Synthesis of macrocyclic systems from 4,4′-diamino-3,3′-bi-1,2,5-oxadiazole and 3(4)-amino-4(3)-(4-amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole 2-oxides

Oxidative cyclocondensation of 4,4′-diamino-3,3′-bi-1,2,5-oxadiazole and isomeric 3(4)-amino-4(3)-(4-amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole 2-oxides under the action of dibro-moisocyanurate gave 12- and 18-membered macrocyclic systems containing two or three bifurazanyl or furazanylfuroxanyl moieties linked by azo bridges. The latter were oxidized into azoxy groups with Caro’s acid in 20% oleum. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 631–638, March, 2008.     

Reactions of 2(3′-oxoalkyl)-1,3-cyclohexanediones with nitrogenous reagents

Condensed 1,4-dihydropyridines, which do not contain a substituent in position 4 and which are formed in the reaction of 2-(3-oxoalkyl)-1,3-cycohexanediones with ammonium acetate in acetic acid, undergo disproportionation. Pyridine bases are formed as the result of two competing reactions: disproportionation and oxidation of 1,4-dihydropyridines, intermediates in the heterocyclization of oxo-1,3-diketones with participation of the nitrogen atom, by air oxygen.N. G. Chernyshevskii Saratov State University Saratov 410026. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 647–651, May, 1994. Original article submitted April 22, 1994.     

Characterization and crystal structures of solvated N′-(4-hydroxy-3-nitrobenzylidene)-3-methylbenzohydrazide and N′-(4-dimethyl-aminobenzylidene)-3-methylbenzohydrazide

Two new solvated benzohydrazone derivatives N′-(4-hydroxy-3-nitrobenzylidene)-3-methylbenzohydrazide-methanol-water (2/1/1) 2(C₁₅H₁₃N₃O₄)·CH₃OH·H₂O (1) and N′-(4-dimethylamino-benzylidene)-3-methylbenzohydrazide methanol monosolvate C₁₇H₁₉N₃O·CH₃OH (2) are prepared and characterized by elemental analysis, ¹H and ¹³C NMR, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 17.084(2) Å, b = 12.706(1) Å, c = 15.412(1) Å, β = 113.207(1)°, V = 3074.1(4) ų, Z = 4, R ₁ = 0.0567, and wR ₂ = 0.1209. Compound 2 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 15.058(1) Å, b = 6.658(1) Å, c = 17.211(2) Å, β = 94.189(2)°, V = 1720.8(3) ų, Z = 4, R ₁ = 0.0611, and wR ₂ = 0.1594. X-ray diffraction indicates that the asymmetric unit of 1 contains two independent benzohydrazone molecules, one methanol and one water molecules. The asymmetric unit of 2 contains one benzohydrazone molecule and one methanol molecule. Benzohydrazone molecules of the compounds display trans configurations with respect to the C=N double bonds. The crystal structures of the compounds are stabilized by hydrogen bonds and weak π...π interactions.     

In situ synthesis and structure of FeCl4(4,4′-diethyl-4,4′-bipyh) (bipy = bipyridine)

A novel viologen(4,4′-bipyridinium)-based compound FeCl₄(4,4′-diethyl-4,4′-bipyH) (1) (bipy = bipyridine), in which 4,4′-diethyl-4,4′-bipyH (MQ ⁺) was generated in situ, is synthesized via the hydrothermal reaction and structurally characterized by single crystal X-ray diffraction. The crystal structure analysis reveals that the title compound features an isolated structure based on 4,4′-diethyl-4,4′-bipyH moieties and an iron atom terminally bound by four chlorine atoms. The 4,4′-diethyl-4,4′-bipyH moieties and (FeCl₄)^? anions are interconnected by hydrogen bonds to form a 3D supramolecular framework.     

