Microwave assisted synthesis of some new heterocyclic spiro-derivatives with potential antimicrobial and antioxidant activity

Homophthalic anhydride reacts with different aromatic amines to produce N-substituted homophthalimides. Bromination of the latter produces 4,4-dibromo-homophthalimide derivatives that can be used as precursors for spiro-derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiro-isoquinoline derivatives. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro-derivatives. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, 1H-NMR and 13C-NMR. The newly synthesized compounds were tested for their antimicrobial and antioxidant activities, showing weak or no antimicrobial activity. On the other hand select compounds showed promising antioxidant activities.     

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and dibenzothiophene units in the backbone

New bis(α-diketones) containing thiophene and dibenzothiophene groups were synthesized. Via the reaction of these monomers with aromatic tetramines under high-temperature polycondensation conditions, a series of new polyphenylquinoxalines combining high thermal and mechanical characteristics with solubility in organic solvents were prepared. Polyphenylquinoxalines exhibit intense fluorescence in solution and in thin films with maxima in the region of 432–522 and 450–530 nm in the case of thiophene-containing and dibenzothiophene derivatives, respectively.     

Star-like fluorene based polyamines: non-conjugated building blocks for light-harvesting materials

We report herein a series of novel tetramines (2-6) built using the fluorene core. The design features a diamine conjugated by a fluorene core and two non-conjugated triarylamines dangling through the bridge methine moiety. These polyamines are amorphous in nature and display moderate emission properties that are either dependent on the nature of the arylamine segments or reminescent of the fluorene backbone. The phenyl, naphthyl, fluorenyl and carbazolyl amine based materials are blue emissive while the pyrenylamine based compound emits yellow-green color. We demonstrate a possibility of using blue-emitting fluorene derivatives (2 and 4) blended with poly(N-vinylcarbazole) (PVK) to fabricate organic light emitting diodes (OLEDs). Emissions in the EL devices purely originated from the fluorene derivatives alone (blue) are contaminated with those of complex species (electromer/electroplex) formed by intermolecular interactions.     

Aromatic polyethers,polysulfones, and polyketones as laminating resins. V. Polymers containing acetylenic side groups

1,3-Bis(p-phenoxybenzenesulfonyl)benzene and 4,4′-diphenoxydiphenyl sulfone were polymerized with isophthaloyl and terephthaloyl chloride in Friedel-Crafts type polymerizations. These polymers had 2,4-diphenoxyacetophenone in the backbone. The acetyl group was then converted into an acetylene group. They were crosslinked effectively by cyclization of the acetylene groups with a catalyst or by cyclo-addition with bisnitrile oxides.     

Arylation of nitromethane with sterically hindered aryl halides

Efficient conditions for Pd-catalyzed cross-coupling of sterically hindered aryl halides with nitromethane were developed to give corresponding aryl nitromethanes. The opportunity to carry out the reaction of polynitromethylation under these conditions was demonstrated, as well as to use the obtained products in the synthesis of bisnitrile oxides.

     

Reductive Heck cyclization versus δ-carbon elimination/decarboxylation: synthesis of dihydroindole and indoles from Baylis-Hillman adducts

Modified Baylis-Hillman adducts having 2-bromoaniline moiety at the primary position underwent Pd-mediated reductive Heck type cyclization to produce dihydroindole derivatives. The same starting materials can also be used for the synthesis of indole derivatives under slightly different conditions via the concomitant δ-carbon elimination and decarboxylation process.     

Benzo[1,2,5]selenadiazole bridged amines: electro-optical properties

New diamines and tetramines bridged by a low band gap rendering chromophore benzo[1,2,5]selenadiazole were synthesized by following palladium-catalyzed methodologies developed by Hartwig, Stille, or Suzuki. These donor-acceptor compounds display unique absorption and emission characteristics, which are dependent on the strength of the donors.     

Does a Reinforced Kinetic Macrocyclic Effect Exist? The Demetallation in Strong Acid of Copper(II) Complexes with Open and Cyclic Tetramines Containing a Piperazine Fragment

The demetallation in acidic solution of the Cu(II) complexes with open-chain and cyclic tetramines containing a piperazine unit (2 and 3) has been investigated in terms of its kinetic aspects and compared with the behaviour of unsubstituted counterparts (tetramines 1 and 4). The presence of the piperazine fragment slows demetallation of the open-chain-ligand complex owing to the activation barrier associated with the conformational change from boat-to-half-boat; however, it does not affect the demetallation of the macrocyclic complex, which involves the spontaneous boat-to-twist conformational change. Thus, lateral reinforcement of a cyclam-like ligand does not add any further contribution to the typical inertness in demetallation of macrocyclic complexes.     

