摘要:

AbstractOxidation of tertiary amines withN‐chloronylon 66 (NCN) was investigated in several organic solvents. NCN was found to oxidizeN,N‐dimethylaniline (DMA) at room temperature to giveN‐methylaniline with 15–50% yield, depending on the solvents used. Oxidation ofN,N‐dimethylbenzylamine (DMBA) gave benzaldehyde with 15–30% yield and a small amount ofN‐methylbenzylamine. A mechanism was discussed. For comparison,N‐chlorosuccinimide, a low molecularN‐chloro‐compound, was also used for oxidat

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800201

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractA series of active β‐alanine 4‐acyl‐2‐nitrophenyl esters with different lengths of alkyl groups was prepared, and their polycondensation was studied in various solvents. The results of the polycondensation of these esters with triethylamine at room temperature show that the conversion and the degree of polycondensation of the resulting poly(β‐alanine)s depend on the chain length of the alkyl groups. No polymer was obtained in both protic and dipolar aprotic solvents such as methanol and DMSO, whereas nonpolar solvents such as diethyl ether, carbon tetrachloride, or benzene were found to be suitable for the polycondensation. The effect of a variety of amines on the polycondensation was examined for β‐alanine 4‐dodecanoyl‐2‐nitrophenyl ester (4e) in di

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800202

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractPartially hydrogenated 1,4‐polybutadiene is degraded into GC‐detectable reaction products after olefin‐metathesis with 4‐octene in the presence of WCI6/(CH3)4Sn. 1,4‐polybutadiene is homogeneously hydrogenated withp‐toluenesulfonohydrazide and serves as copolymer with non‐hydrogenated and hydrogenated repeating units. Hydrogenated sequences up to an undecade are detectable. The experimental monomer sequence length distribution agrees satisfactorily with the theoretical one calculated under the assumption of an ideal statisti

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800203

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

Abstract2‐(1,3‐Dimethyl‐2,6‐dioxo‐2,6‐dihydropurin‐7‐yl)methylsuccinic acid (2a) and 2‐(5‐methyl‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl)methylsuccinic acid (2b) were synthesized via the addition reaction of theophylline and thymine, respectively, to dimethyl methylenesuccinate, followed by hydrolysis of the resulting ester. The dicarboxylic acid derivatives2aand2bwere further converted to their di‐p‐nitrophenyl esters3aand3b, which were allowed to polycondense with diamines such as 1,6‐diaminohexane, 1,2‐diaminoethane, 3‐aminomethylbenzylamine, and piperazine in solutions. The resulting polyamides are white powders with molecular weights in the range of about 2000–6000. TheDPof the polyamides varies with the kind of diamines and solvent used. All polyamides are soluble in DMSO and formic acid, the polyamides deriving from esters3aand3band 1,2‐diaminoet

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800204

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractStyrene isoprene styrene copolymers (SIS) modified by epoxidizing were investigated in order to obtain adhesive materials. Influences of experimental parameters (concentrations, solvents, compositions of SIS) are shown for epoxidation with monoperoxyphtalic acid at a yield of modification lower than 50%.

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800205

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractIt was found that the formation constants (K) of CuX(QPVP)n−(X = ethylenediaminetetraacetate ion (edta) andN‐(2‐hydroxyethyl)ethylenediamine‐N,N′,N′,‐triacetate ion (hedta), QPVP = partially quarternized poly(4‐vinylpyridine)) increase sharply with increasing degree of quarternization (Q) of QPVP. In the Cu(edta)2−/QPVP system.Kvalues are 481.mol−1forQ= 0%, 8701.mol−1, forQ= 25%, and 1,1.103l.mol−1forQ= 61%, in aqueous methanol (volume ratio 1:1) at μ = 0,1 mol.l−1, pH = 8,0. andT= 25°C. In the system CH3Co(dmg)2H2O/QPVP,Kdecreases linearly with increasing degree of quarternization of QPVP fromK= 1,7.103l.mol−1forQ= 0% toK= 95l.mol−1forQ= 61% in aqueous methanol (volume ratio 3:7) at μ = 0,05, pH = 8,0, andT= 25°C. The decrease inKis +scribed to a relatively large decrease in the rate constant of the forward reaction and a small increase

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800206

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractHemiporphyrazine type macroheterocycles with 2,2′‐bi‐1,3‐dithiolylidene (tetrathiafulvalene) units in the polymeric chains (3a–e) were obtained by reaction of 2,2′‐bi‐1,3‐dithiolylidenetetracarbonitrile (tetracyanotetrathiafulvalene) (1) with several diamines (2a–e). The black polymers were characterized by elemental analyses and IR spectra. Thermoanalytic measurements showed that decomposition starts without melting at temperatures>300°C. The polymers were found to be polymeric organic semiconductors with activation energies of 0,6–1,4eV and electrical conductivities in the range from 10−14to 10−10Ω−1.cm−1. In the case of the polymers3aand3bit was possible to obtain metal complexes (4a–b) by substituting the two hydrogen atoms inside the macroheterocyclic rings. Depending on the metal atoms the electrical conductivities were enhan

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800207

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractThe method of gel permeation chromatography was used to study the structural changes of poly(2,6‐dimethyl‐1,4‐phenylene oxide) in the course of thermooxidative degradation. During the degradation two principal processes occur: random scission and crosslinking. The latter process leads to the formation of insoluble fractions. The reaction rates and activation energies of both processes have been determined. The mechanism of degradation as well as the influence of some additives is discussed on the basis of experimental

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800208

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractA series of new catalytic systems ZnEt2/cocatalyst were prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide was studied. The systems ZnEt2/m‐HXC6H4XH (mole ratio 1:1) system (X = NH, S) were chosen to elucidate the influence of the heteroatom on the activity of the catalytic system. The obtained results were discussed in terms of the influence of the basicity of the heteroatom and of its hybridization on the structure and association of the catalyst molecul

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800209

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY

摘要:

AbstractConformational transitions of histones F1 (H1), F2a (H2A), F2b (H2B), and F3 (H3) in the presence of carcinogens 4‐nitroquinoline‐N‐oxide, 13‐H‐dibenzo[c,j]carbazole, and 7‐H‐dibenzo[c,q]carbazole were studied by the circular dichroism (CD) probe. The polypeptide main chain conformation of the very lysine rich histone F1 was not affected by these carcinogens, but the tertiary structure was modified slightly by the carbazoles. The secondary structure of histone F2a was significantly modified by the carbazoles which enhanced the helix content, whereas the effect of the 4‐nitroquinoline‐N‐oxide on the backbone conformation was weak. The tertiary structure of F2a was affected by all three carcinogens, whereby the 7‐H‐dibenzo[c,g]carbazole produced the strongest enhancement of the CD bands assigned to tyrosine and phenylalanine chromophores. Moreover, this carcinogen produced extrinsic Cotton effects in the 300–380nm spectral zone. Similar effects of the carbazoles were observed with histone F2b, although in this case the main chain conformation was changed only slightly. The secondary structure of histone F3 was slightly affected by the carcinogens but the tertiary structure was significantly modified by the carbazoles. The CD bands of F3 which were assigned to the tyrosine and phenylalanine chromophores were most strongly enhanced by the 1

ISSN:0025-116X    

DOI:10.1002/macp.1979.021800210

出版商:Hüthig&Wepf Verlag    

年代:1979

数据来源: WILEY