Synthesis of phosphorus-containing poly-o-acylamideoximes from polyacrylonitrile

The synthesis of phosphorus-containing poly-O-acylamideoximes from polyacrylonitrile has been accomplished by the reaction sequence: Reaction is believed to occur at the NH₂ nitrogen as well as at the oxime group, but reaction is not believed to occur at both groups in the amide oxime unit. Inclusion of the phosphorus moiety occurs in the medium to high range.     

Oxazolidines versus schiff bases

The formation of oxazolidines from propionaldehyde and aliphatic β-aminoalcohols is complicated by the appearance of appreciable amounts of unsaturated Schiff bases. The simple Schiff base, often the dominant species when aromatic aldehydes react with amines, could not be detected in the present aliphatic systems. We conclude that in aliphatic systems the order of stability is and . The gem-dimethyl group α to nitrogen stablizes the heterocyclic ring remarkably.     

Fragmentations of protonated acetophenones via intermediate ion–molecule complexes

Protonated acetophenones, substituted with a methoxymethyl group in the para and meta positions, have been generated by electron impact induced fragmentation of the correspondingly substituted 2-phenylpropan-2-ols. The metastable ions, formed in the second field-free region of a VG ZAb 2F mass spectrometer, react unimolecularly by elimination of CH₃OH, formation of CH₃CO⁺ and ions, loss of CH₃COOCH₃, and loss of CH₂O. The mechanisms of these fragmentations have been elucidated with the aid of deuterated analogues of the protonated acetophenones. It is shown that these reactions are initiated by an endothermic transfer of the proton at the carbonyl group of the protonated acetophenones to the benzene ring. A further migration of the proton to the ether O atom of the methoxymethyl side-chain leads eventually to the elimination of CH₃OH. Protolytic bond cleavages of either side-chain gives rise to the CH₃CO⁺ and ions. At low internal energies both these ions may be trapped by the aromatic neutral fragment in ion-molecule complexes. Reactions within these complexes result in the energetically favourable losses of CH₃COOCH₃ and CH₂O, respectively. With respect to these reactions, the protonated acetophenones behave analogously to the correspondingly substituted and protonated benzaldehydes.     

Metastable decompositions of cyclopentanol ions and [C5H10O]+˙ ions with the oxygen on the first carbon

Ionized cyclopentanol and [C₅H₁₀O]+˙ ions with the oxygen on the first carbon lose methyl, ethylene, ethyl, ethane and water in their metastable decompositions. We show by collisionally activated decompositions of the products that the losses of ethyl form CH₃CH₂C?O⁺, the losses of ethylene form , and the losses of methyl probably yield . Deuterium labeling indicates that ethyl loss from ionized cyclopentanol occurs following α-cleavage of the ring, isomerization to the enol isomer of ionized n-pentanal and subsequent isomerization to the 3-pentanone ion.     

Darstellung und Eigenschaften von Ti-substituierten N-Heterocyclen

Preparation and Properties of Ti-substituted N-Heterocycles The compounds (x = 2 to 6) have been prepared by transamination of Ti(NMe₂)₄ with the heterocyclic amines and have been characterised by elemental analyses and ¹H NMR and IR spectroscopy. The dependence on both x and n of the thermal decomposition has been studied for the series and . The results can be interpreted in terms of the steric strain of the R₂N and substituents. Apart from the piperidido groups none of the ligands exhibit protective group properties comparable to the R₂N groups.     

Enzyme‐Catalyzed Preparation of Aliphatic Polythioester by Direct Polycondensation of Diacid Diester and Dithiol

Summary: Aliphatic dithiol‐diacid type polythioesters were first enzymatically prepared by the direct polycondensation of hexane‐1,6‐dithiol and diacid diesters using the immobilized lipase from Candida antarctica (lipase CA). As a typical example, diethyl sebacate and hexane‐1,6‐dithiol were polymerized using lipase CA in bulk in the presence of molecular sieves 4A to produce the corresponding polythioester with an of 10 200 in 90% yield. Both the melting and crystallization temperatures of the produced polythioesters were higher when compared to those of the corresponding polyoxyesters. A higher molecular weight polythioester was produced using lipase in a two‐step procedure, i.e., cyclization with subsequent ring‐opening polymerization.

Preparation of polythioester and melting temperature of various polythioesters and polyoxyesters.     

Production of radicals in polyoxymethylene by ultraviolet photolysis: An EPR study

Polyoxymethylene (POM) was photolyzed at 2537 and at 3130 Å at ?196°C. The EPR spectra of the radical intermediates were recorded. Photolysis in vacuo produces a small number of radicals, apparently due to the presence of traces of chromophores. Photolysis in oxygen, however, is a type of photo-oxidation. The radicals HCO, , CH₃·, and HOO· were detected and identified as intermediate products of photolysis. Hydrogen atoms and hydroxyl radicals were too reactive (i.e., mobile) at ?196°C to be observed. Alkoxy and alkyl radicals and the POM peroxy radical were probably formed as well but could not be characterized with certainty.     

Vapor‐Based Synthesis of Poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] and Its Use for Biomimetic Surface Modifications

Summary: The vapor‐based synthesis and characterization of a reactive polymer, poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] ( 1 ), have been reported. The reactive polymer coating enables the immobilization of oligosaccharides via the chemoselective aldehyde‐hydrazide coupling reaction.

     

Metal Complexes of 4,7-Dithiadecane-1,10-dicarboxylic Acid and Allied Compounds

Silver and copper(I) complexes can be obtained from CO₂H? (CH₂)_n? S? CH₂? CH₂? S? (CH₂)_n? CO₂H when n = 1, 2, and 3 (I, II and III resp.); the compound with n = 4 (IV) fails to give these complexes. does give a silver and a copper(I) complex, while the isomeric compound again fails to give these complexes. From IV, V, and VI we prepared the corresponding disulfones.     

