(Di-tert-butylmethylphosphane)(eta2-di-tert-butylphosphanylphosphinidene)(triphenylphosphane)platinum(0).

The crystal structure of the title compound, [Pt(C(8)H(18)P(2))(C(9)H(21)P)(C(18)H(15)P)] or [(Ph(3)P)((t)Bu(2)PMe)Pt(eta(2)-(t)Bu(2)PP)], contains four molecules in the asymmetric unit with slightly different conformations. The P-P distances in the (t)Bu(2)PP ligands are similar for all four molecules [2.0661 (13)-2.0678 (13) A] and indicate a multiple character of the P-P bond in the (t)Bu(2)PP ligand. Molecules of the asymmetric unit can be assembled into a tetrahedron that fulfils the requirements for a rhombic disphenoid. The coordination of the Pt atom in all four molecules is square planar, with r.m.s. deviations from the PtP(4) planes in the range 0.03-0.05 A. All planes of the PtP(4) groups are approximately parallel to the ab plane of the unit cell. The structure represents an unusual unsymmetrical platinum phosphinidene derivative.

X-ray diffraction and high-resolution NMR spectroscopy of methyl 3,4-di-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-enopyranuronate.

Single-crystal X-ray diffraction and high-resolution (1)H and (13)C NMR spectral data for methyl 3,4-di-O-acetyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-enopyranuronate are reported. The (5)H(4) conformation was found to be the preferred form for this glycal, both in the crystal lattice and in solution. The factors determining the (4)H(5)<==>(5)H(4) conformational equilibrium for acetylated glycals are discussed.

Conformations of methyl 2,5-di-O-acetyl-beta-D-glucofuranosidurono-6,3-lactone and 1,2,5-tri-O-acetyl-beta-D-glucofuranurono-6,3-lactone in the crystal structure and in solution.

The single-crystal X-ray diffraction and high-resolution 1H and 13C NMR spectral data for methyl 2,5-di-O-acetyl-beta-D-glucofuranosidurono-6,3-lactone and 1,2,5-tri-O-acetyl-beta-D-glucofuranurono-6,3-lactone are reported. The lactones were synthesized as byproducts of reactions carried out to obtain methyl 1,2,3,4-tetra-O-acetyl-D-glucopyranuronate. The conformations of these lactones in the crystal structure and in solution are discussed. A 1T2-like conformation was found to be the preferred form for these lactones in both the crystal lattice and in solution.

9-(2,6-dichlorophenoxycarbonyl)-10-methylacridinium trifluoromethanesulfonate and its precursor 2,6-dichlorophenyl acridine-9-carboxylate.

The title compounds, C21H14Cl2NO2+.CF3O3S-, (I), and C20H11Cl2NO2, (II), form triclinic crystals. Adjacent cations of (I) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Together with the CF3SO3- anions, the antiparallel-oriented cations of (I) form layers in which the molecules are linked via a network of C-H...O and pi-pi interactions (between the benzene rings). These layers, in turn, are linked via a network of multidirectional pi-pi interactions between the acridine rings, and the whole lattice is stabilized by electrostatic interactions between ions. Adjacent molecules of (II) are oriented either parallel or antiparallel; in the latter case, they are related by a centre of symmetry. Parallel-oriented molecules are arranged in chains stabilized via C-H...Cl interactions. These chains are oriented either parallel or antiparallel and are stabilized, in the latter case, via multidirectional pi-pi interactions and more generally via dispersive interactions. Acridine and independent benzene moieties lie parallel in the lattices of (I) and (II), and are mutually oriented at an angle of 33.4 (2) degrees in (I) and 9.3 (2) degrees in (II).

2-Ethylphenyl acridine-9-carboxylate and 2,5-dimethylphenyl acridine-9-carboxylate.

