Platinum(IV) Complexes of the 1,3,5-Triamino Analogue of the Biomolecule Cis-Inositol Designed as Innovative Antineoplastic Drug Candidates.

Metal complexes occupy a special place in the field of treatment and diagnostics. Their main advantages stem from the possibility of fine-tuning their thermodynamic properties and kinetic behavior in the biological milieu by applying different approaches such as properly constructed inner coordination sphere, appropriate choice of ligands, metal oxidation state, redox potential, etc., which are specific to these compounds. Here we discuss the design and synthesis of two octahedral cationic Pt(IV) complexes of the tridentate ligand all-cis-2,4,6-triaminocyclohexane-1,3,5-triol (taci) with composition, fac-[Pt(taci)I3]+, 1 and bis-[Pt(taci)2]4+, 2 as well as the potential for their application as antineoplastic agents. The complexes have been isolated in a solid state as: fac-[Pt(taci)I3]I·3H2O (1A), fac-[Pt(taci)I3]I (1B), fac-[Pt(taci)I3]I·2DMF (1C), bis-[Pt(taci)2](CO3)2·6H2O (2A) by changing the acidity of the reaction systems, the molar ratios of the reagents and the counterions, and by re-crystallization. The ligand taci is coordinated through the NH2-groups, each molecule occupying three coordination places in the inner coordination sphere of Pt(IV). Monitoring of the hydrolysis processes of 1A and 2A at different acidity showed that while 2A remained stable over the study period, the I--ions in 1A were successively substituted, with the main product under physiologically mimetic conditions being fac,cis-[Pt(taci)I(OH)2]+ (h2). The antiproliferative tests involved eight cancer cell models, among which chemosensitive (derived from leukemias and solid tumors) and chemoresistant human Acute myeloid leukemia lines (HL-60/Dox, HL-60/CDDP), as well as the non-malignant kidney' cells HEK-293T showed that the complexes 1A and 2A are characterized by a fundamentally different profile of chemosensitivity and spectrum of cytotoxic activity compared to cisplatin. The new Pt(IV) complexes were shown to be more effective in selectively inhibiting the proliferation of human malignant cells compared to cisplatin. Remarkable activity was recorded for 1A, which showed an effect (IC50 = 8.9 ± 2.4) at more than 16-fold lower concentration than cisplatin (IC50 = 144.4 ± 9.8) against the resistant cell line HL-60/CDDP. In parallel, 1A exhibited virtually the same cytotoxic effect against the parental HL-60 cells (IC50 = 9.0 ± 1.2), where cisplatin displays comparable chemosensitivity (IC50 = 8.3 ± 0.8). The determined resistance indices (RI~1) show unequivocally that the resistant lines are sensitive to both compounds tested; therefore, they are capable of overcoming the mechanisms of cisplatin resistance. The structural features of these compounds and their promising pharmacological properties justify their inclusion in the group of "non-classical metal-based antitumor compounds" and are a prerequisite for the admission of alternative mechanisms of action.

Crystal structure and Hirshfeld surface analysis of tris-(2,2'-bi-pyridine)-nickel(II) bis-(1,1,3,3-tetra-cyano-2-eth-oxy-propenide) dihydrate.

The title compound, [Ni(C10H8N2)3](C9H5N4O)2·2H2O, crystallizes as a racemic mixture in the monoclinic space group C2/c. In the crystal, the 1,1,3,3-tetracyano-2-ethoxypropenide anions and the water molecules are linked by O-H⋯N hydrogen bonds, forming chains running along the [010] direction. The bpy ligands of the cation are linked to the chain via C-H⋯π(cation) inter-actions involving the CH3 group. The inter-molecular inter-actions were investigated by Hirshfeld surface analysis and two-dimensional fingerprint plots.

HBr or not HBr? That is the question: crystal structure of 6-hydroxy-1,4-diazepane-1,4-diium dibromide redetermined.

