Cyclisation of benzils

Treatment of several substituted benzils [3,3′- and 4,4′-dimethyl-; 2,2′-, 3,3′- and 4,4′-dichloro-; 3,3′-dibromo-; 4-(N,N-dimethylamino)-] with an excess of chlorosulfonic acid gave the corresponding 3-chloro-2-phenylbenzofuran disulfonyl dichlorides. Disubstitution was confirmed by microanalytical and spectral data for the corresponding bis(N,N-dimethylaminsulfonamides). The positions of electrophilic substitution were not confirmed with 3,3′-dimethyl-, 2,2′- and 3,3′-dichlorobenzils. With 4,4′-dichlorobenzil, a smaller amount of chlorosulfonic acid enabled the isolation of 3,6,4′-trichloro-2-phenylbenzofuran-5-sulfonyl chloride, which was identified by X-ray analysis of the N,N-dimethylsulfonamide. The cyclisation failed with 3,3′-dimethoxy-, and 3,3′- and 4,4′-dinitrobenzils. The results have been interpreted mechanistically.     

Syntheses and Crystal Structures of Two One-Dimensional Chain Copper Benzoylacetone Complexes Bridged Through Azobispyridine Ligands

Two copper complexes [Cu(bzac)₂(4,4′-azpy)]·H₂O (1) and [Cu(bzac)₂(3,3′-azpy)] (2) (bzac = benzoylacetone, 4,4′-azpy = 4,4′-azobispyridine, 3,3′-azpy = 3,3′-azobispyridine) have been synthesized and characterized. The crystal structures were determined by X-ray diffraction analysis. In crystals of Complexes 1 and 2, the copper atoms have distorted octahedral symmetry. The two compounds possess very similar one-dimensional linear chains linked through the rod-like 4,4′-azpy or 3,3′-azpy ligands.     

Synthesis of polymer intermediates containing the hexafluoroisopropylidene group via functionalization of 2,2-diphenylhexafluoropropane

The title compound was synthesized by hydrogenolysis of its precursor 2,2-bis(4-trifluoromethanesulfonatophenyl)hexafluoropropane ( 2 ) in the presence of a base. 2,2-Diphenylhexafluoropropane ( 6 ) can be appropriately functionalized at the 3,3′-positions to give the diamino ( 7 ), dibromo ( 11 ), dicarboxaldehydo ( 13 ), 3-ethynyl-3′-carboxaldehydo ( 14 ) derivatives which are important monomers in the synthesis of various high-temperatures resistant polymers and oligomers containing the hexafluoroisopropylidene (6F) group. 2,2-Bis(4-triflatophenyl)hexafluoropropane ( 2 ) undergoes quantitative dinitration at the 3,3′-positions to yield 2,2-bis(3-nitro-4-triflatophenyl)hexafluoropropane ( 3 ) which ultimately leads to the 3,3′-diamino-4,4′-bis(arylamino) ( 5 ) and 3,3′-diamino-4,4′-dihydroxy ( 8 ) derivatives which are specifically designed for phenylbenzimidazole, benzimidazoquinazoline, and benzoxazole polymers and oligomers.     

Dense Energetic Nitraminofurazanes

3,3′‐Diamino‐4,4′‐bifurazane ( 1 ), 3,3′‐diaminoazo‐4,4′‐furazane ( 2 ), and 3,3′‐diaminoazoxy‐4,4′‐furazane ( 3 ) were nitrated in 100 % HNO₃ to give corresponding 3,3′‐dinitramino‐4,4′‐bifurazane ( 4 ), 3,3′‐dinitramino‐4,4′‐azofurazane ( 5 ) and 3,3′‐dinitramino‐4,4′‐azoxyfurazane ( 6 ), respectively. The neutral compounds show very imposing explosive performance but possess lower thermal stability and higher sensitivity than hexogen (RDX). More than 40 nitrogen‐rich compounds and metal salts were prepared. Most compounds were characterized by low‐temperature X‐ray diffraction, all of them by infrared and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and by differential scanning calorimetry (DSC). Calculated energetic performances using the EXPLO5 code based on calculated (CBS‐4M) heats of formation and X‐ray densities support the high energetic performances of the nitraminofurazanes as energetic materials. The sensitivities towards impact, friction, and electrostatic discharge were also explored. Additionally the general toxicity of the anions against vibrio fischeri, representative for an aquatic microorganism, was determined.     