Inclusion complexation of 4,4′-dihydroxybenzophenone and 4-hydroxybenzophenone with α- and β-cyclodextrins

The inclusion complexation behaviours of 4,4′-dihydroxybenzophenone (DHBP) and 4-hydroxybenzophenone (HBP) with α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were investigated using UV–visible fluorescence, time-resolved fluorescence, molecular modelling, scanning electron microscopy (SEM), FTIR, differential scanning calorimeter, X-ray diffraction, ¹H NMR and molecular modelling techniques. In both molecules, biexponential decay was observed in water, whereas triexponential decay was observed in the CD medium. The DSC thermogram of the DHBP/α-CD and DHBP/β-CD inclusion complex nanomaterials shows the endothermic peak at 60.8, 101.9, 119.6 and 112.8°C. The upfield chemical shift observed for HBP protons reveal that the phenyl ring (without hydroxyl substitution) entered the CD cavity and the hydroxyl group of HBP is exposed outside the CD cavity. The SEM image of DHBP appears as needle-shaped crystals on the micrometre scale, whereas the irregular bar shape was observed for HBP. Transmission electron microscopy images show that both guest molecules formed nano vesicles with α-CD and formed nano rods with β-CD.     

Synthesis of 4,4′-bis(dichloroamino)- and 4,4′-bis(chloroamino)-3,3′-azofurazans,the first representatives of dichloroamino- and chloroaminofurazans

First representatives of dichloroamino- and chloroaminofurazans, viz., 4,4′-bis(dichloroamino)- and 4,4′-bis(chloroamino)-3,3′-azofurazans, were synthesized by the chlorination of 4,4′-diamino-3,3′-azofurazan with sodium hypochlorite in the CH₂Cl₂—H₂O mixture.     

Kinetics of oxidation of 4,4′-biphenyldiol and of 4,4′-biphenoquinone by metal ions in aqueous perchlorate media: Reactions with Mn(III), Ce(IV) and Ag(II)

The kinetics and mechanisms of the oxidation of 4,4′-biphenyldiol ([1,1′-biphenyl]-4,4′-diol, I) to 4,4-biphenoquinone ([bi-2,5-cycloexadiene-(1,1′-cycloexadiene-(1,1′-ylidene)]-4,4′-dione, II) as well as the oxidative decomposition of II by means of some metal ions (Mn^III, Ce^IV and Ag^II) have been investigated in aqueous perchlorate media at different temperatures and acidities. The oxidation of I follows the empirical rate law: $\text{−}\text{d[I}\text{]}\text{d}\text{t}\text{= k[}\text{I][M}\text{]f([}\text{H}{}^{\mathrm{+}}\text{])}$, where M represents the oxidizing metal ion, and the decomposition of II: $\text{−}\text{d[II]}\text{d}\text{t}\text{= k′[}\text{II}\text{][}\text{M}\text{]}{}^{\mathrm{a}}\text{f′([}\text{H}{}^{\mathrm{+}}\text{])}$, where a = 1 for Ag^II and a = 0 for Ce^IV and Mn^III. The reaction mechanisms are proposed.     

High-spin complexes of iron(III) with ethylene glycol and 3(2′-hydroxyphenyl)-5-(4′-substituted phenyl) pyrazolines

Complexes of iron(III) with ethylene glycol and 3(2′-hydroxyphenyl)-5-(4′-substituted phenyl) pyrazolines, [Fe(OCH₂CH₂O)(C₁₅H₁₂N₂OX)] _m ? nH₂O and [Fe(C₁₅H₁₂N₂OX)₂(OCH₂CH₂OH)] (where OCH₂CH₂O and OCH₂CH₂OH = ethylene glycol moiety; C₁₅H₁₂N₂OX = 3(2′-hydroxyphenyl)-5-(4-X-phenyl)pyrazoline; X = H, CH₃, OCH₃, or Cl; m = 2–3 and n = 2–3) have been synthesized and characterized by elemental analysis (C, H, N, Cl, and Fe), molecular weight measurement, magnetic moment data, thermogravimetric analysis, molar conductance, spectral (UV-Vis, IR, and FAB mass), scanning electron microscopy, and X-ray diffraction studies. Bonding of ethylene glycol and pyrazolines in these complexes and the particle size of iron(III) complexes are discussed. Antibacterial and antifungal potential of free pyrazoline and some iron(III) complexes are also discussed.     

Synthesis and characterization of polycarbonates derived from N,N′-m-phenylenebis(3-hydroxybenzamide) and 4,4-bis(4-hydroxyphenyl)pentanoic acid anilide

The polycarbonates of N,N′-m-phenylenebis(3-hydroxybenzamide) (PBHB) and 4,4-bis(4-hydroxyphenyl)pentanoic acid anilide (BHPAA) were prepared by interfacial polymerization. They were characterized by inherent viscosity measurements, infra-red spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The PBHB polycarbonate was significantly more stable thermally than the BHPAA polycarbonate.     

