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991.
David N. Nikogosyan Helmut Grner 《Journal of photochemistry and photobiology. B, Biology》1995,30(2-3):189-193
An investigation of the photochemical properties of glycine, aspartic acid, valine, leucine and methionine was carried out using nanosecond 193 nm laser irradiation and high performance liquid chromatography analysis. The quantum yields of formation of hydrated electrons (Φe−) and decomposition of the substrate (Φd) were determined for the five aliphatic amino acids in neutral aqueous solution at room temperature. From the dependences of Φe− on the laser intensity it follows that the mechanism of photo-ionization is monophotonic (single step). The Φd values under Ar and in the presence of oxygen or N2O are interpreted on the basis of photo-ionization as the dominant process for decomposition of methionine and a significant contribution from photo-ionization in the other cases. A comparison was made between the Φd values (in the presence of oxygen) using irradiation at 193 nm and those from previous measurements at 213 nm. 相似文献
992.
利用气相色谱质谱(GC/MS)电子轰击方法,对6种不同年龄和不同性别的赤鳞鱼肉中的饱和、不饱和脂肪酸(经甲酯化后)进行了测定,用色谱法作了定量,共鉴定出18种脂肪酸。 相似文献
993.
The alkylation of 1-aryl-substituted dihydro-2,4(1H,3H)-pyrimidinediones with methyl 2-bromoacetate has been studied followed
by hydrolysis and condensation of the products with o-phenylenediamine. The compounds have been identified by NMR, and IR
spectrometry and mass spectrometry. Structural characteristics in the 1H and 13C NMR spectra of the synthesized are discussed.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 1095–1105, July, 2007. 相似文献
994.
995.
N. I. Petrenko N. V. Elantseva V. Z. Petukhova M. M. Shakirov E. E. Shul'ts G. A. Tolstikov 《Chemistry of Natural Compounds》2002,38(4):331-339
New derivatives of betulonic acid containing on C-28 fragments of amino acids or their methyl esters were prepared as potential biologically active agents. 相似文献
996.
V. B. Sokolov T. V. Goreva T. A. Epishina A. Yu. Aksinenko 《Russian Chemical Bulletin》2007,56(11):2255-2257
Earlier unknown representatives of fluorine-containing α-chloroalkylisocyanates, viz., esters of 2-chloro-3,3,3-trifluoro-2-isocyanatopropionic acid, were obtained. Synthetic potentialities of these compounds
in the preparation of 2-substituted derivatives of 3,3,3-trifluoroalanine were demonstrated.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2179–2181, November, 2007. 相似文献
997.
S. A. Hovakimyan A. V. Babakhanyan V. S. Voskanyan V. E. Karapetian G. A. Panosyan S. T. Kocharian 《Chemistry of Heterocyclic Compounds》2004,40(8):1047-1051
The reaction of methyl esters of 3-methyl-2-oxo- and 2-oxo-3-phenyl-3-pentenoic acids with hydrazine hydrate and phenylhydrazine was used to synthesize new pyridazinone derivatives. These products are formed through intermediate hydrazides with subsequent cyclization. 4-Hydroxy-3-oxotetrahydropyridazines are mainly formed using equimolar amounts of the starting reagents, while the corresponding hydrazones of 3,4-dioxohexahydropyridazines are formed in the case of a two-fold excess of hydrazine hydrate or phenylhydrazine. Evidence was obtained indicating the existence of a keto–enol tautomerism for 4-hydroxy-3-oxopyridazines. 相似文献
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