Syntheses of Bissydnone Derivatives and Studies of Their Biological Activities

A new method to prepare 3,3′-ethylenebissydnone (40%), 3,3′-tetramethylenebissydnone (37%) and 3,3′-hexamethylenebissydnone (43%) from the corresponding alkylene diamine with paraformaldehyde and potassium cyanide were investigated. Some new bissydone: ?3,3′-trimethylenebissydnone (6%), 3,3′-(4,4′-diphenyl)bissydnonylmethane (9%) and 3,3′-(4,4′-diphenyi)bissydnonyl ether (28%) were synthesized from the corresponding diamine, paraformaldehyde, sodium bisulfite and potassium cyanide. Biological test of 3,3′-(4,4′-diphenyl)bissydnonylmethane shows significant response for coronary dilgtion test, inhibition of collagen induced platelet aggregation and moderate carditropic response. 3,3′-(4,4′-Diphenyl)bissydnonyl ether also shows inhibition of collagen induced platelet aggregation and moderate carditropic response.     

SYNTHESIS AND CHARACTERIZATION OF HIGHLY ORGANO-SOLUBLE POLYIMIDES BASED ON ALICYCLIC 1,8-DIMETHYL-BICYCLO[2.2.2]OCT-7- ENE-2,3,5,6-TETRACARBOXYLIC DIANHYDRIDE AND AROMATIC DIAMINES

Organo-soluble alicyclic polyimides (ALPIs) were synthesized from an alicyclic dianhydride, 1,8-dimethylbicyclo[2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (DMEA) and several multialkyl-substituted 4,4′-diaminodiphenylmethane compounds, including 3,3′-dimethyl-4,4′-diaminodiphenyl methane (DMDA), 3,3′,5,5′-tetramethyl-4,4′-diaminodiphenyl methane (TMDA) and 3,3′,5,5′-tetraethyl-4,4′-diaminodiphenylmethane (TEDA). For comparison, the aromatic polyimides (ARPIs) were synthesized from the aromatic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and the same diamines. The ALPIs exhibited better solubility and transparency,but worse thermal stabilities and mechanical properties than those of the ARPIs. And the ALPIs could be dissolved in common organic solvents, such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), chloroform, tetrahydrofuran, m-cresol and so on. The ALPI films had an UV-Vis cut-off at 320 nm and a transmittance of higher than 80% in the visible region. In addition, the ALPIs showed thermal decomposition temperatures (Td) of about 450℃, which was nearly 100℃ lower than that of the ARPIs.     

Synthesis and properties of novel polyimides derived from 2,2′,3,3′‐benzophenonetetracarboxylic dianhydride

A new synthetic route to 2,2′,3,3′‐BTDA (where BTDA is benzophenonetetracarboxylic dianhydride), an isomer of 2,3′,3′,4′‐BTDA and 3,3′,4,4′‐BTDA, is described. Single‐crystal X‐ray diffraction analysis of 2,2′,3,3′‐BTDA has shown that this dianhydride has a bent and noncoplanar structure. The polymerizations of 2,2′,3,3′‐BTDA with 4,4′‐oxydianiline (ODA) and 4,4′‐bis(4‐aminophenoxy)benzene (TPEQ) have been investigated with a conventional two‐step process. A trend of cyclic oligomers forming in the reaction of 2,2′,3,3′‐BTDA and ODA has been found and characterized with IR, NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and elemental analyses. Films based on 2,2′,3,3′‐BTDA/TPEQ can only be obtained from corresponding polyimide (PI) solutions prepared by chemical imidization because those from their polyamic acids by thermal imidization are brittle. PIs from 2,2′,3,3′‐BTDA have lower inherent viscosities and worse thermal and mechanical properties than the corresponding 2,3′,3′,4′‐BTDA‐ and 3,3′,4,4′‐BTDA‐based PIs. PIs from 2,2′,3,3′‐BTDA and 2,3′,3′,4′‐BTDA are amorphous, whereas those from 3,3′,4,4′‐BTDA have some crystallinity, according to wide‐angle X‐ray diffraction. Furthermore, PIs from 2,2′,3,3′‐BTDA have better solubility, higher glass‐transition temperatures, and higher melt viscosity than those from 2,3′,3′,4′‐BTDA and 3,3′,4,4′‐BTDA. Model compounds have been prepared to explain the order of the glass‐transition temperatures found in the isomeric PI series. The isomer effects on the PI properties are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2130–2144, 2004     

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.     

Phase behavior of some polyamic acid plus ether systems

Polyamic acids, prepared by reacting 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride with 3,3′-diaminobenzophenone and with 4,4′-diaminobenzophenone, were dissolved in tetrahydrofuran and in bis(2-methoxyethyl) ether at concentrations up to 40 wt %. Reversible phase separation was observed when these systems were heated. Evidence cited indicates that all observed phases are isotropic, notwithstanding the fact that a number of aromatic polyamides are mesogenic.     