Examination of the diphenylpropanoids of nutmeg as their trimethylsilyl, triethylsilyl and tri-n-propylsilyl derivatives using combined gas chromatography and mass spectrometry.

Ethyl acetate extracts of thirteen samples of nutmeg and one sample of mace were examined as trimethylsilyl and tri-n-propylsilyl derivatives by gas chromatography and mass spectrometry. Eleven compounds derived from two types of diphenylpropanoid were identified; the relative proportions and quantities of these compounds varied considerably in the different samples. Single ion chromatograms were used to obtain the relative concentration of one series of compounds. Preparation of the triethylsilyl and tri-n-propylsilyl derivatives resulted in greatly increased separation of the diphenylpropanoids over trimethylsilyl derivatives, which tended to produce a group of compounds with many unresolved peaks.     

Synthesis and in vitro behavior of iron-crosslinked N-methyl and N-benzyl hydroxamated derivatives of alginic acid as controlled release carriers

N-methyl and N-benzyl hydroxylamines were synthetically conjugated to alginic acid to produce hydroxamated derivatives with different degrees of substitution. The new polymeric materials were used to form coordinate complexes with iron(III). The hydroxamated derivatives as well as their iron complexes were characterized using infrared spectroscopy and differential scanning calorimetry.Phenobarbitone-loaded and blank beads were prepared utilizing the new iron-crosslinked hydroxamated polymers and evaluated with respect to their ability to control drug release, as well as their iron leaching properties.The iron-crosslinked polymeric composites proved capable of encapsulating the model drug and sustaining its release in the dissolution media, the release profiles were sensitive to the type and degree of substitution.     

新型溴乙酰四胺化合物的合成

以四胺盐酸盐和2-溴乙酰溴为起始原料,在碳酸钾和二氯甲烷/水中通过缩合反应合成了两个新型溴乙酰四胺化合物,其结构经1H NMR和MS表征.     

Effects of substituents on the chlorination of methyl 3-hydroxythiophene-2-carboxylate and on the reaction of the resulting chlorinated products with active hydrogen containing compounds

The title tandem reactions that produce 5-substituted compounds of methyl 3-hydroxythiophene-2-carboxylate can also be applied with a minor modification to the 4-alkyl and 4-aryl derivatives thereof. On the other hand, 5-alkyl and 5-aryl derivatives that undergo a similar smooth chlorination behave in the second reaction in a different manner.     

Phthalocyanine polymers. IV. Novel type of thermally stable polyimides derived from metal phthalocyanine tetramines and benzophenone tetracarboxylic dianhydride

Poly(metal phthalocyanine)imides of copper, cobalt, nickel, and zinc were synthesized by the reaction of metal phthalocyanino tetramines with benzophenone tetracarboxylic dianhydride. These polymers were characterized by elemental analyses and IR, TGA, and inherent viscosity studies. Noteworthy features of these phthalocyanine polymers are their remarkable thermal and thermooxidative stabilities with char yields at 800°C that range from 78 to 83% in a nitrogen atmosphere. The relative thermal stabilities of these polymers have been evaluated by activation energy measurements.     

Bisorthoesters as polymer intermediates. II. A facile method for the preparation of polybenzimidazoles

Aromatic bisorthoesters were found to be good polymer intermediates and could be condensed with aromatic tetramines under mild conditions, in DMSO at 100°C in a relatively short reaction time to give polybenzimidazoles. The hexapropyl orthoesters of terephthalic and isophthalic acid were the preferred aromatic orthoesters because they were relatively easily purified by vacuum distillation to polymer grade intermediates, since they are liquids. Higher orthoesters distill even under good vacuum near or above the decomposition temperature of the orthoester group. Hexaethyl orthooxalate was also used and is a very useful and stable derivative of oxalic acid, which can be used for condensation reactions. These three orthoesters were used for condensations with 3,3′,4,4′-tetraaminobiphenyl, 1,2,3,4-tetraaminobenzene, 3,3′,4,4′-tetraaminobiphenyl ether, and 3,3′,4,4′-tetraaminobenzophenone. All polybenzimidazoles were obtained in high to quantitative yields and with varying molecular weights (η_inh = 0.1?0.8 dl/g), which in some cases were in the fiber forming range.     

