Synthesis and anion recognition of neutral receptors based on multiamide calyx[4]arene

~~Synthesis and anion recognition of neutral receptors based on multiamide calyx[4]arene~~     

Electrochemical Oxidative [4+2] Annulation for the π-Extension of Unfunctionalized Heterobiaryl Compounds

Considering their unique electronic properties and diverse biological activities, regioselective access to fused aromatic compounds is significantly important in the field of organic materials and pharmaceutical science. Herein, we developed electrochemical oxidative [4+2] annulation reactions of heterobiaryl compounds with alkynes or alkenes, leading to the formation of several polycyclic heteroaromatic compounds. This electrosynthetic methodology serves for the straightforward π-extension of unfunctionalized heterobiaryl compounds. The requirements of additional oxidants and prefunctionalization of starting materials are obviated. Through the in situ generation of heterobiaryl radical cation intermediates, various fused aromatic compounds were obtained with good yields and excellent regioselectivity.     

Synthesis and studies of new organic conductors based on ET and EDT-TTF with the [ZnBr4]2− anions

New layer organic conductors based on bis(ethylenedithio)tetrathiafulvalene (ET)₄ZnBr₄Solv (Solv stands for solvent) were synthesized in various halobenzenes as solvents (C₆H₅X, X = Cl, Br, F and C₆H₄Y₂, Y = Cl, Br), as well as based on ethylenedithiotetrathiafulvalene (EDT-TTF)₄MBr₄(1,1,2-C₂H₃Cl₃) (M = Zn, Mn) and (EDT-TTF)₉(ZnBr₄)₂. The crystal structure of (ET)₄ZnBr₄(C₆H₄Cl₂) at room temperature was established. It was found to be composed of alternating conducting layers with various structure of stacks formed of the ET radical cations. Their conductivity and ESR spectra were measured. The ET compounds obtained are organic metals up to the temperatures of 4.2, 72, 80, or 183 K (depending on the solvent: C₆H₄Cl₂, C₆H₅Cl, C₆H₅Br, or C₆H₅F, respectively); the replacement of the solvent with more bulky 1,2-dibromobenzene led to the formation of a semiconductor. The compounds (EDT-TTF)₄MBr₄(C₂H₃Cl₃) with M = Zn, Mn and (EDT-TTF)₉(ZnBr₄)₂ retain metallic character of conductivity up to the temperatures of 260, 280, and 210 K.     

Synthesis of enantiopure norbornane derivatives. Effect of bridgehead substituent on the π-facial selectivity of the reduction of 2-norbornanones and their oximes

One of the most important features of the synthesis of camphor-derived compounds is the control of the stereochemistry at the C2 position. According to this, reduction of bridgehead-substituted 2-norbornanones 1 and 2-norbornanoximes 3 has been considered by us as a very convenient method for the preparation of different classes of enantiomerically pure 1,2- and 1,3-difunctionalised norbornane derivatives. Factors controlling the stereoselectivity in these reductions, as well as the role played by the nature of the bridgehead functional groups are discussed.     

Syntheses and properties of poly (amide–imide)s based on 5,5′-bis[4-(4-trimellitimidophenoxy)phenyl]-hexahydro-4,7-methanoindan and aromatic diamines

 A novel polymer-forming diimide–diacid, 5,5′-bis[4-(4-trimellitimido phenoxy)phenyl]-hexahydro-4,7-methanoindan (II), was prepared by the condensation reaction of 5,5′-bis[4-(4-aminophenoxy)phenyl]-hexahydro-4,7-methanoindan with trimellitic anhydride. A series of novel aromatic poly(amide–imide)s (PAIs) containing polycyclic cardo groups was prepared by the direct polycondensation of II with various aromatic diamines using phosphorylation techniques. The polymers had inherent viscosities between 0.71 and 0.96 dl/g. The polymers were soluble in polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide, and could be cast from their DMAc solutions into transparent, flexible, and tough films, except for III _a . These films had yield strengths of 85–114 MPa, tensile strengths of 77–102 MPa, an elongation at break of 8–17%, and initial moduli of 2.0–2.7 GPa. Wide-angle X-ray diffraction revealed that the polymers are amorphous. The glass-transition temperatures of the polymers were in the range 242–312 °C. All the PAIs exhibited no appreciable decomposition below 430 °C, and their 10%-weight-loss temperatures were in the range 484–507 °C in nitrogen and 494–515 °C in air. Received: 26 January 1999 Accepted in revised form: 11 May 1999     