The Crystal Structure of Biphenyltetracarboxylic Dianhydride Isomers

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Six new metal-organic frameworks with multi-carboxylic acids and imidazole-based spacers: syntheses, structures and properties

Six new metal-organic frameworks [Cu(obba)(bimb)·(obbaH(2))](n) (1), [Cu(obba)(bimb)](n) (2), [Zn(2)(obba)(2)(bimb)(2)(DMF)(2)(H(2)O)(3.5)](n) (3), [Ni(3)(2,2',4,4'-bptcH)(2)(bimb)(2)(H(2)O)(2)·(H(2)O)(2)](n) (4), [Ni(2)(bimb)(3)(H(2)O)(6)·(aobtc)·(DMF)(2)·(H(2)O)(2)](n) (5) and [Cd(3,3',4,4'-bptcH(2))(H(2)O)·(bimb)](n) (6), were obtained by reactions of 4,4'-bis(1-imidazolyl)biphenyl (bimb) and multi-carboxylic acids of 4,4'-oxybis(benzoic acid) (obbaH(2)), 2,2',4,4'-biphenyltetracarboxylate acid (2,2',4,4'-bptcH(4)), azoxybenzene-3,3',5,5'-tetracarboxylic acid (aobtcH(4)), and 3,3',4,4'-biphenyltetracarboxylate acid (3,3',4,4'-bptcH(4)) with corresponding metal salts under hydro/solvothermal conditions, respectively. Complexes 1-3 have entangled structures with different topologies: 1 is a 3-fold interpenetrating NbO three-dimensional (3D) network; 2 is a 3-fold interpenetrating dmp 3D net; 3 is a 6-fold interpenetrating dia 3D chiral net containing rare 1D helical chains with the same handedness. Complex 4 is an uninodal 6-connected network with a Sch?fli symbol of (4(8)6(4)8(3)) based on the trinuclear Ni(II) subunits, while complexes 5 and 6 are 1D chains. Interestingly, compound 6 represents the rare example of MOFs that exhibit high photocatalytic activity for dye degradation under visible light and shows good stability towards photocatalysis. Complexes 3 and 6 exhibit intense blue emissions in the solid state at room temperature whereas 3 appears to be a good candidate of novel hybrid inorganic-organic NLO material.     

Viscosity and Structure of Melts of H Complexes of Acid Diesters of Aromatic Tetracarboxylic Acids with Aromatic Diamines

The viscosity, lifetime, and structure of melts of supramolecular H-bonded complexes of acid diethyl and dimethyl esters of 3,3',4,4'-(diphenyl oxide)tetracarboxylic or 3,3',4,4'-diphenyltetracarboxylic acids with aromatic diamines (diaminodiphenylmethane or m-phenylenediamine) are studied.     

Synthesis and characterization of photosensitive polyimides from methylthiomethyl-substituted 4,4′-diaminodiphenylmethanes and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride

A series of novel polyimides are synthesized by the reaction of 3,3′,4,4′-benzophenonete-tracarboxylic dianhydride (BTDA) with four methylthiomethyl-substituted aromatic diamines: 3-methylthiomethyl-4,4′-diaminodiphenylmethane ( I ), 3,3′-dimethylthiomethyl-4,4′-diaminodiphenylmethane ( II ), 3,3′,5-trimethylthiomethyl-4,4′-diaminodiphenylmethane ( III ), and 3,3′,5,5′-tetramethylthiomethyl-4,4′-diaminodiphenylmethane ( IV ) in refluxing m-cresol. The polyimide of diamine I and BTDA carrying only one pendant methylthiomethyl group in a repeating unit is readily soluble in m-cresol, chloroform, and polar aprotic solvents. Increasing the number of the pendant group results in higher solubility. These fully imidized polyimides are also intrinsically photosensitive. The fraction of photoreactive benzophenone sites that relates to the rate and degree of completion of photocrosslinking reaction increases systematically with the increase of the pendant group content. As the average number of the pendant group in a repeating unit reaches 3, 63% of benzophenone sites are found to be photoreactive. These methylthiomethyl-substituted polyimides possess moderate tensile strength which falls in the range of 67–81 MPa. As a result of the increase of methylthiomethyl content, this type of polyimide reveals higher glass transition temperature but lower thermal stability due to the considerable dimension of the pendant group and the ready cleavage nature of the C? S bond. © 1993 John Wiley & Sons, Inc.     

Effects of structure on properties of some new aromatic-aliphatic polybenzimidazoles

Polybenzimidazoles were prepared in poly(phosphoric acid) from isophthalic, m- and p-phenylene diacetic, succinic, adipic, suberic, and sebacic acids and 3,3′-diaminobenzidine, 3,3′,4,4′-tetraaminodiphenyl ether and 3,3′,4,4′-tetraaminodiphenylmethane. The thermal, mechanical, and bonding properties were studied. A 3:1 copolymer of isophthalic and m-phenylenediacetic acid with 3,3′-diaminobenzidine showed the best results as far as isothermal oxidation resistance and thermal and processing characteristics.     

