[5]Rotaxane and [5]Pseudorotaxane Based on Cucurbit[6]uril and Anchored to a Meso-tetraphenyl Porphyrin

Water soluble [5]rotaxane and [5]pseudorotaxane based on cucurbit[6]uril and anchored to a meso-tetraphenyl porphyrin have been synthesized and characterized by spectroscopic methods (¹H-NMR, ¹³C-NMR and UV), and by elemental analysis, and mass spectrometry. The preliminary results of the pH-driven switching properties of [5]rotaxane investigated through ¹H-NMR spectroscopy are reported. These results were compared with those obtained from a model porphyrin, which was prepared by the de-threading cucurbit[6]uril from [5]pseudorotaxane under basic conditions.Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Synthesis and characterization of a new pillar[5]arene-based [1]rotaxane

In this study, we reported the synthesis of three kinds of mono-functional pillar[5]arene derivatives PRI, PRII and R and their structures were studied by 1D and 2D NMR spectra and mass spectra. The 2D NMR spectra including ¹H-¹³C HSQC, ¹H-¹H COSY and NOESY spectra indicated that PRI and PRII are both stable self-included pseudo[1]rotaxanes in CDCl₃. These original structures are promising compounds for the design of pillar[5]-based [1]rotaxane. And the results showed that R could exist stable in CDCl₃ and DMSO because of the coordination of N-H?O hydrogen bonding interaction and C-H?π interaction.     

Cs[Cl3F10]: A Propeller‐Shaped [Cl3F10]− Anion in a Peculiar A[5]B[5] Structure Type

Reaction of CsF with ClF₃ leads to Cs[Cl₃F₁₀]. It contains a molecular, propeller‐shaped [Cl₃F₁₀]^? anion with a central μ₃‐F atom and three T‐shaped ClF₃ molecules coordinated to it. This anion represents the first example of a heteropolyhalide anion of higher ClF₃ content than [ClF₄]^? and is the first Cl‐containing interhalogen species with a μ‐bridging F atom. The chemical bonds to the central μ₃‐F atom are highly ionic and quite weak as the bond lengths within the coordinating XF₃ units (X = Cl, and also calculated for Br, I) are almost unchanged in comparison to free XF₃ molecules. Cs[Cl₃F₁₀] crystallizes in a very rarely observed A^[5]B^[5] structure type, where cations and anions are each pseudohexagonally close packed, and reside, each with coordination number five, in the trigonal bipyramidal voids of the other.     

Synthesis of Cucurbit[5]uril-Spermine-[2]Rotaxanes

Cucurbit[5]uril and decamethylcucurbit[5]uril are cyclic pentamers built from glycoluril or dimethylglycoluril respectively. Two different experimental methods have been used for the synthesis of the different [2]rotaxanes. The formed rotaxanes are characterized using ¹H-NMR spectroscopy, mass spectrometry and elemental analysis. In contrast to cucurbit[5]uril no [2]rotaxane could be obtained with decamethylcucurbit[5]uril.     

Design and synthesis of self-included pillar[5]arene-based bis-[1]rotaxanes

Two strategies for the design of new pillar[5]arene-based mechanically self-interlocked molecules (MSMs) are reported here. The first strategy is based on the construction of an intermediate pseudo[1]rotaxane followed by the desired bis-[1]rotaxane. The other one is based on the construction of the desired bis-[1]-rotaxane directly via a condensation reaction through host-guest interactions between a mono-functionalized pillar[5]arene and the axle. This compound has interesting self-assembly properties in methanol and some extended applications of this compound will be reported in the near future.     

1-Aza-5-stanna-5,5-dimethylbicyclo[3.3.01,5] octan und 1-aza-5-stanna-5-methyltricyclo[3.3.3.01,5] undecan,pentakoordinierte tetraorganozinnverbindungen

The synthesis of Me₂Sn(CH₂CH₂CH₂)₂NMe and MeSn(CH₂CH₂CH₂)₃N is reported. The transannular SnN interaction is confirmed by ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy.     

Synthesis of 5-Aryl-1,2,3,4-tetrahydrobenzo[a]phenanthridines

Previously unknown derivatives of tetrahydro[a]phenanthridine containing annelated benzoquinoline and cyclohexene nuclei were prepared by condensation of azomethines of the 2-naphthylamine series with cyclohexanone. The possibility of synthesis of such compounds without preliminarily preparing Schiff bases was demonstrated. The effect of substituents in the aromatic ring of the azomethine on the yield of the target products was elucidated. The IR, UV, ¹H NMR, and mass spectra of the synthesized compounds were discussed.     