Liu et al. [Chin. J. Struct. Chem. (1996). 15, 371-373] reported the structure of 6-hydroxy-1,4-diazepane di(hydrogen bromide), C5H12N2O·2HBr, which was interpreted in terms of neutral diazepane and HBr molecules. We found, however, ample evidence that the formation of an organic salt, consisting of a diammonium cation and two bromide anions, is more plausible. This interpretation is also in agreement with thermogravimetric analysis and with the observed solution behaviour. The crystal structure of 6-hydroxy-1,4-diazepane-1,4-diium dibromide, C5H14N2O2+·2Br-, measured at 142 K, crystallized in the orthorhombic space group P212121. The structure displays O-H...Br and N-H...Br hydrogen bonding. Contact distances are given. A search in the Cambridge Structural Database for the singly-bonded H-Br moiety revealed a total of 69 structures. The question, whether these structures really include HBr as neutral molecules or rather Br- anions and a protonated substrate such as an amine, is addressed.

Crystal structure of fac-bis-[bis-(pyridin-2-yl)methan-amine]-iron(II) 1,1,3,3-tetra-cyano-2-(di-cyano-methyl-idene)propane-1,3-diide, [Fe(dipa)2](tcpd).

In the title compound, [Fe(C11H11N3)2](C10N6), the FeII cation is coordinated by two bis(pyridin-2-yl)methanamine (dipa) ligands and has crystallographic twofold symmetry. There are deviations from ideal octa-hedral geometry due to the steric requirements of the ligands. The polynitrile 1,1,3,3-tetra-cyano-2-(di-cyano-methylid-ene)propane-1,3-diide (tcpd2-) dianion is disordered about an inversion center and is not coordinated to the Fe atom. The anion is not planar but has a propeller shape. In the crystal, weak N-H⋯N inter-actions between the amine H atoms of the dipa ligands and two nitrile groups of the anion form an alternating chain of cations and anions related by the C-centering of the unit cell.

Hafnium-Based Contrast Agents for X-ray Computed Tomography.

Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

Crystal structure of meso-di-µ-chlorido-bis-[bis-(2,2'-bi-pyridine)-cadmium] bis-(1,1,3,3-tetra-cyano-2-ethoxy-propenide) 0.81-hydrate.

The hydrated title salt, [Cd2Cl2(C10H8N2)4](C9H5N4O)2·0.81H2O, was obtained from the hydro-thermal reaction between 2,2'-bi-pyridine, cadmium(II) chloride and potassium 1,1,3,3-tetra-cyano-2-eth-oxy-propenide. The binuclear cation lies across a centre of inversion in the space group P21/c, with the other components in general positions. The cation has approximate, but non-crystallographic 2/m symmetry and each of the CdII atoms is a stereogenic centre, one having the Δ configuration and the other the Λ configuration. In the anion, one of the C(CN)2 units is disordered over two sets of atomic sites having occupancies 0.75 (2) and 0.25 (2). The cations are linked by two independent C-H⋯Cl hydrogen bonds to form a sheet of R22(14) and R42(24) rings.

Characterization of a Novel Hafnium-Based X-ray Contrast Agent.

OBJECTIVE: Characterization of BAY-576, a new x-ray contrast agent which is not based on iodine, but rather on the heavy metal hafnium. Compared with iodine, hafnium provides better x-ray absorption in the energy range of computed tomography (CT) and allows images of comparable quality to be acquired at a significantly reduced radiation dose. MATERIALS AND METHODS: A range of standard methods were used to explore the physicochemistry of BAY-576 as well as its tolerability in in vitro assays, its pharmacokinetics and toxicology in rats, and its performance in CT imaging in rabbits. RESULTS: BAY-576 is an extraordinarily stable chelate with a metal content of 42% (wt/wt) and with excellent water solubility. Formulations of 300 mg Hf/mL exhibited viscosity (3.3-3.6 mPa) and osmolality (860-985 mOsm/kg) in the range of nonionic x-ray agents. No relevant effects on erythrocytes, the coagulation, or complement system or on a panel of 87 potential biological targets were observed. The compound did not bind to plasma proteins of a number of species investigated. After intravenous injection in rats, it was excreted fast and mainly via the kidneys. Its pharmacokinetics was comparable to known extracellular contrast agents. A dose of 6000 mg Hf/kg, approximately 10 to 20 times the expected diagnostic dose, was well tolerated by rats with only moderate adverse effects. Computed tomography imaging in rabbits bearing a tumor in the liver demonstrated excellent image quality when compared with iopromide at the same contrast agent dose in angiography during the arterial phase. At 70% of the radiation dose, BAY-576 provided a contrast-to-noise ratio of the tumor, which was equivalent to iopromide at 100% radiation dose. CONCLUSIONS: The profile of BAY-576 indicates its potential as the first compound in a new class of noniodine x-ray contrast agents, which can contribute to the reduction of the radiation burden in contrast-enhanced CT imaging.

