Preparation of new heterotopic ligands

A six-step synthesis of two new heterotopic ligands, each possessing two unusual N,N,N,O tetradentate binding subunits, has been developed. This work presents a particularly facile and rapid synthetic protocol for the preparation of these ligands, which one expected to act as useful components in inorganic self-assembly for the preparation of various types of complexes.     

Preparation of some new polybenzimidazoquinazolines

Several new types of polybenzimidazoquinazolines with a different recurring unit have been prepared by solution polycondensation in polyphosphoric acid followed by heating at elevated temperature under reduced pressure. The polymers thus obtained were light yellow to brown powdery materials hardly soluble in common organic solvents and soluble in concentrated sulfuric acid. The inherent viscosity of the polymers ranged from 0.1 to 0.58 and showed good thermal stability.     

Preparation of new quinolinecarbohydroxamic acids

A series of new quinolinecarbohydroxamic acids has been prepared by treatment of corresponding methyl quinolinecarboxylates with hydroxylamine.     

Preparation of new 1,2,4-triazines

Several 1,2,4-triazines were synthesized. ¹³C- and ¹⁵N-nmr spectroscopy was employed for structure determination.     

Preparation of some new coumarin dyes

Series of coumarins containing heterocyclic substituent in 3-position were prepared. Sulfonyl chloride, a reactive group, was drawn into the heterocycle, and further condensed with amines to give series of new compounds that contain N-alkyl sulfamide. The spectral properties and dyeing character of these new dyes are discussed. A bathochromic shift (10 nm), enhanced fastness in light and sublimation (1-2 grade) and larger molar extinction coefficient (increase 104 L ·mol-1 ·cm-1) are apparent with these new compounds. In the meantime, larger solubility appears with these new compounds.     

Preparation of new reactive methylene monomers

Acryloylacetone, methacryloylacetone, and related monomers have been synthesized by using cyclopentadiene as a blocking agent during the Claisen condensation.     

Preparation of new modified catalyst carriers

Novel modified catalyst carriers have been prepared. First, aminopropyltriethoxysilane (APTES) was immobilized on the silica surface by using the saturated gas–solid reactions. Secondly, two different (tetramethylcyclopentadienyl)chlorosilanes, (Me₂Si(C₅Me₄H)Cl and MeHSi(C₅Me₄H)Cl), were synthesized and anchored on the amine surface using liquid-phase reactions. Characterization of these stepwise prepared surfaces was carried out by ¹H, ¹³C and ²⁹Si solid state NMR and FTIR spectroscopy.     

Preparation of new types of temperature-responsive cellulose derivatives

This paper reviews briefly our preliminary results concerning thermoplastic hydrogels and thermotropic aqueous gels from cellulose. Several kinds of thermoplastic hydrogels and thermotropic aqueous gels were prepared from cellulose and their thermal properties were examined. The former aims at preparing water-insoluble cellulose derivatives having a high water absorbency and a thermal flow temperature of approximately 130°C, while the later aims at preparing water-soluble cellulose derivatives which show a solubility behavior similar to that of synthetic polymers with a lower critical solution temperature (LCST) in aqueous solution. The results will be discussed in terms of the chemical structure of the prepared derivatives and their substituent distributions along the cellulose chain.     

Preparation of new polyether with oxetane pendant group

A new oxetane-containing polyether was synthesized by polycondensation of bisphenol-AF (BPAF) with 3,3-bis(chloromethyl)oxetane (BCMO) using the phase-transfer catalyzed method. The polycondensation proceeded very smoothly in aromatic solvents, catalyzed by quaternary ammonium or phosphonium salts, such as tetrabutylammonium bromide (TBAB) and tetrabutylphosphonium bromide (TBPB), to afford the polymer with high yield and molecular weight. Further, a polymer with relatively high molecular weight was obtained when the reactions were carried out in aromatic and lipophilic solvents such as benzene and nitrobenzene. The modification of this oxetane-containing polyether was easily achieved by carrying out ring-opening of the oxetane ring by using hydrogen chloride in methylene chloride, which produced a functional polymer containing hydroxyl and chloro groups. The oxetane-containing polyether was observed to be soluble in chlorinated aliphatic hydrocarbons such as methylene chloride and chloroform, as well as polar solvents such as DMSO, DMF, and DMAc, and also some common organic solvents such as benzene and toluene. However, it was insoluble in both aliphatic hydrocarbons as well as alcoholic solvents. The oxetane-containing polyether was observed to start losing weight at around 300°C under nitrogen atmosphere, and 10% weight loss was measured to be 411°C. The glass transition temperature of the oxetane-containing polyether was measured to be 134°C and the wide-angle X-ray diffraction pattern revealed this polymer to be semicrystalline. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 103–107, 1998     