Synthesis and photophysical properties of polyphenylquinoxalines with thiophene and benzothiophene units in side chains

New bis(α-diketones) with thiophene and benzothiophene moieties were synthesized. A series of new polyphenylquinoxalines containing these moieties in side chains was prepared via polycondensation of these diketones with different aromatic tetramines. The polymers are soluble in a variety of organic solvents, and their solutions form transparent films having a tensile strength of σ = 80–100 MPa and an elongation at break of ? = 5–12%. The polymers exhibit fluorescence in solution in trifluoroacetic acid and in films with a maximum at 430–570 and 460–480 nm. The 10% mass loss temperature in air ranges within 440–490°C.     

Poly(diacetylene)-nanofibers can be fabricated through photo-irradiation using natural polysaccharide schizophyllan as a one-dimensional mold

Schizophyllan interacts with various 1,4-diphenylbutadiyne derivatives to induce their chirally-twisted packing. A series of referential experiments using other polysaccharides (amylose, pullulan, dextran, etc.) and a carbohydrate-appended detergent (dodecyl-beta-d-glucopyranoside) indicates that these 1,4-diphenylbutadiyne derivatives are accommodated within a tubular cavity constructed by a helical superstructure of schizophyllan. In these 1,4-diphenylbutadiyne derivatives, 1,4-bis(p-propionamidophenyl)butadiyne can be easily polymerized through UV-irradiation, in which schizophyllan acts as a one-dimensional mold to produce the corresponding poly(diacetylene)s with fibrous morphologies. Detailed investigations on this unique approach to prepare the nanofibers revealed that it includes two individual processes, that is, 1) UV-mediated polymerization of encapsulated 1,4-bis(p-propionamidophenyl)butadiyne to produce immature nanofibers and 2) their reorganization through hydrophobic interfiber interactions into ordered nanofibers. The other 1,4-diphenylbutadiyne derivatives could not be polymerized through UV-irradiation, indicating that the p-propionamido-functionalities play substantial roles for a suitable packing of the monomer for the polymerization. The other 1,4-diphenylbutadiyne derivatives, however, can be also polymerized through gamma-ray irradiation in the presence of schizophyllan to give the corresponding poly(diacetylene)-nanofibers, emphasizing the wide applicability of the schizophyllan-based strategy for polymerization of various 1,4-diphenylbutadiyne derivatives.     

Pd catalyzed coupling of 1,2-dibromoarenes and anilines: formation of N,N-diaryl-o-phenylenediamines

1,2-Dibromoarenes were coupled with aniline derivatives to yield N,N-diaryl-o-phenylenediamines in moderate to good yield using a palladium/phosphine or palladium/carbene catalyst system. Under similar conditions, 1,2,4,5-tetrabromobenzene was coupled with aniline derivatives to produce the corresponding tetrasubstituted derivatives which are oxidized on workup to yield azophenines. The sequential reaction of two different anilines with 1-chloro-2-iodobenzene afforded mixed N,N-diaryl-o-phenylenediamines.     

Design and synthesis of two epoxide derivatives from 3-ethynylaniline

For several years ago, several epoxide derivatives have been prepared using different methods; however, some protocols use reagents which could be expensive and require specials conditions. The aim of this investigation was to prepare two new epoxide-derivatives from 3-ethynylaniline using some reactions such as oximation, acetylation, 2 + 2 addition, functionalized chloroamides, and epoxidation via Darzens reaction. The chemical characteristics of epoxide derivatives were determinate through a spectroscopic and spectrometric analysis. In conclusion, it is noteworthy that the reactions used in this study do not involve expensive reagents or special conditions for the synthesis of epoxide derivatives.     

A new eco-friendly strategy for the synthesis of novel antimicrobial spiro-oxindole derivatives via supramolecular catalysis

Novel spiro-oxindole derivatives were synthesised by one-pot multicomponent reaction using isatins, urea and 1,3-dicarbonyls. β-Cyclodextrin, an oligosaccharide, catalysed the reaction and can be reused for further reaction after recovery. This developed synthetic route is environmentally benign in which water is used as solvent to produce excellent yields of products. The synthesised compounds were evaluated for their antimicrobial activities against two bacteria and two fungi. All the synthesised spiro-oxindoles exhibit significant antimicrobial activity.