Hydrogen-bonding patterns in bis[2,4,6-triazaniumylcyclohexane-1,3,5-tris(olate)-κ(3)O,O',O'']germanium(IV) tetrachloride hexahydrate.

A first preliminary report on the crystal structure of a hydrated salt formulated as [Ge(taci)2]Cl4·13H2O (taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol) appeared more than 20 years ago [Ghisletta (1994). PhD thesis, ETH Zürich. Switzerland]. At that time it was not possible to discriminate unambiguously between the positions of some of the chloride ions and water O atoms, and disorder was thus postulated. In a new determination, a conclusive scheme of hydrogen bonding proves to be a particularly appealing aspect of the structure. Single crystals of the title compound, C12H30GeN6O6(4+)·4Cl(-)·6H2O or [Ge(taci)2]2Cl8·12H2O, were grown from an aqueous solution by slow evaporation of the solvent. The two [Ge(taci)2](4+) cations exhibit a double-adamantane-type structure with exclusive O-atom coordination and approximate D3d symmetry. The taci ligands adopt a zwitterionic form with deprotonated hydroxy groups and protonated amino groups. Both cations are hydrogen bonded to six water molecules. The structure of the hydration shell of the two cations is, however, slightly different. The {[Ge(taci)2]·6H2O}(4+) aggregates are interlinked in all three dimensions by further hydrogen bonds of the types N-H...Cl...H-N, N-H...O(H)2...H-N, (Ge)O...H-O(H)...H-N, N-H...O(H)-H...Cl...H-N, (Ge)O...H-O-H...Cl...H-N, N-H...O(H)-H...Cl...H-(H)O...H-N, (Ge)O...H-O-H...Cl...H-(H)O...H-N and Ge(O)...H-O-H...Cl...H-O-H...O(Ge).

Formation of lithium, sodium and potassium complexes with 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci).

Single crystals of (1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))lithium(I) diiodide dihydrate, [Li(C6H16N3O3)(C6H15N3O3)]I2·2H2O or [Li(Htaci)(taci)]I2·2H2O (taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol), (I), bis(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))sodium(I) iodide, [Na(C6H15N3O3)2]I or [Na(taci)2]I, (II), and bis(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))potassium(I) iodide, [K(C6H15N3O3)2]I or [K(taci)2]I, (III), were grown by diffusion of MeOH into aqueous solutions of the complexes. The structures of the Na and K complexes are isotypic. In all three complexes, the taci ligands adopt a chair conformation with axial hydroxy groups, and the metal cations exhibit exclusive O-atom coordination. The six O atoms of the resulting MO6 unit define a centrosymmetric trigonal antiprism with approximate D3d symmetry. The interligand O···O distances increase significantly in the order Li < Na < K. The structure of (I) exhibits a complex three-dimensional network of R-NH2-H···NH2-R, R-O-H···NH2-R and R-O-H···O(H)-H···NH2-R hydrogen bonds. The structures of the Na and K complexes consist of a stack of layers, in which each taci ligand is bonded to three neighbours via pairwise O-H···NH2 interactions between vicinal HO-CH-CH-NH2 groups.

Hydrogen bonding in polyamino-polyalcohols: a monohydrated cocrystal of 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol iodide and 1,3,5-triamino-1,3,5-trideoxy-cis-inositol.

