7 (4) | C6—N3—C5—N4 | 177.6 (2) |
C13—N2—C2—N1 | −179.4 (3) | C5—N3—C6—C7 | −81.2 (3) |
C1—N1—C2—O2 | −179.8 (3) | C4—N3—C6—C7 | 95.5 (3) |
C14—N1—C2—O2 | −1.9 (4) | C8—O3—C7—O4 | 27.3 (3) |
C1—N1—C2—N2 | −0.1 (4) | C8—O3—C7—C6 | 147.9 (3) |
C14—N1—C2—N2 | 177.8 (3) | C9'—O4—C7—O3 | −45.4 (9) |
C5—N4—C3—C4 | −0.5 (3) | C9—O4—C7—O3 | −10.3 (5) |
C5—N4—C3—N2 | 178.2 (3) | C9'—O4—C7—C6 | −166.3 (9) |
C2—N2—C3—N4 | −176.8 (3) | C9—O4—C7—C6 | −131.2 (5) |
C13—N2—C3—N4 | 1.9 (4) | N3—C6—C7—O3 | −59.6 (3) |
C2—N2—C3—C4 | 1.8 (4) | N3—C6—C7—O4 | 58.9 (3) |
C13—N2—C3—C4 | −179.6 (3) | C7—O3—C8—C9 | −33.7 (5) |
N4—C3—C4—N3 | 0.7 (3) | C7—O3—C8—C9' | 1.7 (10) |
N2—C3—C4—N3 | −178.0 (2) | C7—O4—C9—C8 | −10.1 (7) |
N4—C3—C4—C1 | 176.7 (2) | O3—C8—C9—O4 | 26.7 (6) |
N2—C3—C4—C1 | −2.0 (4) | C7—O4—C9'—C8 | 43.9 (14) |
C5—N3—C4—C3 | −0.6 (3) | O3—C8—C9'—O4 | −28.8 (15) |
C6—N3—C4—C3 | −177.8 (2) | C10—C11—C12—O6 | −8.0 (6) |
C5—N3—C4—C1 | −176.2 (3) | C10—C11—C12—O5 | 171.6 (4) |
C6—N3—C4—C1 | 6.6 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5···N4 | 0.82 | 1.92 | 2.736 (3) | 178 |
C5—H5A···O6 | 0.93 | 2.50 | 3.131 (4) | 125 |
C6—H6A···O1 | 0.97 | 2.58 | 3.202 (3) | 122 |
C13—H13B···O5i | 0.96 | 2.58 | 3.365 (4) | 140 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C11H14N4O4·C3H4O2 |
Mr | 338.32 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 273 |
a, b, c (Å) | 5.5365 (6), 10.1199 (12), 14.2916 (16) |
α, β, γ (°) | 87.182 (2), 88.023 (2), 80.578 (2) |
V (Å3) | 788.70 (15) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.32 × 0.23 × 0.20 |
Data collection | |
Diffractometer | Bruker APEX area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.969, 0.978 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4155, 2785, 2445 |
Rint | 0.014 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.069, 0.169, 1.15 |
No. of reflections | 2785 |
No. of parameters | 229 |
No. of restraints | 4 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.23, −0.20 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL(Bruker, 2000), SHELXL97.
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5···N4 | 0.82 | 1.92 | 2.736 (3) | 178 |
C5—H5A···O6 | 0.93 | 2.50 | 3.131 (4) | 125 |
C6—H6A···O1 | 0.97 | 2.58 | 3.202 (3) | 122 |
C13—H13B···O5i | 0.96 | 2.58 | 3.365 (4) | 140 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Doxofylline [7-(1,3-dioxolan-2-ylmethyl)-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione] is a therapeutic agent with anti-asthmatic (Franzone et al., 1989), antiinflammatory activities (Zhao et al., 2001) and a bronchodilating effect on smooth muscle (Franzone et al., 1981; Villani et al., 1997). These studies provide important reference points for futher research into doxofylline. Herein we present the structure of the title compound, (I), a 1:1 complex of doxofylline:acrylic acid.
As shown in Fig. 1, compound (I) is comprised of a doxofylline and acrylic acid molecule. The atoms of acrylic acid molecule are almost coplanar. The angle between the plane of acrylic acid and the plane of the purine ring is 8.2°. The doxofylline molecule in (I) adopts a different conformation from that observed in doxofylline (Chen, Tu, et al., 2007; Chen, Tu & Jin, 2007). In (I), a disordered carbon atom in the dioxolane ring is observed and modelled with site occupancies of 0.759 (17):0.241 (17) for the major and minor sites, respectively.
The geometrical arrangement in the crystal is characterized by formation of the parallel purine rings (Fig. 2). While the O5—H5···N4 hydrogen bond plays an important role in forming the complex, the hydrogen bonds of C5—H5A···O6 and C6—H6A···O1 (Table 2) play roles in dimer formation (forming dimers of (I)) and ultimately a three-dimensional structure is seen via interlocking dioxalane groups and π···π stacking interactions