The title compounds, 2-ethylphenyl acridine-9-carboxylate, C22H17NO2, (I), and 2,5-dimethylphenyl acridine-9-carboxylate, C22H17NO2, (II), form triclinic and monoclinic crystals, respectively. Related by a centre of symmetry, adjacent molecules of (I) are linked in the lattice via a network of C-H...pi and non-specific dispersive interactions. As a result, acridine moieties and independent phenyl moieties of (I) are parallel in the lattice. The molecules of (II), arranged in a 'head-to-tail' manner and related by a centre of symmetry, form pairs stabilized via C-H...pi interactions. These are linked in the crystal via dispersive interactions. Acridine and independent phenyl moieties lie parallel within the pairs, while adjacent pairs are perpendicular, forming a herring-bone pattern.

Synthesis, crystal structure, and high-resolution NMR spectroscopy of methyl 3-azido-2,3-dideoxy-4,6-di-O-p-tolylsulfonyl-alpha-D-xylo-hexopyranoside.

Synthesis of methyl 3-azido-2,3-dideoxy-4,6-di-O-p-tolylsulfonyl- and -6-O-p-tolylsulfonyl-alpha-D-xylo-hexopyranosides is presented. High-resolution 1H and 13C NMR spectral data for both compounds and their precursors, and the single-crystal X-ray diffraction analysis for methyl 3-azido-2,3-dideoxy-4,6-di-O-p-tolylsulfonyl-alpha-D-xylo-hexopyranoside are reported. The influence of the O-protective group on the chemical shift of adjacent atoms in the 1H and 13C NMR spectra is discussed.

X-ray diffraction and high-resolution NMR spectroscopy of methyl 3-azido-2,3-dideoxy-alpha-D-lyxo-hexopyranoside.

The single-crystal X-ray diffraction and high-resolution 1H and 13C NMR spectral data for the title compound are reported. The influence of the ring oxygen atom on the J(1,2e) and J(4,5) coupling constants for 2-deoxy-D-lyxo- and -D-xylo-hexopyranosides is discussed.

10-Methyl- and 9,10-dimethylacridinium methyl sulfate.

The title compounds, C(14)H(12)N(+).CH(3)O(4)S(-), (I), and C(15)H(14)N(+).CH(3)O(4)S(-), (II), respectively, crystallize with the planar 10-methylacridinium or 9,10-dimethylacridinium cations arranged in layers, parallel to the twofold axis in (I) and perpendicular to the 2(1) axis in (II). Adjacent cations in both compounds are packed in a 'head-to-tail' manner. The methyl sulfate anion only exhibits planar symmetry in (II). The cations and anions are linked through C-H.O interactions involving three O atoms of the anion, six acridine H atoms and the CH(3) group on the N atom in (I), and the four O atoms of the anion, three acridine H atoms and the carbon-bound CH(3) group in (II). The methyl sulfate anions are oriented differently in the two compounds relative to the cations, being nearly perpendicular in (I) but parallel in (II). Electrostatic interaction between the ions and the network of C-H.O interactions leads to relatively compact crystal lattices in both structures.

The solvent-free thermal dehydration of hexitols on zeolites.

Dehydration of galactitol, D-glucitol and D-mannitol at high temperature in the presence of molecular sieves without solvent under an argon atmosphere is described. Cyclodehydration products with retention or inversion of the configuration at asymmetric carbon atoms, were observed. Reaction of galactitol yielded racemic 1,4-anhydrogalactitol in a first step and then racemic 1,4:3,6-dianhydroiditol. Complete analytical separations of exhaustively O-acetylated reaction products were achieved by GC and structures were assigned using co-injection with standards.

9-(Trichloroacetylimino)acridine monohydrate.

The title compound, alternatively called N-acridin-9(10H)-ylidene-2,2,2-trichloroacetamide monohydrate, C(15)H(9)Cl(3)N(2)O.H(2)O, crystallizes in space group P2(1)/c with Z = 4. The acridine moieties are arranged in layers, tilted at an angle of 15.20 (4) degrees relative to the ac plane, while adjacent molecules pack in a head-to-tail manner. Acridine and water molecules form columns along the b axis held in place by a network of hydrogen bonds, which is the major factor stabilizing the lattice. The acridine molecule exhibits structural features of both the amino and imino forms, which could be due to the presence of the strong electronegative trichloroacetyl substituent at the exocyclic N atom.

9-Cyano-10-methylacridinium hydrogen dinitrate.