Total synthesis of benzo[c]phenanthridine alkaloids based on a microwave-assisted electrocyclic reaction of the aza 6π-electron system and structural revision of broussonpapyrine

Total syntheses of the des-N-methyl (nor) type of benzo[c]phenanthridine alkaloids 1a-f and 19 and benzo[c]phenanthridine alkaloids, chelerythrine (2d), and broussonpapyrine (2f) were achieved. The key step was the construction of tetracyclic 10,11-dihydrobenzo[c]phenanthridines using a microwave-assisted electrocyclic reaction of the 2-cycloalkenylbenzaldoxime methyl ether 4 as an aza 6π-electron system, which was derived in two steps from a Suzuki-Miyaura cross-coupling reaction of 2-bromobenzaldehyde 6 with 2-(3,4-dihydro-6,7-methylenedioxynaphthyl)boronic acid pinacol ester 7. In addition, the exact structure of broussonpapyrine (2f) (2,3,9,10-tetraoxygenated type) was determined to be chelerythrine (2d).     

Extending the Structures of the p-Sulfonatothiacalix[4]arene Dimers Through Second-sphere Coordination and π…π Stacking Interactions

Reactions of cobalt(II) nitrate or zinc(II) nitrate, tetrasodium p-sulfonatothiacalix[4]arene (Na₄H₄TCAS), and methylviologen dihexafluorophosphate (MV(PF₆)₂) afforded two isomorphous complexes, {[M(H₂O)₆]^2 + [MV]^2 + [(MV)₂M₂(H₂O)₄(H₂TCAS)₂]^4 ? }·14H₂O (M = Co, 1; Zn, 2). In these two complexes, each two thiacalixarenes form a dimer with C _i symmetry through the coordination of sulfonate groups, and the above dimers further extend their structures through second-sphere coordination and π…π stacking interactions into three-dimension nets.     

A new method for the formation of the imidazo[4′, 5′; 3,4] pyrido[2,3-b]indole ring: Formal synthesis of the alkaloids from marine origin grossularines-1 and 2

A new synthesis of the 2-dimethylamino-4-hydroxy-6-methoxymethyl-3H-imidazo[4′, 5′:3,4] pyrido[2,3-b]indole, used as key intermediate in the total synthesis of the alkaloids grossularines-1 and -2, based on the step-wise formation of the pyridine and imidazole rings, is described.     

An investigation of the crystalline structure of the quasi-two-dimensional metamagnet of composition [C6H22N4]4+[CuCl4]Cl2 (I), with [C6H22N4]4+=[1,4,7,10-tetraazadecane]·4HC1

