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61.
E. A. Dikusar V. I. Potkin N. G. Kozlov S. K. Petkevich N. V. Kovganko 《Chemistry of Natural Compounds》2006,42(3):254-258
Previously undescribed 2-bromo-3,4,4-trichlorobut-3-enoates 1b-23b were synthesized in 84–91% yield from natural alcohols including terpenes and steroids, plant phenols, and oximes of natural
carbonyl compounds 1a-23a by reaction of 2-bromo-3,4,4-trichlorobut-3-enoyl chloride in the presence of pyridine.
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Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 212–215, May–June, 2006. 相似文献
62.
Apurba ChetiaAnil Saikia Chandan J. SaikiaRomesh C. Boruah 《Tetrahedron letters》2003,44(13):2741-2744
The reaction of 16-DPA with P4S10 in refluxing benzene afforded a novel adduct 16-DPA-P2S5 instead of the expected thione. The adduct undergoes [4+2]cycloaddition with alkyne dienophiles to afford steroidal (17,16-c)pyrans. 相似文献
63.
Novel steroidal phosphoramidate conjugates of 3'-azido-2',3'-dideoxythymidine(AZT)and amino acid esterswere synthesized and determined by positive and negative ion electrospray ionization mass spectrometry.The MSfragmentation behaviors of the steroidal phosphoramidate conjugates have been investigated in conjunction withtandem mass spectrometry of ESI-MS/MS.There were three characteristic fragment ions in the positive ion ESImass spectra,which were the Na adduct ions with loss of steroidal moiety,amino acid ester moiety from pseudomolecular ion(M Na)~ ,and the phosphoamino acid methyl ester Na adduct ion by α-cleavage of the phosphora-midate respectively.The main fragment ions in negative ion ESI mass spectra were the ion(M-HN_3)~-,the ion(M-AZT-H)~-,and the ion(M-steroidal moiety-H)~- besides the pseudo molecular ion(M-H)~-.Thefragmentation patterns did not depend on the attached amino acid ester moiety. 相似文献
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66.
N. V. Ivanchina T. V. Malyarenko A. A. Kicha A. I. Kalinovskii P. S. Dmitrenok 《Russian Chemical Bulletin》2008,57(1):204-208
Nine steroidal compounds including three new steroidal glycosides, viz., sodium (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol 15-sulfate (fuscaside A), (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol (fuscaside B), and (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentol (desulfated minutoside A); three previously known glycosides, viz., distolasterosides D1 and D2 and pycno-podioside A; two previously known polyhydroxysteroids, viz., 5α-cholestane-3β,6α,8,15β,16β,26-hexaol and 5α-cholestan-3β,4β,6α,7⇇8,15β,16β,26-octol; and the known sodium 24,25-dihydro-marthasterone
3-sulfate were isolated from the Far-Eastern starfish Lethasterias fusca. The structures of these compounds were elucidated by NMR spectroscopy and mass spectrometry.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–200, January, 2008. 相似文献
67.
Valentina Manzo Karla Ulisse Inés Rodríguez Eduardo Pereira Pablo Richter 《Analytica chimica acta》2015
The microextraction of diclofenac and mefenamic acid from water samples was performed by using rotating disk sorptive extraction (RDSE) with molecularly imprinted polymer (MIP) as the sorptive phase. The MIP was synthesized from the monomer 1-vinylimidazol (VI) together with the cross-linker divinylbenzene (DVB) using diphenylamine as the template molecule. Scanning electron microscopy (SEM) analyses of the MIP revealed clusters of spherical particles having a narrow size distribution, with diameters of approximately 1 μm. 相似文献
68.
An accurate, sensitive and least time consuming reverse phase high performance liquid chromatographic (RP‐HPLC) method for the estimation of ceftriaxone in the presence of non steroidal anti‐inflammatory drugs in formulation and human serum has been developed and validated. Chromatographic separation was conducted on prepacked Purospher Star, C18 (5 μm, 250 × 4.6 mm) column at room temperature using methanol:water:acetonitrile (80:15:5 v/v/v) as a mobile phase, pH adjusted at 2.8 with ortho‐phosphoric acid and at a flow rate of 1.0 mL/minute, while UV detection was performed at 270 nm. The results obtained showed a good agreement with the declared content. The method shows good linearity in the range of 2.5‐25 μg/mL ceftriaxone serum concentrations with a correlation coefficient 0.999 (inter‐ and intra‐day RSD < 2.0%). The limit of detection and quantification for ceftriaxone and NSAID's in pharmaceutical formulation and serum were in the range 0.51‐1.54 μg/mL. Analytical recovery was >98.1%. The proposed method may be used for the quantitative analysis of commonly administered non steroidal anti‐inflammatory drugs i.e. tiaprofenic acid, naproxen sodium, flurbiprofen, diclofenac acid and mefenamic acid alone or in combination with ceftriaxone from raw materials, dosage formulations and in serum. The established HPLC method is rapid, accurate and selective, because of its sensitivity and reproducibility. 相似文献
69.