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101.
Borcsa B Csupor D Forgo P Widowitz U Bauer R Hohmann J 《Natural product communications》2011,6(4):527-536
The term lipo-alkaloid is used for C19 aconitane alkaloids containing one or two long-chain fatty acid residues. Lipo-alkaloids are transesterified derivatives of the most toxic and highly effective diester-type diterpene alkaloids, such as aconitine, hypaconitine, mesaconitine. Lipo-alkaloids are native minor compounds of aconite drugs, but their amount significantly increases after traditional processing, which is a general method in the Far Eastern traditional medicinal systems. Analytical works demonstrated that cautious processing (usually boiling) of crude aconite roots decreases the amount of normal diterpene alkaloids and increases the concentration of lipo-alkaloids resulting in the reduction of toxicity of the drugs. Many papers reported that lipo-alkaloids occur as a complex mixture in the drugs, and the isolation of the individual components is extremely difficult. These compounds have been identified using highly sensitive analytical methods (HPLC-MS, NMR), and semisynthetic approaches have been developed to ensure lipo-alkaloids in pure form for pharmacological studies. This review summarizes the structure, chemistry, semisynthesis, analytics and bioactivities of lipo-alkaloids. On the basis of 32 references this is the first comprehensive study on this topic, covering the data of 173 compounds. 相似文献
102.
L. A. Oparina M. Ya. Khil’ko N. A. Chernyshova S. I. Shaikhudinova L. N. Parshina Th. Preiss J. Henkelmann B. A. Trofimov 《Russian Journal of Organic Chemistry》2005,41(5):661-666
A new catalytic system CsF-NaOH was developed for the synthesis of mono- and divinyl ethers of alkanediols exceeding in efficiency KOH. The nucleophilic addition of diols to acetylene in the presence of this system occurs both at enhance pressure (without solvent, 140–160°C) and atmospheric pressure (in DMSO medium, 100°C) of acetylene. Conditions were established of a selective preparation in a high yield of divinyl ethers from diols.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 677–683.Original Russian Text Copyright © 2005 by Oparina, Khil’ko, Chernyshova, Shaikhudinova, Parshina, Preiss, Henkelmann, Trofimov. 相似文献
103.
I. L. Preiss 《Journal of Radioanalytical and Nuclear Chemistry》1993,171(1):193-202
H. M. Clark introduced radiochemistry as an undergraduate program at Rensselaer in 1947. The development of the course and the companion courses under Clark and Preiss that now form the radiochemical educational experience at RPI is outlined. Prospects for the future directions of the field and the educational requirements are discussed. 相似文献
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J. Leonowich S. Pandian I. L. Preiss 《Journal of Radioanalytical and Nuclear Chemistry》1977,40(1-2):175-187
Problems involved in developing radioisotope sources and the characteristics of potentially useful radioisotopes for X-ray
fluorescence analysis are presented. Some of the isotopes, which are not in use but look very promising, are indicated. 相似文献
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