[C₆H₂₂N₄]⁴⁺[CuCl₄ ^2–]Cl₂ (I) crystallizes in the monoclinic space groupP2₁/c with cell constantsa=15.573(2) Å,b=7.281(2),c=7.092(2),=91.496(14)°,V= 803.874 ų, andd(z= 2 mol/cell)=1.762 gm cm^–3. Data were collected in the range 4° 2 50°, for a total of 2662 reflections, of which 2201 were independent and hadI 3(I). These were used in the solution and refinement of the structure. TheF(hkl) _obs were corrected for absorption (=23.558 cm^–1) using Psi scan curves of eight suitable reflections, leading to relative transmission coefficient adjustments ranging from 0.9999 to 0.5722. Structural refinement converged atR(F)= 0.023 and R _W (F)=0.026. The coordination around the metal consists of polymeric, axially elongated, six-bonded, trigonal antiprismatic CuCl₆ species, not the hoped for, discrete, molecular CuCl₆ ^4– species implied by their chemical formulation. The crystalline lattice contains three different types of ions: the (C₆H₂₂N₄)⁴⁺ cation, a pair of Cl^– anions which are hydrogen bonded to the secondary ammonium (-NH₂ ⁺-) hydrogens of the cation, and a CuCl₄ ^2– anion. The latter is polymerized into two-dimensional sheets linked to each other by the agency of the cations, in which the two sets of terminal (-NH₃ ⁺) hydrogen bond to the axial Cl^– ligands. The Cu-Cl distances are 2.279, 2.315, and 2.847 Å. The distance between nearest coppers in adjacent sheets is 15.573(2)Å, the length of thea-axis. The magnetic behavior of the compound is that of a metamagnet, which requires a somewhat unusual set of conditions and is very rare in Cu²⁺ compounds. Comparison of the magnetic behavior of (I) with that of related compounds is made. The thermal behavior of (I) was studied using differential scanning calorimetric measurements in the range of 120 K to its melting(dec) point (463 K). It undergoes a phase transition from green (low temperature phase) to golden yellow (room temperature phase) at 168 K, another phase transition (golden yellow to red) at 340.6 K, and another at 383.2 K during which there is not evident color change. Finally, it melts with decomposition at ca. 463 K.     

Upper Rim Diester—bridged Calix[4] arenes and Oligocalix [4]—arenes：the Effects of the Length of Bridged Reagents on Their Distribution

A series of monobridged calix [4] arenes 3a-f,cyclic biscalix-[4] arenes 4a-f ,diametrically bridged at the upper rim with saturated aliphatic diester chians,have been synthesized,The results at diluted conditions show that the percentage of yields of mono-,bis- and oligo-calix[4] arenes are related to the legth of the chains ,With the shortening of the chains ,the percent-age of monocalix[4] arenes decreased ,All the calix [4] arene moieties are in a cone conformaiton according to the AB quar-tet pattern of the methylene protons between the phenolic rings in the ^1H NMR spectra.     

Calix[4]resorcinols bearing γ-aminoacetal groups on the upper rim. Synthesis and properties

Synthesis of new calix[4]resorcinol molecules with acetal groups on the upper rim associated with calixarene skeleton through γ-aminoalkyl spacers was performed. The condensation of the compounds studied with 2-methylresorcinol was studied.     

Syntheses and(Crystal Structures of Two New One-dimensional Double Hydrogen-bonding-chain Complexes [Ni(bipy)2Cl]·ClO4 and [Zn(bipy)2Cl]·BF4

Two new transition metal complexes, [Ni(bipy)2Cl]·ClO4 (bipy = 2,2'-bipyridine) 1 and [Zn(bipy)2Cl]·BF4 2, have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 crystallize in monoclinic space group P21/n with Z = 4. For 1, a = 10.776(1), b = 12.067(1), c = 16.146(2)(A), β= 93.021(2)o, V = 2031.9(4)(A)3, Mr = 505.98, Dc = 1.654 g/cm3, μ = 1.255 mm-1, F(000) = 1032, the final R = 0.0406 and wR = 0.1002 for 3983 observed reflections with Ⅰ ＞ 2σ(I). For 2, a = 10.758(4), b = 12.058(4), c = 16.135(5) (A), β = 104.57(1)o, V = 2025.7(12) (A)3, Mr = 500.00, Dc = 1.639 g/cm3, μ = 1.396 mm-1, F(000) = 1008, the final R = 0.0470 and wR = 0.1237 for 3759 observed reflections with Ⅰ ＞ 2σ(I). The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. A one-dimen- sional zigzag double hydrogen-bonding-chain is generated by the intermolecular M-bipy …anion…bipy--M hydrogen bonding interactions between the chelating ligands of bipy and anion.     

