A New Efficient Synthesis of p-Nitrocalix[4]arene

A new efficient synthesis of p-nitrocalix[4]arene from calix[4]arene by using nitrogen dioxide is described.The compound is an useful intermediates for the introduction of other functional groups to obtain N containing substituted calix[4]arene.The reaction mechanism is briefly discussed.     

Structure of 2-Amino-4-phenyl-9H-pyrimido[4,5-b]indole and Its Nitrate in Crystal and Solution

The crystal structures of 2-amino-4-phenyl-9H-pyrimido[4,5-b]indole and its nitrate were determined by XRD analysis. ¹³C NMR, XRD, and quantum-chemical data indicate that the acid proton is predominantly localized at the N(3) atom of the pyrimidine ring in both isolated nitrate molecules and in molecules in crystal and solution.     

Chloroaqua Complexes [M3S4(H2O)9?xClx](4?x)+ (M = Mo, W; x = 4, 6, 7) and Their Supramolecular Compounds with Cucur[8]uril

Compounds of trigonal cluster chloroaqua complexes with cucurbit[8]uril were synthesized by slowly evaporating HCl solutions of chalcogenides heterometallic cubane cluster complexes of molybdenum and tungsten with cucurbit[8]uril in air; the complexes were characterized by X-ray diffraction analysis: (H₃O)₈[Mo₃S₄(H₂O)_2.5Cl_6.5]₂Cl(PdCl₄)·(C₄₈H₄₈N₃₂O₁₆)· 29H₂O (a = 13.3183(17) Å, b = 13.7104(18) Å, c = 18.225(3) Å; α = 80.263(3)°, β = 77. 958(3)°, γ = 87.149(4)°, V = 3207.4(7) ų, space group P , Z = 1, ρ(calc) = 1.900 g/cm³), (H₃O)₄ [Mo₃S₄(H₂O)₃Cl₆]₂·(C₄₈H₄₈N₃₂O₁₆)₃·68H₂O (a = 21.413(6) Å, c = 49.832(10) Å; γ = 120°, V = 19788(8) ų, space group R , Z = 3, ρ(calc) = 1.695 g/cm³), (H₃O)₆ [Mo₃S₄(H₂O)₃Cl₆]₂Cl₂·(C₄₈H₄₈N₃₂O₁₆)·12H₂O (a = 15.881(2) Å, b = 17.191(2) Å, c = 23.276(4) Å; β = 98.865(15)°, V = 6278.7(15) ų, space group P2₁/c, Z = 2, ρ(calc) = 1.638 g/cm³), [W₃S₄(H₂O)₅Cl₄]₂·(C₄₈H₄₈N₃₂O₁₆)₃·35H₂O (a = 21.038(3) Å; α = 61.20(1)°, V = 6762.0(14) ų, space group R , Z = 1, ρ(calc) = 1.582 g/cm³). The [Mo₃S₄(H₂O)₃Cl₆]²⁻ anion complex was isolated as three geometrical isomers.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, H. G. Platas, F. M. Dolgushin, A. V. Gerasimenko, M. N. Sokolov, Z. A. Starikova, M. Yu. Antipin, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1049–1058, November–December, 2004.     

Synthesis,complexation, and photochemistry of benzobisthiazole-based bis(crown ether)

Benzobisthiazole-based bis(crown ether) was synthesized and its complexation with alkali and alkaline earth cations was studied. Photochemical transformations of the free ligand and its complexes with alkaline earth cations involve E,Z-photoisomerization and [2+2] photocycloaddition. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2056–2065, September, 2005.     

An Efficient Synthesis of Pyrazolo[3,4‐b]Pyridine Derivatives in Aqueous Media

A series of pyrazolo[3,4‐b]pyridines was synthesized by the reaction of 5‐aminopyrazole with benzylidenemalononitrile in aqueous media. The structures were characterized by IR, ¹H NMR, and elemental analysis and were further confirmed by X‐ray diffraction analysis.     