Synthesis and Crystal Structure of 1′-Methyl-4′- (4-chlorophenyl)-1H-indole-3-spiro-2′-pyrrolidine- 3′-spiro-4'-(2'-phenyloxazole)-2,5'(3H,4'H)-dione

The title compound (C26H20ClN3O3) has been synthesized by 1,3-dipolar cycloaddition reaction from isatin, sarcosine and (Z)-4-(4-chlorobenzylidene)-2-phenyloxazol-5(4H)-one through a one-pot procedure, and its structure was confirmed by IR, 1H NMR, elemental analysis and single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1, with a = 9.3903(19), b = 11.398(2), c = 12.603(3) , α = 83.495(3), β = 68.988(3), γ = 67.178(3)°, V = 1160.1(4) 3, Z = 2, Mr = 457.90, Dc = 1.311 g/cm3, μ = 0.198 mm-1, F(000) = 476, the final R = 0.0489 and wR = 0.1144 for 3109 observed reflections with I > 2σ(I).     

Crystal and molecular structures of (3Z)-(±)-4-(2′-hydroxypropyl)amino-and (3Z)-4-(2′-hydroxyethyl)amino-pent-3-en-2-ones

An X-ray study of (3Z)-(±)-4-(2′-hydroxypropyl)amino-and (3Z)-4-(2′-hydroxyethyl)amino-pent-3-en-2-ones is reported. The bond lengths inside the H ring are equalized due to the classical N-H...O hydrogen bond between the carbonyl oxygen and the amino group. In the 4-(2′-hydroxyethyl)amino-pent-3-en-2-one crystal, due to the classical N-H...O bonds, infinite zigzag chains are formed along the 0b axis and arranged into a layered structure due to the weak C-H...O interactions. In (±)-4-(2′-hydroxypropyl)aminopent-3-en-2-one crystal, however, centrosymmetric dimers are formed, which are then linked by weak C-H...O intermolecular interactions to form a layered structure along the a0b plane.     

Reactions of Methyl 1-(Bromoacetyl)azulene-3-carboxylate with Thioamides and Thioureas: Synthesis of 1-(Thiazol-4-yl)-3-methoxycarbonylazulenes

Thiazole derivatives have attracted a great deal of interest owing to their physiological activities. In addition, thiazoles are also useful in dye and photographic industry.[1] In the present paper we report the synthesis of azulenes containing a thiazole moiety.     

Synthesis and Anti-HIV Activity of Trisubstituted (3′R, 4′R)-3′,4′- Di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK) Analogs

In our prior studies,3′,4′-di-O-(S)-camphanoyl-(+)-cis-khellactone(DCK,1,Figure1)and its derivatives including mono-and di-substituted DCK analogs were identified as a novel class of potent anti-HIV agents1-4.Because of its high potency and efficient syn-thesis,4-methyl-DCK25was chosen as a drug candidate for preclinical studies.How-ever,the low solubility and poor oral bioavailability of4-methyl-DCK limited its further development.Because high molecular hydrophobicity might be one re…     

Facile Synthesis of 2-(4-Hydroxybiphenyl-3-yl)-1H-indoles from Anilines and 5′-Bromo-2′-hydroxyacetophenone

2-Arylindoles are attractive scaffolds because they are found in many pharmacologically active molecules. In this study, we describe the facile synthesis of diverse 2-(2-hydroxyphenyl)-1H-indoles from anilines and 5′-bromo-2′-hydroxyacetophenone in two steps using palladium-catalyzed indole cyclization as a key reaction. The indole cyclization was primarily controlled by the substituent properties of anilines. Suzuki-coupling reactions of 2-(5′-bromo-2′-hydroxyphenyl)-1H-indoles with arylboronic acids provided the corresponding 2-(4-hydroxybiphenyl-3-yl)-1H-indoles in moderate yield.     