Antimicrobial and antispasmodic tetrahydroanthracenes from Cassia singueana

Four tetrahydroanthracene derivatives with antimicrobial and antispasmodic activities have been isolated from Cassia singueana. The evidence described in the following indicates them to be torosachrysone (1), germichrysone (4), and two new dimeric tetrahydroanthracenes, singueanol-I (7) or 6,6′-dimethoxy-3, 3′,8,8′,9,9′-hexahydroxy-3,3′,7,7′-tetramethyl-3,3′,4,4′-tetrahydro(10,10′-bianthracen)-1,1′(2H,2′H)-dione, and singueanol-II (8) or 6,6′-dimethoxy-3,3′,8,8′,9,9′-hexahydroxy-3,3′,7,7′-tetramethyl-3,3′,4,4′-tetrahydro(5,10′-bianthracen)- 1′(2H,2′H)-dione.     

一种用于质子交换膜材料的磺化聚醚醚砜的合成

以发烟硫酸和4,4′-二氯二苯砜为原料,通过磺化反应,制得磺化二氯二苯砜,然后利用亲核缩聚反应,调整磺化单体和非磺化单体的比例,与四甲基联苯二酚进行聚合,制取了系列具有不同磺化度的聚醚醚砜,并对聚合物的结构进行了研究.     

Low pH hydrothermal synthesis and properties of lanthanide-organic frameworks with (4(10),6(5))(4(9),6(6)) topology constructed from Ln-Hbptc building blocks

Two novel lanthanide-organic frameworks (LnOFs) with (4(10),6(5))(4(9),6(6)) topology, [Ln(Hbptc)(H(2)O)](n) (Ln = Eu(1), Gd(2); H(4)bptc = 3,3',4,4'-biphenyltetracarboxylic acid) were synthesized via the hydrothermal in situ reaction between lanthanide salts and 3,3',4,4'-biphenyltetracarboxylic dianhydride (bpta) under low pH conditions. In complexes 1 and 2, homohelix bundles with opposite chirality are assembled alternately and result in pillar-like 3D extended networks incorporated with coordinated water molecules, which show high thermal stability. The luminescence properties are illustrated by the Eu(III) complex (1) and its Gd-doped compound, which are intensive red emitters. The magnetic properties of complexes 1 and 2 are also investigated.     

Hepatoprotective compounds from Canarium album and Euphorbia nematocypha

Successive purification of the extract from Canarium album and Euphorbia nematocypha, guided by antihepatotoxic activity in primary cultured rat hepatocytes, led to the isolation of brevifolin (1), hyperin (2), ellagic acid (3) and 3,3'-di-O-methylellagic acid (4) as hepatoprotective compounds. Compounds 1,3 and 4 also reduced carbon tetrachloride (CCl4)-induced liver damage in mice. The hepatoprotective activities of 1, 2, 3 and 4 in vitro and in vivo are apparently due to their antioxidative effects, which were exhibited by further studies using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and CCl4-induced lipid peroxidation systems.     

(mu-L)[RuII(acac)2]2]n, n= 2+, +, 0, -, 2-, with L = 3,3',4,4'-tetraimino-3,3',4,4'-tetrahydrobiphenyl. EPR-supported assignment of NIR absorptions for the paramagnetic intermediates

A complete EPR and UV-Vis-NIR spectroelectrochemical characterisation has been carried out for the series 1(2+/+/0/-/2-) where is the 1 new complex [(mu-L)[Ru(II)(acac)2]2], L = 3,3',4,4'-tetraimino-3,3',4,4'-tetrahydrobiphenyl. The paramagnetic intermediates are identified as the anion radical (L*-) complex 1*- with a long-wavelength intra-ligand transition at 2160 nm and as the weakly coupled diruthenium(II,III) species 1+ (Kc= 10(3)) with a low-intensity intervalence charge transfer (IVCT) band at 1570 nm. DFT calculations using ADF and Gaussian 03 programs support these assignments.     

Structure elucidation and NMR spectral assignments of three new lignan glycosides from Akebia trifoliata

Three new lignan glycosides (1-3) were isolated from the stems of Akebia trifoliata. Their structures were elucidated as (7R,8R,7'R,8'R)3,3',5,5'tetramethoxy-4,4'dihydroxy-7,9':7',9-diepoxylignan-4-O-beta-D-glucopyranoside (1), (7S,8S,8'R)-4,4',9-trihydroxy-3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (2), (7R,8R,8'S)-4,4',9-trihydroxy3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (3) by spectral analyses, primarily NMR, MS and CD. The NMR assignments for the compounds were carried out using 1H, 13C, DEPT, COSY, HSQC, HMBC and ROESY NMR experiments.