In the title monohydrated cocrystal, namely 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol iodide-1,3,5-triamino-1,3,5-trideoxy-cis-inositol-water (1/1/1), C6H16N3O3(+)·I(-)·C6H15N3O3·H2O, the neutral 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci) molecule and the monoprotonated 1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol cation (Htaci(+)) both adopt a chair conformation, with the three O atoms in axial and the three N atoms in equatorial positions. The cation, but not the neutral taci unit, exhibits intramolecular O-H···O hydrogen bonding. The entire structure is stabilized by a complex three-dimensional network of intermolecular hydrogen bonds. The neutral taci entities and the Htaci(+) cations are each aligned into chains along [001]. In these chains, two O-H···N interactions generate a ten-membered ring as the predominant structural motif. The rings consist of vicinal 2-amino-1-hydroxyethylene units of neighbouring molecules, which are paired via centres of inversion. The chains are interconnected into undulating layers parallel to the ac plane, and the layers are further held together by O-H···N hydrogen bonds and additional interactions with the iodide counter-anions and solvent water molecules.

Formation and base hydrolysis of oxidimethaneamine bridges in CoIII-amine complexes.

cis-[CoL2](3+) (1a(3+)), trans-[CoL2](3+) (2a(3+)), cis-[Co(MeL)2](3+) (1b(3+)), and trans-[Co(MeL)2](3+) (2b(3+)), L = 1,4-diazepan-6-amine (daza) and MeL = 6-methyl-1,4-diazepan-6-amine (Medaza), were allowed to react as templates in acetonitrile with paraformaldehyde and triethylamine. Several Co(III) complexes, where two adjacent amino groups of two ligand moieties are interlinked by an oxidimethaneamine bridge, were obtained. Connection of a primary with a secondary amino group (prim-sec bridging) was found to be predominant. The singly and doubly bridged daza- and Medaza-derivatives 7a(3+), 9a(3+) and 7b(3+), 9b(3+) were characterized by crystal-structure analysis. The bridging process resulted in a slight lengthening of the mean Co-N distance, a red shift of the A1g-T1g transition, and an increase of the Co(III)/Co(II) reduction potential. Several minor components, which could be only partially separated by chromatographic methods, were also formed. The daza-derivatives 6a(3+) (prim-prim bridged) and 10a(3+) (bidentate coordination of one daza frame) formed in small quantities. The Medaza derivatives 3b(3+) and 4b(3+) (trans configuration of the Medaza frames, with additional pending carbinolamino groups), and 8b(3+) (with a methylideneimino group) represent intermediates of the condensation process. Their structure was again corroborated by X-ray diffraction. All bridged species (6a(3+), 7a(3+), 7b(3+), 8b(3+), 9a(3+), 9b(3+), and 10a(3+)) exhibited exclusively a cis orientation of the two diazepane frames, even if the trans configured 2a(3+) or 2b(3+) were used as starting materials. Molecular mechanics calculations indicate that in the bridged species with a trans configuration steric strain is substantially more pronounced. In alkaline aqueous media, 9a(3+) and 9b(3+) revealed a complete degradation of the bridges whereby the original 1a(3+) and 1b(3+) reformed. The pseudo-first-order rate constant k(obs) of the degradation reaction was found to depend linearly on OH(-) concentration. The degradation of the first bridge is about 100 times faster than the degradation of the second. The mechanism of formation and degradation of such oxidimethaneamine bridges is discussed.

Formation in aqueous solution of a non-oxido V(IV) complex with VN6 coordination. Potentiometric, ESI-MS, spectroscopic and computational characterization.

The behaviour of the system formed by V(IV)O(2+) ion with all-cis-2,4,6-trimethoxycyclohexane-1,3,5-triamine (tmca) was characterized in aqueous solution through the combined application of electron paramagnetic resonance (EPR) and UV-Vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), pH-potentiometry and DFT methods. The formation of an unusual non-oxido [V(tmcaH-2)2] species with VN6 coordination, with the ligand in the bianionic form, was demonstrated. The geometry, EPR and UV-Vis spectra and electronic structure of [V(tmcaH-2)2] were simulated with Gaussian 09 and ORCA software and the results were compared with those of similar oxido and non-oxido vanadium(iv) species formed by other polyamine and polyol related ligands, such as 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci), 1,3,5-trideoxy-1,3,5-tris(dimethylamino)-cis-inositol (tdci), cis-inositol (ino) and 1,3,5-trideoxy-1,3,5-trimethoxy-cis-inositol (tmci). The results indicate that V(IV)O(2+) species are formed in acid and weakly basic solution and that [V(tmcaH-2)2] is observed above pH 10. In the non-oxido complex, DFT calculations suggest that the two -NH2 groups are in trans position and that the pre-organization of the ligands favours the metal complexation and the formation of the hexa-coordinated species with VN6 coordination.