Synthesis of a new calix[n]pyrrole: meso-pentaspirocyclohexyl calix[5]pyrrole

We describe the first synthesis of the novel meso-pentaspirocyclohexyl calix[5]pyrrole 2b. Anion-guest properties of the new compound were evaluated with respect to fluoride, chloride, and bromide tetrabutylammonium salts by ¹H NMR titration techniques in deuterated dichloromethane at 22 °C by following the induced shifts in the NH resonances upon complexation.     

Organic clays. Synthesis and structure of Na5[calix[4] arene sulfonate] · 12 H2O,K5[calix[4]arene sulfonate]·8 H2O,Rb5[calix[4]arene sulfonate]·5 H2O,and Cs5[calix[4] arene sulfonate] ·4 H2O

The title calixarenes all exist in the solid state as bilayers of anionic calixarenes in the cone configuration. These layers alternate with inorganic regions which contain the cations and the water molecules. The overall structures bear a close resemblance to those found for clay minerals. The sodium salt crystallizes in the triclinic space groupP witha = 10.998(6),b = 13.582(5),c = 14.472(5) Å, = 74.01(3), = 89.09(4), = 86.50(4)°, andZ = 2 forD _calc = 1.72 g cm^–3. Refinement based on 4727 observed reflections led to a conventionalR = 0.050. The potassium salt crystallizes in the triclinic space groupP witha = 11.815(9),b = 13.636(6),c = 14.040(9) Å, = 100.24(5), = 111.86(9), = 95,14(9)°, andZ = 2 forD _calc = 1.77 g cm^–3. Refinement based on 2977 observed reflections led toR = 0.15. The rubidium and cesium salts are isostructural and crystallize in the monoclinic space groupP2₁/n with parameters for Rb[Cs]a = 11.603(5) [11.704(3)],b = 28.607(8) [29.747(9)],c = 12.512(5) [12.604(4)] Å, = 91.70(4) [91.63(2)°], andZ = 4 forD _calc = 2.01 [2.24] g cm^–3. Refinement based on 1750 [4257] observed reflections led toR = 0.108 [0.075]. Disorder of the cations was observed for the rubidium and cesium salts. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82074 (95 pages).     

Synthesis of a series of diaminobenzo[f]- and diaminobenzo[h]pyrimido[4,5-b]quinolines as 5-deaza tetracyclic nonclassical antifolates

A series of diaminobenzo[f]- and diaminobenzo[h]pyrimido[4,5-b]quinolines 1–11 were designed as 5-deaza tetracyclic nonclassical, lipophilic antifolates. The compounds were designed as conformationally semi-rigid and rigid analogs of 2,4-diamino-6-phenyl- 12 and 2,4-diamino-7-phenylpyrido[2,3-d]pyrimidines 13 and 14 . The target compounds were synthesized by cyclocondensation of chlorovinyl aldehydes obtained from appropriately substituted 1- or 2-tetralone, with 2,4,6-friaminopyrimidine. Compounds 1–11 were evaluated as inhibitors of P. carinii and T. gondii dihydrofolate reductases. These pathogens cause fatal opportunistic infections in AIDS patients. In addition, the selectivity of these agents was evaluated using rat liver dihydrofolate reductase as the mammalian source. In general the benzo[f]pyrimido[4,5-b]quinolines 1–5 were more potent than the corresponding benzo[h]pyrimido[4,5-b]quinoline analogues 6–11 against P. carinii and rat liver dihydrofolate reductase and were equipotent against T. gondii dihydrofolate reductase. Compounds 6–11 were moderately selective towards T. gondii dihydrofolate reductase with IC₅₀S in the 10⁻⁷ M range. In contrast analogues 1–5 lacked selectivity against P. carinii or T. gondii dihydrofolate reductase and were, in general, potent inhibitors of rat liver dihydrofolate reductase with IC₅₀S in the 10⁻⁸ M range. Analogues 1 and 4 were evaluated against a series of tumor cell lines in vitro and were found to have moderate antitumor activity (IC50 10⁻⁶ M). The structure activity/selectivity relationships suggest that benzo[f]pyrimido analogues 1–5 with the phenyl ring substitution in the “upper” portion of the tetracyclic ring are better accommodated within the rat liver (mammalian) dihydrofolate reductase and P. carinii dihydrofolate reductase active sites compared to the benzo[h]pyrimido analogues 6–11 which have the phenyl ring substitution in the “lower” portion of the tetracyclic ring. In contrast T. gondii dihydrofolate reductase does not discriminate between the isomers and binds to both series of compounds with similar affinities.     