The title compound, C(15)H(11)N(2)(+).HN(2)O(6)(-), crystallizes in the monoclinic space group C2/c with four molecules in the unit cell. The planar 9-cyano-10-methylacridinium cations lie on crystallographic twofold axes and are arranged in layers, almost perpendicular to the ac plane, in such a way that neighbouring molecules are positioned in a 'head-to-tail' manner. These cations and the hydrogen dinitrate anions are linked through C-H.O interactions involving four of the six O atoms of the anion and the H atoms attached to the C atoms of the acridine moiety in ring positions 2 and 4. The H atom of the hydrogen dinitrate anion appears to be located on the centre of inversion relating two of the four O atoms engaged in the above-mentioned C-H.O interactions. In this way, columns of either anions or cations running along the c axis are held in place by the network of C-H.O interactions, forming a relatively compact crystal lattice.

Intercalation of imidazoacridinones to DNA and its relevance to cytotoxic and antitumor activity.

Imidazoacridinones (IA) are a class of antitumor agents which includes C-1311, an interesting drug in clinical trials. This study investigated the mechanism of IA binding to DNA for a series of 13 analogs that differ in their cytotoxic potency. Using C-1311 as a model compound, crystallographic, spectroscopic and biochemical techniques were employed to characterize drug-DNA interactions. X-ray crystallographic analysis revealed a planar structure of imidazoacridinone core that is capable of intercalative DNA binding. Accordingly, C-1311 binding to DNA followed 'classical' pattern observed for intercalation, as proved by the DNA topoisomerase I-unwinding experiments, with relatively weak binding affinity (K(i)=1.2 x 10(5)M(-1)), and the binding site size of 2.4 bp. Other IA also bound to DNA with the binding affinity in the range of 10(5)M(-1) and binding site size of 2-3 bp, suggesting a prevalence of the intercalative mechanism, similar to C-1311. Considerable DNA binding affinity was displayed by all the highly cytotoxic derivatives. However, none of the analyzed drug-DNA binding parameters was significantly correlated with IA biological activities such as cell growth, DNA and RNA synthesis inhibition, or tumor growth inhibition, which suggests that the IA ability to non-covalently bind to DNA is not crucial for their biological activity. These results show that the ability to intercalate into DNA is a prominent attribute of IA, although factors other than intercalative binding seem to be required for the biological activities of IA drugs.

2-Methylphenyl 2-methoxyacridine-9-carboxylate.

The title compound, C(22)H(17)NO(3), crystallizes in the monoclinic space group P2(1)/c with four molecules per unit cell. The molecules are arranged in centrosymmetric pairs, joined via the C and attached H atoms in the meta position relative to the methoxy group. These pairs are bonded in the crystalline phase as a result of non-specific dispersive interactions, and through a network of C-H...O interactions involving the non-bonded O atom of the carboxy group and, to some extent, the O atom of the methoxy group. The methoxy substituent lies in the plane of the almost planar acridine moiety and is directed towards the phenyl ester group. The phenyl ester group itself is twisted by 35.9 (5) degrees relative to the mean plane of the acridine moiety.

Synthesis, the crystal structure, and high-resolution NMR spectroscopy of methyl 4-O-acetyl-3-azido-2,3,6-trideoxy-6-iodo-alpha-D-arabino-hexopyranoside.

Selective tosylation followed by acetylation of methyl 3-azido-2,3-dideoxy-alpha-D-arabino-hexopyranoside (1) in pyridine at room temperature affords a mixture of methyl 4-O-acetyl-3-azido-2,3-dideoxy-6-di-O-p-tolylsulfonyl-alpha-D-arabino-hexopyranoside (4) and methyl 3-azido-2,3-dideoxy-4,6-di-O-p-tolylsulfonyl-alpha-D-arabino-hexopyranoside (3). Compound 4 undergoes nucleophilic displacement with sodium iodide in acetic anhydride to give methyl 4-O-acetyl-3-azido-2,3,6-trideoxy-6-iodo-alpha-D-arabino-hexopyranoside (7), whose crystal structure and (1H) and (13)C NMR data are reported. This compound adopts the 4C(1) conformation.