Poly[[(µ4-1,3,5-triamino-1,3,5-tride-oxy-cis-inositol)sodium] bromide].

In the structure of the title compound, {[Na(C6H15N3O3)]Br} n , the sodium cation and the bromide anion are both located on threefold rotation axes. The sodium cation is bonded to the three hy-droxy groups of one 1,3,5-triamino-1,3,5-tride-oxy-cis-inositol (taci) ligand, with the taci ligand residing around the same threefold rotation axis as the sodium ion. The coordination sphere of the sodium ion is completed by three amino groups of three neighbouring taci mol-ecules. Hence, this type of coordination constitutes a three-dimensional open framework with channels along the c axis which are filled with the bromide counter-anions. Each bromide ion forms three symmetry-related hydrogen bonds to both the hy-droxy and the amino groups of neighbouring taci ligands.

V(IV)O versus V(IV) complex formation by tridentate (O, N(arom), O) ligands: prediction of geometry, EPR 51V hyperfine coupling constants, and UV-Vis spectra.

Systems formed using the V(IV)O(2+) ion with tridentate ligands containing a (O, N(arom), O) donor set were described. Examined ligands were 3,5-bis(2-hydroxyphenyl)-1-phenyl-1H-1,2,4-triazole (H2hyph(Ph)), 4-[3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]benzoic acid (H3hyph(C)), 4-[3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]benzenesulfonic acid (H3hyph(S)), and 2,6-bis(2-hydroxyphenyl)pyridine (H2bhpp), with H3hyph(C) being an orally active iron chelator that is commercially available under the name Exjade (Novartis) for treatment of chronic iron overload arising from blood transfusions. The systems were studied using EPR, UV-Vis, and IR spectroscopies, pH potentiometry, and DFT methods. The ligands bind vanadium with the two terminal deprotonated phenol groups and the central aromatic nitrogen to give six-membered chelate rings. In aqueous solution the main species were the mono- and bis-chelated V(IV)O complexes, whereas in the solid state neutral non-oxido V(IV) compounds were formed. [V(hyph(Ph))2] and [V(bhpp)2] are hexacoordinated, with a geometry close to the octahedral and a meridional arrangement of the ligands. DFT calculations allow distinguishing V(IV)O and V(IV) species and predicting their structure, the (51)V hyperfine coupling constant tensor A, and the electronic absorption spectra. Finally, EPR spectra of several non-oxido V(IV) species were compared using relevant geometrical parameters to demonstrate that in the case of tridentate ligands the (51)V hyperfine coupling constant is related to the geometric isomerism (meridional or facial) rather than the twist angle Φ, which measures the distortion of the hexacoordinated structure toward a trigonal prism.

(S)-2,2'-Dihy-droxy-N,N'-(6-hy-droxy-hexane-1,5-di-yl)dibenzamide.

In the title compound, C(20)H(24)N(2)O(5), the dihedral angle between the two roughly planar salicyl-amide fragments [r.m.s. deviations = 0.043 (2) and 0.149 (2) Å] is 25.50 (5)°. The mol-ecular conformation is stabilized by intra-molecular O-H⋯O hydrogen bonds involving phenol -OH groups and amide O atoms. Inter-molecular hy-droxy-meth-yl-amide O-H⋯O and amine-hy-droxy-methyl N-H⋯O hydrogen bonds form infinite chains along the b axis. These chains are further inter-linked by amine-amide N-H⋯O and phenol-phenol O-H⋯O inter-actions, thus giving layers parallel to (001).

Tris(cis-2-hy-droxy-cyclo-hexane-1,3,5-tri-aminium) hydrogen sulfate octa-chloride dihydrate.