Construction of the Core of Pseudolaric Acid A and Mechanistic Studies on Intramolecular [4+3] Cycloaddition

Pseudolaric acid A (1), which exhibits antifungal activity, cytotoxicity against several tumor cell lines in vitro, as well as contraceptive effects in mice, is a diterpenoid compound isolated from Pseudolarix Kaemferi1. The unusual structural feature in this molecule is a trans arrangement of the lactone and acetoxy group at the fused junction of 5, 7-fused ring skeleton bearing four contiguous stereogenic centers. The synthetic challenges posed by these structural elements in a rather compa…     

A kinetic study on the iron(III)-promoted aquation of [Cr(C2O4)2(picolinato)]2− and [Cr(C2O4)2(2-pyridineacetato)]2− complexes

Two [Cr(C₂O₄)₂(AB)]^2– type complexes, obtained from the reaction of cis-[Cr(C₂O₄)₂(H₂O)₂]^– with the AB ligand, [AB = picolinic (pyac) or 2-pyridine-ethanoic acid (pyeac) anions], were converted into [Cr(C₂O₄)(pyac)(H₂O)₂]⁰ and [Cr(C₂O₄)(pyeac)(H₂O)₂]⁰ compounds, respectively via Fe^III-induced substitution of the oxalato ligand. The aquation products were separated chromatographically and their spectral characteristics and acid dissociation constants determined. The kinetics of the oxalato ligand substitution were studied with a 10–40 fold excess of Fe^III over [Cr^III] at [H⁺] = 0.2 M and at constant ionic strength 1.0 M (Na⁺, H⁺, Fe³⁺, ClO^– ₄). The reaction rate law is of the form: r = k _obs[Cr^III], where k _obs = kQ[Fe^III]/(1 + Q[Fe^III]). The first-order rate constants (k), preequilibria quotients (Q) and activation parameters derived from the k values have been determined. The reaction mechanism is discussed in terms of a Lewis acid catalyzed (induced) ligand substitution.     

Origin of the synchronicity on the transition structures of polar Diels-Alder reactions. Are these reactions [4 + 2] processes?

The transition structures (TSs) for a series of related Diels-Alder reactions between cyclopentadiene and mono-, di-, tri-, and tetracyanoethylene derivatives have been studied with use of DFT methods at the B3LYP/6-31G computational level. The increase of the electron-withdrawing substitution on ethylene increases the rate of these polar cycloadditions. However, the symmetric arrangement of cis and trans 1,2-di- and tetracyanoethylenes decreases the effectiveness of the substitution, which can be related to the symmetry found at the corresponding TSs. A DFT analysis of the global and local electrophilicity power of these series of cyano ethylenes provides a sound explanation about the nature of these synchronous processes. The present theoretical study is in agreement with the experimental outcomes.     

Synthesis, structure, and biological activity of [2.2]paracyclophanes. 7. Synthesis of 2-([2.2]paracyclophan-4-yl)pyridines,-tetrahydroquinolines, and-benzo[h]quinolines based on condensation of 4-(β-dimethylaminopropionyl)[2.2]paracyclophane with primary amines

Condensation of 4-(-dimethylaminopropionyl)paracyclophane with aliphatic aldehydes or cyclohexanones in the presence of hydroxylamine gave 2-([2.2]paracyclophan-4-yl)pyridines and-5,6,7,8-tetrahydroquinolines respectively. Reaction of these salts with -naphthylamine gives a mixture of paracyclophanyl substituted 1,2,3,4-tetrahydrobeno[h]quinoline and benzo[h]quinoline.For Communication 6, see [1].Russian University of National Friendship, Moscow 117198. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1069–1073, August, 1997.     