Synthesis and biological activities of cis and trans 5‐amino‐3‐[(6‐chloro‐3‐pyridyl)methyl]amino‐1‐(5,5‐dimethyl‐2‐oxo‐4‐substitutedphenyl‐1,3,2‐dioxaphosphinan‐2‐yl)‐4‐cyano(ethoxycarbonyl)‐1H‐pyrazoles

A series of novel title compounds have been designed and synthesized by a multi‐step reaction, the stereochemistry of the reaction was investigated, the structures of all compounds prepared have been confirmed by ¹H NMR, IR, EI‐MS spectroscopy and elemental analysis. The crystal structures of cis 6b and trans 6b were determined by single crystal X‐ray diffraction. The results of preliminary bioassay indicate that some compounds possess a certain extent inhibition effect against aphides at the concentration of 250 ppm.     

Modification of poly(vinyl alcohol) through reaction with phosphorus-containing reactants

Crosslinked products of the form: and have been formed from the interfacial condensation of phosphorus diacid halides with poly(vinyl alcohol). Product yield and amounts of phosphorus reactant included in the product increases as the amount of base increases. Product stability in aqueous systems decreases in the order neutral > base > acid.     

Photoinduced Microphase Separation in Block Copolymers: Exploring Shape Incompatibility of Mesogenic Side Groups

Photoinduced microphase separation in block copolymers (BCP) was achieved for the first time, using a rationally designed diblock copolymer composed of two side‐chain liquid crystalline polymers (SCLCP). The miscibility of the two blocks was promoted by the miscibility between the two types of mesognic side groups, while upon UV exposure inducing the trans–cis isomerization of azobenzene mesogens on one SCLCP, the shape incompatibility of bent cis isomers with an ordered liquid crystalline phase drove the separation of the two blocks resulting in a microphase separated morphology. This result shows the perspective of using light to process and organize BCP morphology and related nanostructures in a lithography‐free manner.

     

Synthesis and Conformation of Three‐Dimensionally Ordered Macroporous Syndiotactic Polystyrene and Poly(p‐methyl styrene)

Three‐dimensionally ordered macroporous (3DOM) syndiotactic polystyrene (sPS) and poly(p‐methyl styrene) (sPPMS) are synthesized using silica colloidal crystal templates with varied diameters in the range of 548–214 nm, and the effect of polymerization space on the conformation of the resulting 3DOM polymers is investigated by spectroscopy and thermal analysis. In‐situ polymerizations of styrene and p‐methyl styrene within the silica templates induce the resulting 3DOM polymers with different conformations and packing of chains, which are different from those of bulk polymers prepared in the absence of templates. Polymerizations in restricted silica templates result in un‐helixication of 3DOM sPS chains and helixication of 3DOM sPPMS chains.

     

Forming of Polymer Nanofibers by a Pressurised Gyration Process

A new route consisting of simultaneous centrifugal spinning and solution blowing to form polymer nanofibers is reported. The fiber diameter (60–1000 nm) is shown to be a function of polymer concentration, rotational speed, and working pressure of the processing system. The fiber length is dependent on the rotational speed. The process can deliver 6 kg of fiber per hour and therefore offers mass production capabilities compared with other established polymer nanofiber generation methods such as electrospinning, centrifugal spinning, and blowing.

     

Thermal decomposition of azoethane

The thermal decomposition of azoethane (AE) was studied by detailed product analysis in the temperature and pressure intervals 508–598 K and 2.7–13.3 kPa. Besides the hydrocarbon products, three characteristic and quantitatively important nitrogen-containing compounds were also determined: ethyl-2-butyldiimide, ethanal-diethylhydrazone, and tetraethyl-hydrazine. Apart from the predominant termination reactions of the ethyl radical with itself and with the μ₂ radical, the decomposition is characterized by a very short chain reaction. The measurements led to determination of the following rate constants and rate constant ratios: for the following reactions:      

Study of associated reaction variables in the synthesis of titanium (IV) polyamines and a comparison of synthesis by different techniques

Synthesis of titanium polyamines was accomplished with “inverse” and “normal” interfacial and aqueous solution systems. Yield was independent of the usual reaction parameters for substituents on p-phenylenediamine for the interfacial systems but might be dependent on the particular diffusion rates of the diamines. Yield decreases as the nucleophilicity of the diamine decreases for the aqueous solution systems. Yield is independent of pH, decreases with reduction in reactant concentration and increases with increases in the amine: Cp₂TiCl₂ ratio for both normal interfacial and aqueous solution systems.     

Phenacyl esters of acetic acid derivatives and their application for the synthesis of 2‐oxo‐4‐phenyl‐5‐(phenylhydrazono)‐2,5‐dihydro‐furan‐3‐derivatives

Coupling of various substituted phenacyl acetates 1 and diazonium salts 3 was studied. If the phenacyl acetates were substituted by an electronaceptor group such as CN or COOEt 3‐substituted phenyl‐5‐(phenyl‐hydrazono)‐5H‐furan‐2‐ones 4 were formed. Also synthesis of aza and diaza analogs is described. The compounds were characterized using MS and NMR spectroscopy.     

Synthesis and psychotropic properties of furyl- and thienyl-germatranes

Trihalogermyl-furans and -thiophenes were prepared by inserting germanium dibromide (GeBr₂) generated from the dibromogermane(II) dioxanate complex into the carbon-halogen bond of halo-furans and -thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.