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71.
Ito S Kanazawa M Munakata K Kuroda J Okumura Y Nozaki K 《Journal of the American Chemical Society》2011,133(5):1232-1235
Coordination-insertion copolymerization of allyl monomers with ethylene was developed by using a palladium/phosphine-sulfonate catalyst. A variety of allyl monomers, including allyl acetate, allyl alcohol, protected allylamines, and allyl halides, were copolymerized with ethylene to form highly linear copolymers that possess in-chain -CH(2)CH(CH(2)FG)- units. 相似文献
72.
Sulfoxides are reduced by a combination of sodium borohydride, a catalytic amount of cobalt(II) chloride hexahydrate, and chromatographic neutral alumina preloaded with a small amount of water (moist alumina) in hexane to produce the corresponding sulfides in good to excellent yields under mild conditions. An interesting structural influence of sulfoxides on their reactivity is observed.
73.
Synthesis of deaminocolchinyl methyl ether 9 was achieved from tetramethoxy-substituted biphenyl-2-carb-aldehyde 12 via tricyclic ketone 20 and 5,6-didehydro congener 11 . Compound 9 was identical in every respect with material prepared from colchicine via 6,7-didehydro congener 10 . Measuring inhibition of tubulin polymerization in vitro showed compounds 4 , 5 , and 9 – 11 of the alloseries of colchicinoids to be particularly potent inhibitors. 相似文献
74.
Te(IV) can be separated from Te(VI), Se(IV) and Se(VI) by adsorption of Te(IV) on a DEAE-cellulose column from a mixed 1M hydrochloric acid-acetic acid solution (1:9, v/v). This allows a selective separation of Te (IV) from the other three species in widely different mole ratios. 相似文献
75.
Preparation of poly(phosphate ester)s having bisphenol moieties as mesogenic units in the main chain
Kazuo Sugiyama Koji Makino Masao Morita Yoshikuni Yoshimitsu 《Journal of polymer science. Part A, Polymer chemistry》1994,32(11):2119-2126
Poly(phosphate ester)s, PPE 1a–d , were synthesized from polycondensation of methyl phosphorodichloridate (MPDC) with various bisphenols such as 4,4′-biphenol 1a , 4,4′-dihydroxyphenylether 1b , bis(4-hydroxyphenyl)methane 1c , and 3,3′-dimethyl-4,4′-dihy-droxybiphenyl 1d . PPE 2a–d with hexamethylene spacers were also obtained from poly-condensation of MPDC with 4,4′-bis(6-hydroxyhexyloxy)biphenyl 2a , 4,4′-di(6-hydroxyhexyloxy)phenyl ether 2b , bis[4-(6-hydroxyhexyloxy)phenyl]methane 2c , and 3,3′-dimethyl 4,4′-di(6-hydroxyhexyloxy)biphenyl 2d . The degree of crystallinity of PPE 1a–1d without hexamethylene spacer was 3.3–17.6%, whereas PPE 2a and PPE 2b which exhibit mesomorphic behavior were 20.1 and 18.6%, respectively. PPE 2a and PPE 2b show the mesophase at 139.6–195.5°C and 42.4–66.3°C, respectively. PPE 2c and PPE 2d were obtained as rubbery. From pyrolysis of PPE in air the temperature corresponding to 5% weight loss was found to be 322–408°C and 284–291°C for PPE 1 and PPE 2 , respectively. It was also found that PPE 2a was enzymatically degraded by phospholipase C. © 1994 John Wiley & Sons, Inc. 相似文献
76.
Yoshikuni N 《Talanta》1994,41(1):89-92
Heterocyclic ring compounds containing nitrogennitrogen bonds such as 1H-1,2,4 triazole, 2,4,6 trimethylbenzenesulfonyltriazolide and pyridazine can be completely decomposed in the molten state with mixtures of various ratios of concentrated sulphuric acid and lithium sulphate (molten ALS) flux containing a catalyst such as silver sulphate. The quantitative recovery of nitrogen in the above three compounds with the molten ALS flux decomposition system can be obtained by the Kjeldahl method. 相似文献
77.
IPN-type composites consisting of cellulose acetate (CA) and poly(methyl methacrylate; PMMA) were successfully synthesized
in film form. In this synthesis, a mercapto group (SH)-containing CA, CA-MA, was prepared in advance by esterification of
CA with mercaptoacetic acid, and then intercomponent cross-linking between CA-MA and PMMA was attained by thiol–ene polymerization
of methyl methacrylate (MMA) onto the CA-MA substrate. For comparison, polymer synthesis was also attempted to produce a semi-IPN
type of composites comprising CA and cross-linked PMMA, via copolymerization of MMA and ethylene glycol dimethacrylate as
cross-linker in a homogeneous system containing CA solute. Thermal and mechanical properties of thus obtained polymer composites
were investigated by differential scanning calorimetry, dynamic mechanical analysis, and a tensile test, in correlation with
the mixing state of the essentially immiscible cellulosic and methacrylate polymer components. It was shown that the specific
IPN technique using thiol–ene reactions usually resulted in a much better compatibility-enhanced polymer composite, which
exhibited a higher tensile strength and even an outstanding ductility without parallel in any film sample of CA, PMMA, and
their physical blends. 相似文献
78.
Regioselective and high-yielding nuclear monobromination of aromatic ethers can be accomplished with a combination of NaClO2, NaBr, and Mn(acac)3 catalyst in dichloromethane under mild and neutral conditions with the aid of Montmorillonite K10. 相似文献
79.
80.