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [CrVIOF5]−, [CrVOF5]2−, [CrV2O2F8]2−, and [CrIVF6]2− Anions

Molten mixtures of XeF₆ and Cr^VIOF₄ react by means of F₂ elimination to form [XeF₅][Xe₂F₁₁][Cr^VOF₅] ⋅ 2 Cr^VIOF₄, [XeF₅]₂[Cr^IVF₆] ⋅ 2 Cr^VIOF₄, [Xe₂F₁₁]₂[Cr^IVF₆], and [XeF₅]₂[Cr^V₂O₂F₈], whereas their reactions in anhydrous hydrogen fluoride (aHF) and CFCl₃/aHF yield [XeF₅]₂[Cr^V₂O₂F₈] ⋅ 2 HF and [XeF₅]₂[Cr^V₂O₂F₈] ⋅ 2 XeOF₄. Other than [Xe₂F₁₁][M^VIOF₅] and [XeF₅][M^VI₂O₂F₉] (M=Mo or W), these salts are the only Group 6 oxyfluoro-anions known to stabilize noble-gas cations. Their reaction pathways involve redox transformations that give [XeF₅]⁺ and/or [Xe₂F₁₁]⁺ salts of the known [Cr^VOF₅]²⁻ and [Cr^IVF₆]²⁻ anions, and the novel [Cr^V₂O₂F₈]²⁻ anion. A low-temperature Raman spectroscopic study of an equimolar mixture of solid XeF₆ and CrOF₄ revealed that [Xe₂F₁₁][Cr^VIOF₅] is formed as a reaction intermediate. The salts were structurally characterized by LT single-crystal X-ray diffraction and LT Raman spectroscopy, and provide the first structural characterizations of the [Cr^VOF₅]²⁻ and [Cr^V₂O₂F₈]²⁻ anions, where [Cr^V₂O₂F₈]²⁻ represents a new structural motif among the known oxyfluoro-anions of Group 6. The X-ray structures show that [XeF₅]⁺ and [Xe₂F₁₁]⁺ form ion pairs with their respective anions by means of Xe- - -F–Cr bridges. Quantum-chemical calculations were carried out to obtain the energy-minimized, gas-phase geometries and the vibrational frequencies of the anions and their ion pairs and to aid in the assignments of their Raman spectra.     

Structural study of 5-methoxyfuro[3,2-e]imidazo[1,2-c]pyrimidine

The nmr and X-ray diffraction data of the novel ring system furo[3,2-e]imidazo[1,2-c]pyrimidine are reported in this paper. The crystal and molecular structure of this compound (C₉H₇N₃O₂·1/2H₂O) has been solved at room temperature. Crystals are monoclinic in a space group of P2/n with cell constants a = 9.982(8), b = 13.526(9) and c = 13.981(9) Å, β = 107.44(5)°, V = 1800.9 ų, Z = 8, D_x = 1.462 Mg·m^?3. The structure was solved by full matrix least square refinement giving a final R = 0.054 (Rw = 0.069) for 1263 reflections (I>3.0σ(I)). The compound is essentially planar, existing in two slightly structural different forms, A and B. These are held in pairs with symmetry related molecules by hydrogen bonds formed with two water molecules. Then the dimeric units are stacked parallel to the c axis to form the tridimensional packing.     

Radical deoxygenation of 3-azatricyclo[2.2.1.0]heptan-5-ols to 2-azabicyclo[2.2.1]hept-5-enes and 1,2-dihydropyridines

Additions of alkyl or aryl Grignard reagents, or pyridin-3-yl-lithiums or lithium alkoxides, to exo-5,6-epoxy-7-(tert-butoxycarbonyl)-2-tosyl-7-azabicyclo[2.2.1]hept-2-ene lead to 7-substituted-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols. Radical deoxygenations of 7-alkyl-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols give 7-alkyl-4-tosyl-2-azabicyclo[2.2.1]hept-5-enes, whereas 7-aryl-1-tosyl-3-azatricyclo[2.2.1.0^2,6]heptan-5-ols give 2-(arylmethyl)-5-tosyl-1,2-dihydropyridines.     

Synthesis of 2-Methyl-3-acetyl-5-oxo-5H-[1]benzopyrano[2,3-b]pyridine

For our synthetic work we needed the title compound. Literature survey revealed that 2-amino-4-oxo-4H-[1] benzopyran-3-carboxaldehyde (2-amino-3-formylchro-mone) can undergo condensation with diethyl malonate (or ethyl cyanoacetate) forming ethyl 2-hydroxy(or amino)-5-oxo-5H-[1]benzopyrano[2,3-b]pyridine-3-carboxylate¹.     