Synthesis, crystal structures, and magnetic properties of two three-dimensional octacyanotungstate(IV)- based bimetallic frameworks with 4,4′-bipyridine dioxide (4,4′-dpdo)

The reaction of [HN(n-C4H9)3]3[WV(CN)8]·4H2O, 4,4′-bipyridine dioxide(4,4′-dpdo), and MnCl2·4H2O or CuCl2·2H2O gives two new three-dimensional octacyanometalate-based bimetallic assemblies, {[Mn2 (4,4′-dpdo)(H2O)4] [WIV(CN)8]}·6H2O (1) and {[Cu2(4,4′-dpdo)(H2O)][W(CN)8]}·CH3OH·H2O (2). Compound 1 crystallizes in the orthorhombic system, space group P21212 with cell constants a=10.397(2) -, b= 11.321(2) -, c=12.295(3) - and Z=2, whereas 2 crystallizes in the monoclinic system, space group P21/c with cell con...     

Incompatible reaction for (3-4-epoxycyclohexane) methyl-3′-4′-epoxycyclohexyl-carboxylate (EEC) by calorimetric technology and theoretical kinetic model

(3-4-Epoxycyclohexane) methyl-3′-4′-epoxycyclohexyl-carboxylate (EEC) is a typical epoxy resin (EP). In Asia, due to the unstable reactive natures of EP, various thermal hazard and runaway reaction incidents have been occasioned by EP in the manufacturing process, such as fire, explosion, and toxic release, resulting in loss of life as well financial catastrophes and social outcries. Certain catalysis substances, H₂SO₄, acetic acid, or NaOH, may accelerate the reaction or curing rate for EP. However, an incompatible reaction with these chemical substances may induce a thermal hazard, causing a runaway excursion during the last stage. We employed thermogravimetry (TG) to obtain thermal stability parameters under non-isothermal conditions to evaluate the runaway reactions for EEC. The experimental data were compared with kinetics-based curve fitting to assess thermally hazardous phenomena by optimizing curve fitting on the kinetic parameters. The aim of this study was to estimate the incompatible hazards for EEC, provide thermal hazard information in order to determine the optimum operation conditions, and diminish the likelihood of fire and explosion accidents incurred by EP.     

Syntheses, Characterization and Crystal Structures of Two-dimensional 4,4′-Bipyridyl Lead Halides, PbI_2(4,4′-bpy) and PbBr_2(4,4′-bpy)

IntroductionLinear bidentate N,N′- donor complexes havebeen extensively used in recent years to obtain thepolymeric frameworks with potential applicationprospects in different areas of material sciences,such as electrical conductivity[1] ,magnetism[2 ] ,photomechanical behaviour[3 ] and catalysis[4～ 6] .Among them,4,4′- bipyridine( bpy) has beenproven to be able to form one- dimensional poly-mers[7] ,two- dimensional layers[4] ,and three- di-mensional frameworks exhibiting the interpene-tra…     

Crystal structures,Hirshfeld analysis,and energy framework analysis of two differently 3′-substituted 4-methylchalcones: 3′-(N=CHC6H4-p-CH3)-4-methylchalcone and 3′-(NHCOCH3)-4-methylchalcone

Two crystal structures of chalcones, or 1,3-diarylprop-2-en-1-ones, are presented; both contain a p-methyl substitution on the 3-Ring, but differ with respect to the m-substitution on the 1-Ring. Their systematic names are (2E)-3-(4-methylphenyl)-1-(3-{[(4-methylphenyl)methylidene]amino}phenyl)prop-2-en-1-one (C₂₄H₂₁NO) and N-{3-[(2E)-3-(4-methylphenyl)prop-2-enoyl]phenyl}acetamide (C₁₈H₁₇NO₂), which are abbreviated as 3′-(N=CHC₆H₄-p-CH₃)-4-methylchalcone and 3′-(NHCOCH₃)-4-methylchalcone, respectively. Both chalcones represent the first reported acetamide-substituted and imino-substituted chalcone crystal structures, adding to the robust library of chalcone structures within the Cambridge Structural Database. The crystal structure of 3′-(N=CHC₆H₄-p-CH₃)-4-methylchalcone exhibits close contacts between the enone O atom and the substituent arene ring, in addition to C…C interactions between the substituent arene rings. The structure of 3′-(NHCOCH₃)-4-methylchalcone exhibits a unique interaction between the enone O atom and the 1-Ring substituent, contributing to its antiparallel crystal packing. In addition, both structures exhibit π-stacking, which occurs between the 1-Ring and R-Ring for 3′-(N=CHC₆H₄-p-CH₃)-4-methylchalcone, and between the 1-Ring and 3-Ring for 3′-(NHCOCH₃)-4-methylchalcone.