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1.
Photooxygenations of 4-2H-anisole () and o-xylene () by 3-methylpyridazine 2-oxide () or pyridine 1-oxide () were studied in a variety of solvents at varying irradiation temperatures. Remarkable solvent effect on NIH-shift coupled with their hydroxylation processes was observed. 相似文献
2.
The total synthesis of taurospongin A by two new approaches has been achieved where pi-allyltricarbonyliron lactone complexes have been used to control highly stereoselective additions of the nucleophiles to a carbonyl unit located in the side chain of these complexes. 相似文献
3.
Yasuo Saegusa Sakayu Iida Shigeo Nakamura Nguyen Chau Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1984,22(5):1017-1023
Aromatic polythioamide-oxothioxoquinazolines were synthesized by the polycondensation of 2,2′-(m-phenylene)bis-1,3,4-thiadiazoline-5-thione with aromatic bis-o-amino esters. The polymerizations were carried out at 160°C in acidic media such as m-cresol, sulfolane, and polyphosphoric acid to produce polymers with reduced viscosities up to 0.5 dL/g. These polymers were soluble in polar aprotic solvents like N-methyl-2-pyrrolidone and some acidic media including m-cresol. The polythioamide-oxothioxoquinazolines showed relatively good thermal stability with 10% weight loss at 344–394°C in air. 相似文献
4.
5.
The simultaneous ultramicrodetermination of heterogeneous halogens in organic compounds was carried out by the potentiometric titration with 0.002 M silver nitrate after the sample was decomposed by the flask combustion method. In examination of the titration, it was found that clear potential break at the end point was obtained by controlling the delivery speed of the titrant at 0.2 ml/min or slower and the temperature of the solution to be titrated at ca. 10 °C when chloride ion is present. The error due to coprecipitation during the titration and the effect of the mole ratio of heterogeneous halide ions in the sample solution was examined and discussed. The analysis of organic halogen compounds resulted in an error of within 0.4% and standard deviation of less than 0.25%. 相似文献
6.
Reaction of 5-formyl-1,3-dimethyluracil with some active methylene compounds in the presence of base causes novel ring transformations to give the p-hydroxybenzoates and the nicotinate. 相似文献
7.
A new pulse sequence is proposed for the determination of scalar coupling correlation in small- and medium-sized organic compounds. The method uses a combination of the double pulsed field gradient spin-echo (DPFGSE) and the selective population transfer (SPT) techniques and is shown to be useful in the analysis of complex spectra with many overlapped signals. The usefulness of this method in the structural elucidation of natural substances is demonstrated using strychnine and digitoxin as examples. 相似文献
8.
A variety of O-alkylperoxycarbonic acids () were conveniently prepared by utilizing alkyloxycarbonylimidazoles () as their precursors. Epoxidation of alkenes with such peroxy-acids was studied and their reactivities were compared with those of peroxycarboxylic acids. 相似文献
9.
Shigeo Tazuke Kiyoo Shimada Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1969,7(3):879-888
The radical polymerizability of vinylpyridines in the presence of cobaltous chloride was studied in DMF solution, and the results were correlated with the spectroscopic data obtained for methanol solution. In general, the behavior of vinylpyridine complexed with cobaltous chloride is qualitatively the same as that of zinc complexes reported previously. The rates of polymerization were enhanced by the addition of cobaltous chloride when 4-vinylpyridine(4-VP) or 2-methyl-5-vinylpyridine(MVP) was the monomer, whereas the polymerization of 2-vinylpyridine(2-VP) was retarded by cobaltous chloride. The monomer reactivity of all the vinylpyridines was also enhanced by complex formation as studied by copolymerization with styrene. The enhancement of reactivity of 4-VP complexed with cobaltous chloride is somewhat smaller than that of the corresponding zinc complex. 相似文献
10.
Shimizu H Tada N Ikawa R Kume T Sasaki S 《The journal of physical chemistry. B》2005,109(47):22285-22289
Visual observations through a microscope and in situ Raman measurements have been made for single crystalline ethylene hydrate (EH) and binary methane-ethylene hydrate (MEH) at pressures up to 3.7 GPa and room temperature. Both hydrates showed pressure-induced phase transitions at 1.6, 2.0, and 3.0 GPa for EH and at 1.7, 2.1, and 3.3 GPa for MEH. The cubic sI phase of EH and MEH remains stable up to 1.6 and 1.7 GPa, respectively, which are more widely ranging values than the values for the methane hydrate sI phase. In this sI phase of binary MEH, the cage occupancies by methane and ethylene molecules are investigated from Raman spectra. Above P = 3.0 GPa for EH and 3.3 GPa for MEH, they decomposed by associating with the formation of the polyethylene. 相似文献