Recognition in water of bioactive substrates by a sulphonato p-tert-butylcalix[5]arene

The molecular recognition in water of neurotransmitter monoamine and trace amine hydrochlorides by p-tert-butylcalix[5]-arene 1 – bearing 4-sulphonatobutoxy groups at the lower rim – has been investigated. According to ¹H NMR measurements, the hydrophobic cavity of receptor 1 best binds tyramine hydrochloride, K_a = 5370 ± 870 M^? 1.     

Derivatives of exo-5-Aminomethyl-endo-5-methylbicyclo[2.2.1]hept-2-ene and exo-5-Aminomethyl-endo-5-methyl-exo-2,3-epoxybicyclo[2.2.1]heptane

exo-5-Aminomethyl-endo-5-methylbicyclo[2.2.1]hept-2-ene and its 2,3-epoxy derivative were synthesized, and their geometric parameters and conformational properties, in particular the barriers to rotation of the aminomethyl fragment about the exocyclic C⁵ÄC bond, were studied by the molecular-mechanics method (MMX) and compared with those found for structurally related exo-5-aminomethylbicyclo[2.2.1]hept-2-ene. The title compounds were brought into reactions with electrophilic reagents: arenesulfonyl chlorides, isocyanates, and isothiocyanates.     

The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 5. [1]Benzothieno[2,3-c]naphtho[2,1-f]-quinoline and [1]benzothieno[2,3-c]naphtho[1,2-g]quinoline

Two previously unknown heterocyclic ring systems, namely, [1]benzothieno[2,3-c]naphtho[2,1-f]quinoline ( 4 ) and [1]benzothieno[2,3-c]naphtho[1,2-g]quinoline ( 5 ) were synthesized via photocyclization of 3-chloro-N-(2-phenanthryl)benzo[b]thiophene-2-carboxamide ( 8 ) followed by chlorination and dechlorination. The total assignment of their ¹H- and ¹³C-nmr spectra was determined by utilizing inverse-detected HMQC and HMBC two-dimensional nmr spectroscopic methods.     

HALOACETYLATED ENOL ETHERS: 16[5] REGIOSPECIFIC SYNTHESIS OF 5-TRICHLOROMETHYL-PYRAZOLES

ABSTRACT

The regiospecific synthesis and isolation of three series of 5-trichloromethyl-pyrazoles 2f–j, 3a–j and 4a–j from the cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones (1a–f) or trichloroacetyl containing β-diketones (1g–j) with dry hydrazine and phenyl-hydrazine is reported. It was established by ¹H- and ¹³C-NMR spectroscopy that the 5-hydroxy-5-trichloromethyl-4,5-dihydro-1H-pyrazole intermediates 2a–j were formed quantitatively.     

Darstellung und Schwingungsspektren der Komplexe [MBr6]−, [Br5MN3]− und [Br5MNPPh3]− von Niob und Tantal Die Kristallstruktur von PPh4[NbBr6]

Preparation and vibrational spectra of the complexes [MBr₆]^?, [Br₅MN₃]^? and [Br₅MNPPh₃]^? of niobium and tantalum. Cyrstal structure of PPh₄[NbBr₆] The compounds PPh₄[MBr₆] and PPh₄[MBr₅N₃] are obtained by reaction of MBr₅ with PPh₄Br or PPh₄N₃, respectively, in CH₂Cl₂ solution (M ? Nb, Ta). The azido complexes PPh₄[MBr₅N₃] can also be obtained by reactions of the hexabromo complexes with iodine azide. According to its i.r. spectrum the symmetry of the [MBr₆]^? ion is lower than O_h in the solide state. This is corfirmed for PPh₄[NbBr₆] by a crystal structure analysis; it crystallizes in the monoclinic space group B2/b with four formula units in the unit cell and with the lattice constants a = 2301, b = 1777, c = 686 pm and γ = 96,6°. The structure was determined with X-ray diffraction data and was refined to a residual index of R = 0.055. The [NbBr₆]^? ion has the symmetry C_i, the deviations from O_h being small. In the azido complexes [MBr₅N₃]^? the azido groups are covalently linked with the metal. From [NbBr₅N₃]^? and PPh₃ the complex [Br₅Nb?N?PPh₃]^?, is obtained; for the analogous formation of the corresponding Ta complex photochemical activation is necessary. In this way the complex [Cl₅Nb?N?AsPh₃]^? can also be obtained. I.r. spectra of all the compounds are reported and assigned.