Thermodynamic Insight into the Origin of a Calix[n]arene-[60]fullerene Interaction and its Application to a Porphyrin-[60]fullerene Energy Transfer System

The calixarene-fullerene interaction,which causes only a slight change in the absorptionspectra, has been substantiated by calorimetricmeasurements: the H° values arecomparable with those obtained from the associationconstants estimated by a spectroscopic method. Furthermore, we determined the association constantbetween homooxacalix[3]arene and [60]fullerenederivatives with a porphyrin moiety by fluorescencespectra.     

Complexation of Some Amino Acids and Peptides by p-Sulfonatocalix[4]arene and Hexasodium p-Sulfonatocalix[6]arene in Aqueous Solution

The stability constants (log K), the reaction enthalpy( H) and entropy ( S) of the complexesformed between some amino acids (glycine, L-alanine,L-valine, L-leucine, L-phenylalanine, L-tryptophan,L-threonine, and L-lysine) and peptides (glycyl-glycine,glycyl-L-alanine, glycyl-L-leucine, glycyl-L-phenylalanine,L-leucyl-glycine, L-leucyl-L-alanine, glycyl-L-valine,L-leucyl-glycyl-glycine, and glycyl-glycyl-glycine) withp-sulfonatocalix[4]arene and hexasodiump-sulfonatocalix[6]arene in aqueous solutions by meansof calorimetric titration have been investigated. The reportedresults demonstrate that the amino acids and peptides under studyform complexes with both p-sulfonatocalix[4]areneand hexasodium p-sulfonatocalix[6]arene. In the case of theamino acids and peptides the complexation with water-solublecalixarenes in aqueous solution is favored by enthalpiccontributions and disfavored by entropic contributions. However,no influence of the ring size of the calixarenes upon thecomplexation is observed. By comparison with the reaction ofthe sodium salt of phenol-4-sulfonic acid with amino acids amacrocyclic effect in case of the calixarenes is possible.     

Topological investigations of molar excess volumes of quinoline with alkanols

Excess volumes V ^E of binary liquid mixtures of quinoline with alkanols have been determined from densities at 30°C as a function of composition. The excess volumes are negative over the whole mole fraction range for all the mixtures and decrease with increasing length of alkanol (C₁–C₁₀). The V^E data have been analyzed in terms of an approach which uses graph theoretical connectivity parameters of the third degrees for two components. The analysis gives information regarding associated species in the pure state and in the mixture. It is suggested that, in the mixture state, no change occurs in the association of alkanols.     

A new biodegradable polydepsipeptide microsphere for application in drug delivery systems

A sequential polydepsipeptide containing a tripeptide sequence L-alanyl-Lalanyl-ethyl L-glutamyl and an-hydroxy acid L-lactic acid, poly(Ala-Ala-Glu(OEt)-Lac), was synthesized to prepare the microspherical particles by the solvent evaporation process. In this case, the solvents play the most important role for the preparation of polydepsipeptide microspheres and, as an example, when 200 mg of the polydepsipeptide dissolved in 10 ml of 98/2% chloroform/dichloroacetic acid mixture was stirred at 400 rpm and 30 C, the microspherical particles with mean diameter of 58m were formed after pouring into 200 ml of 1% (w/v) poly(vinyl alcohol) solution. 17-Estradiol was incorporated into the particles, and the resulting particles were found to contain 5 mg of drug per 25 mg of the particle. The in vivo release of drug from the microspherical formulation was evaluated by measuring the pharmacological influence on rat prostate. It was found that the sufficient amount of drug, keeping the effective pharmacological influence, is supplied during the first 12-week period, followed by an incomplete supplying of drug intil the implant is perfectly degraded in vivo in the 25th week from the start of implantation.     

A concise synthesis of nornitidine via nickel- or palladium-catalyzed annulation

A concise method to synthesize benzo[c]phenanthridine alkaloid, nornitidine, was developed utilizing nickel- or palladium-catalyzed iminoannulation of an internal alkyne. The advantages of this strategy included readily available starting materials, inexpensive reagents, short reaction steps, and good yields.