Preparation and characterization of new mouldable cellulose-AESO biocomposites

A new concept of using acrylated epoxidized soybean oil (AESO) in the production of 3D cellulose biocomposites was evaluated. Cellulose-AESO composites were prepared by dissolving pulp in N,N-dimethylacetamide/lithium chloride and adding AESO and an initiator to the solutions followed by thermal curing and compression moulding at room temperature. The resulting biocomposites were characterized by FE-SEM, FT-IR, XRD, GC, TGA and nano- and microindentation. SEM images indicated the presence of spherical morphology and FT-IR together with TGA results showed no hydrogen or covalent bonding between the two components. The existence of hydrophobic interactions between AESO molecules and cellulose hydrophobic domains was proposed. AESO aggregates captured and covered by cellulose chains increase the flexibility of the composites acting as specific plasticizer and after polymerization introduce strength to the material. It was found that the optimal amount of AESO for achieving both desired hardness and good mouldability should be below 20 %.     

Preparation and properties of new bilirubin matrix standards

Summary The development of universal stable bilirubin standards in human serum albumin is described. The importance of the use of bilirubin of the best available quality and in human serum albumin is stressed. The preparation of the standards should take place under strict darkroom conditions and for large batches also in the cold. The stabilities of the lyophilized and reconstituted standards is good and there is no loss of bilirubin during the preparation. A 100% recovery of weighed-in bilirubin is obtained.

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Herstellung und Eigenschaften von neuen Bilirubin-Matrixstandards

     

Preparation of new blocked diisocyanate for dental application

A novel two-stage method of preparing 2-hydroxyethyl methacrylate (HEMA) and methoxyphenol or cholorophenol blocked 2,4-tolylene diisocyanate (TDI) was devised. The first stage reaction of TDI with HEMA was carried out in petroleum ether heterogeneously with the precipitation of the intermediate product, monoadduct, in the reaction solution, and followed by a second stage homogeneous reaction of monoadduct with the blocking agent, chlorophenol, or methoxyphenol, in ethyl acetate. In both reactions the inhibitor, chloranil, and the catalyst, dibutyltin dilaurate, were used. A total of eight products were achieved. Results of elemental analyses of these products along with their LC chromatograms, NMR, and IR spectra indicated that these materials were indeed the compounds expected. Testing results of these materials as dental adhesives will be reported in a separate paper.     

Preparation and characterization of new cycloplatinated carbene complexes

Reaction of iodotrimethylplatinum(IV) tetramer with bis(1,3-diphenyl-2-imidazolidinylidene) [(Hdpim)₂] gave a new dinuclear carbene complex, [{Pt(dpim)I}₂](dpim  1,3-diphenyl-2-imidazolidinylidenato-2-C,2′-C), III, in 84% yield, which contains a cycloplatinated carbene structure. Some mononuclear derivatives, [Pt(dpim)(acac)], [Pt(dpim)I{P(OCHMe₂)₃}], [Pt(dpim)-(NCCH₃)₂]ClO₄, and [Pt(dpim)(COD)]ClO₄ were prepared from III and characterized by means of elemental analysis, IR and NMR spectroscopy, and molar conductivity. An intermediate species, [{PtMeI(Hdpim)}₂], leading to III is discussed also.     

Preparation and characterization of new micelle-forming cholesterol amphiphiles

New sulfated and sulfonated cholesterol amphiphiles were synthesized and characterized by dynamic light scattering and electron microscopy. The surfactants form micelles with diameters up to 30 nm. Their critical micelle concentration values were determined by conductometry and photometric measurements. Use of the new amphiphiles enables the transfer of an asymmetric hydrogenation reaction into aqueous solution by keeping the activity and increasing the enantioselectivity. Interesting liquid-crystalline behaviour was observed. Received: 7 July 1999 /Accepted in revised form: 5 November 1999