The 2-hy-droxy-cyclo-hexane-1,3,5-triaminium (= H(3)L(3+)) cation of the title compound, 3C(6)H(18)N(3)O(3+)·8Cl(-)·HSO(4) (-)·2H(2)O, exhibits a cyclo-hexane chair with three equatorial ammonium groups and one axial hy-droxy group in an all-cis configuration. The hydrogen sulfate anion and two water mol-ecules lie on or in proximity to a threefold axis and are disordered. The crystal structure features N-H⋯Cl and O-H⋯Cl hydrogen bonds. Three C(3)-symmetric motifs can be identified in the structure: (i) Two chloride ions (on the C(3)-axis) together with three H(3)L(3+) cations constitute an [(H(3)L)(3)Cl(2)](7+) cage. (ii) The lipophilic C(6)H(6)-sides of three H(3)L(3+) cations, which are oriented directly towards the C(3)-axis, generate a lipophilic void. The void is filled with the disordered water mol-ecules and with the disordered part of the hydrogen sulfate ion. The hydrogen atoms of these disordered moieties were not located. (iii) Three H(3)L(3+) cations together with one HSO(4) (-) and three Cl(-) counter-ions form an [(HSO(4))(H(3)L)(3)Cl(3)](5+) cage. Looking along the C(3)-axis, these three motifs are arranged in the order (cage 1)⋯(lipophilic void)⋯(cage 2). The crystal studied was found to be a racemic twin.

Redetermination of 1,3-diammonio-1,2,3-tride-oxy-cis-inositol dichloride.

The crystal structure of the title compound, C(6)H(16)N(2)O(3) (2+)·2Cl(-), has been reported previously by Palm [Acta Cryst. (1967 ▶), 22, 209-216] from Weisenberg camera data, with R1 = 10.5%, isotropic refinement of non-H atoms and H atoms not located. We remeasured a data set of the title compound and present a more precise structure determination. The asymmetric unit contains two unique 1,3-diammonio-1,2,3-tride-oxy-cis-inositol cations and four Cl(-) counter-ions. The cyclo-hexane rings of both inositol cations adopt chair conformations with two axial hy-droxy groups. An extended network of hydrogen bonds is formed. The four chloride counter ions are hydrogen bonded to the hydroxy and ammonium groups of the cations by N-H⋯Cl and O-H⋯Cl interactions. The cations are aligned into wavy layers by cation⋯cation interactions of the form N-H⋯O(ax), N-H⋯O(eq) and O(ax)-H⋯O(eq). Intramolecular hydrogen bonding between the axial hydroxy groups is, however, not observed.

1,3-Diammonio-1,2,3-tride-oxy-cis-inositol sulfate.

In the crystal structure of the title compound, C(6)H(16)N(2)O(3) (2+)·SO(4) (2-), each cation forms three O-H⋯O and five N-H⋯O hydrogen bonds to six neighbouring sulfate anions. In addition, interlinking of the cations by N-H⋯O interactions is also observed. The cyclo-hexane ring adopts a chair conformation with two axial hy-droxy groups. Although the separation of 2.928 Šis almost ideal for a hydrogen bond, intra-molecular hydrogen bonding between these two hy-droxy groups is not observed.

4,6-Dinitro-pyrogallol.

In the title mol-ecule, C(6)H(4)N(2)O(7), the two nitro groups are tilted with respect to the aromatic ring by 11.2 (1) and 10.9 (1)°. All three hy-droxy groups are involved in the formation of bifurcated intra- and inter-molecular O-H⋯O hydrogen bonds. The crystal packing exhibits short O⋯O distances of 2.823 (2) Šbetween two O atoms of the nitro groups.

1,2,3-Trimeth-oxy-4,5,6-trinitro-benzene.

In the title mol-ecule, C(9)H(9)N(3)O(9), the three neighbouring nitro groups are tilted with respect to the benzene mean plane by 75.8 (1), 27.7 (1) and 68.1 (1)°. The methyl C atoms of the three neighbouring meth-oxy groups deviate from this plane by 0.976 (4), -1.425 (4) and 0.632 (4) Å. The crystal packing exhibits weak C-H⋯O inter-actions.