7-(1,3-Dioxolan-2-ylmethyl)-1,3-di­methyl-2,6-dioxo-2,3,6,7-tetra­hydro-1H-purin-9-ium tetra­chloridoferrate(III)

Ping Ping Wang; Jiang Gong; Shi-Feng Ni

doi:10.1107/S1600536810034720

. 2010 Sep 11;66(Pt 10):m1247. doi: 10.1107/S1600536810034720

7-(1,3-Dioxolan-2-ylmethyl)-1,3-dimethyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-9-ium tetrachloridoferrate(III)

Ping Ping Wang ^a, Jiang Gong ^b,^c, Shi-Feng Ni ^c,^*

PMCID: PMC2983145 PMID: 21587397

Abstract

The asymmetric unit of the title compound, (C₁₁H₁₅N₄O₄)[FeCl₄], contains two independent protonated 7-(1,3-dioxolan-2-ylmethyl)-3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione (doxofyllinium) and two tetrahedral tetrachloridoferrate(III) anions. In the doxofyllinium, two disordered methylene C atoms are observed in each dioxolane ring with an occupancy ratio of 0.54 (4):0.46 (4). In the crystal, molecules are connected by N—H⋯O hydrogen bonds and weak C—H⋯O and C—H⋯Cl interactions.

Related literature

For the biological activity of the drug doxofylline, see: Franzone et al. (1981 ▶, 1989 ▶); Zhao & Li (2001 ▶). For bond distances and angles in other tetrachloridoferrate(III) compounds, see: Barbaro et al. (1992 ▶); Bottomley et al. (1984 ▶). For the synthesis of doxofylline, see: Li et al. (1995 ▶).

Experimental

Crystal data

(C₁₁H₁₅N₄O₄)[FeCl₄]
M _r = 464.92
Tetragonal,
a = 20.2947 (4) Å
c = 9.0692 (4) Å
V = 3735.38 (19) Å³
Z = 8
Mo Kα radiation
μ = 1.40 mm⁻¹
T = 293 K
0.27 × 0.16 × 0.13 mm

Data collection

Bruker SMART APEX area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ▶) T _min = 0.775, T _max = 0.852
19874 measured reflections
6253 independent reflections
5589 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.099
wR(F ²) = 0.207
S = 1.30
6253 reflections
447 parameters
13 restraints
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.31 e Å⁻³
Absolute structure: Flack (1983 ▶), 2724 Friedel pairs
Flack parameter: 0.10 (4)

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); 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 global, I. DOI: 10.1107/S1600536810034720/jh2188sup1.cif

e-66-m1247-sup1.cif^{(27.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810034720/jh2188Isup2.hkl

e-66-m1247-Isup2.hkl^{(299.9KB, 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
N4—H4⋯O2ⁱ	0.86	1.93	2.774 (9)	165
N8—H8⋯O6ⁱⁱ	0.86	1.91	2.754 (9)	166
C5—H5⋯Cl5ⁱ	0.93	2.80	3.650 (11)	153
C8—H8B⋯O7ⁱⁱⁱ	0.97	2.29	3.114 (11)	142
C10—H10C⋯O5^iv	0.95	2.46	3.098 (11)	124
C10′—H10B⋯O5^iv	0.89	2.57	3.384 (11)	153
C10′—H10C⋯O5^iv	0.97	2.46	3.384 (11)	159
C16—H16⋯Cl1ⁱⁱⁱ	0.93	2.78	3.560 (11)	143
C19—H19A⋯O4^v	0.97	2.48	3.227 (11)	134
C19—H19A⋯O5	0.97	2.53	3.167 (11)	123
C22′—H22D⋯O1	0.97	2.58	3.242 (11)	126

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

Acknowledgments

We are grateful for financial support by the Natural Science Foundation of Tibet (2009–10–12) and the Natural Science Foundation of the Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education (2009–11–12).

supplementary crystallographic information

Comment

Doxofylline [7-(1,3-dioxolan-2-ylmethyl)-1,3-dimethyl-3,7- dihydro-1H-purine-2,6-dione] is a xanthine drug with anti-asthmatic (Franzone et al., 1989), antiinflammatory (Zhao et al., 2001), and bronchodilating activities (Franzone et al., 1981). Now we present here the structure of the title compound, (I).

In the title compound (Fig. 1), (I), the asymmetric unit contain two crystallographically independent molecules of doxofyllinium tetrachloroferrate(III). The furan rings of the doxofyllinium are disordered, and the five atoms of these rings aren't coplanar. The iron cation is tetra coordinated by chlorine anions, and it adopts a slightly distorted tetrahedral coordination with two angles smaller than the tetrahedral one, two almost equal to tetrahedral and two larger than tetrahedral (Table 1). Fe—Cl distances spanning the range 2.172 (3) Å-2.190 (4) Å, and Cl—Fe—Cl angles 107.41 (16)°-111.77 (15)°, are similar to those found in other tetrachloroferrate(III) (Bottomley et al., 1984; Barbaro et al., 1992).

In the crystal, doxofyllinium cations are linked by N8—H8···O6ⁱ and N4—H4···O2ⁱⁱ hydrogen bonds (Table 2). The weak C—H···O and C—H···Cl interactions further link (I), reinforcing the structure (Table 2).

Experimental

Doxofylline was synthesized according to Li et al. (1995). Doxofylline, hydrochloric acid and trichloride were dissolved in sufficient ethanol by heating to 333 K, where a yellow solution resulted. Crystals of (I) were formed by gradual evaporation of ethanol over a period of one week are 293 K.