Synthesis, Characterization and Structural Determination of Ferrocene Derivatives Linked with Benzo[b]pyrans ——2-Amino-7,7-dimethyl-4-ferrocenyl-5-oxo-5,6, 7,8-tetrohydro-4H-chromene-3-carbonitrile

The title compound (C22H22N2O2Fe·CH3OH) was synthesized via a one-pot proce- dure from ferrocenylaldehyde, malononitrile and 5,5-dimethyl-1,3-cyclohexanedione using room temperature ionic liquid and pyridine as the catalysts, and characterized by elemental analysis, IR and 1H NMR. The structure was determined by X-ray single-crystal diffraction. The crystal belongs to monoclinic system, space group P21/n, with a = 9.7085(15), b = 22.951(4), c = 9.987(2) A, β = 112.494(3)°, V = 2055.9(6) A3, Z = 4, Mr = 402.28, Dc = 1.403 g/cm3, μ = 0.759 mm-1, F(000) = 868, the final R = 0.0536 and wR = 0.1449 for 4202 observed reflections with I > 2σ(I). The supramolecular single-helix chain of the title compound is formed by linking the building units with the hydrogen bond between N1 and N2. The adjacent chains are connected to a 2D layer by the hydrogen bond between N1 and O1. The adjacent layers are further linked by van der waals’ force. The CH3OH molecule is trapped in the interlayer.     

Quantum-chemical calculation of spectral characteristics and structure of complexes [Mg(DMF) i (CH3CN)6−i ]2+ and IR spectra of the tricomponent solutions Mg(ClO4)2-DMF-CH3CN

Geometry of complexes [Mg(DMF) _i (CH₃CN)_6?i ]²⁺ (i from 0 to 6) was optimized, IR spectra were calculated, and values of ΔG of the ligand replacement in the cation coordination sphere were estimated by DFT BLYP/6-31G** method. Regularities in variations of spectral and structural characteristics of the complexes at variation in their compositions were elucidated. Quantitative relations between the calculated changes in frequency and intensity of the IR bands ν_C≡N, ν_C-C, ν_C=O, and δ_OCN of the complexes and the respective values in the IR spectra of solutions CH₃CN-Mg(ClO₄)₂-DMF at varying composition of the binary solvent were established. The main regularities in the changes of the DMF ν_C=O band contour in the process of resolvation of Mg²⁺ ions were interpreted.     

Synthesis and characterization of a sensitive and selective Fe3+ fluorescent sensor based on novel sulfonated calix[4]arene‐based host‐guest complex

A novel fluorescent sensor was prepared from sulfonated calix[4]arene (SC4A) by the host-guest complexation method using the fluorescent dye rhodamine B (RB) as a structure-directing agent. The crystal structure of the host-guest complex (RB@(SC4A)₃) was confirmed by X-ray diffraction studies while its performance and sensing mechanism for metal ion pollutants were characterized using fluorescence and nuclear magnetic resonance spectroscopies. The results showed that RB@(SC4A)₃ had a triangular branch structure resulting from host-guest mediation of the interactions between the three SC4A host molecules and the three terminal groups of the guest molecule RB. The host-guest complex exhibited sensitive and selective sensing towards Fe³⁺ ions via a fluorescence quenching mechanism. The results indicated that RB@(SC4A)₃ could be a promising sensitive and selective fluorescent sensor for metal ion pollutants monitoring. It also provided new insights into the synthesis of calixarene-based host-guest complex.     

Structure of the Heterobimetallic Linear-Chain Polymeric Complex [NH_4]_n [WAgS_4]_n and Influence of Cationic Valence State on Configurations of Polymeric W/Ag/S Complexes

1INTRoDUCTIoNEarlyin1983,Mul1eretal.synthesizedthefirstM-Ag-Spolymericcomplex(Ph'P)[AgMoS'jandsupposeditslinearchainstructurefromitsresonanceRamanspectrumin1985:"2i.But,upto1993,thelinearchainstructure[(WAgS,)1j.wascharacterizedbyX-raysingle-crystalanalysis"'.Recently,aseriesofnovelpoly-mericW-Ag-Scomplexeshavebeensynthesizedinourlaboratory""3i.Herein,thedetailedsynthesisandstructureofthebrieflyreportedpolymericcomplex[NH,j.[WAgS'j."'aredescribed.Inaddition,conditionofformationofp…