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《Carbohydrate research》1986,148(2):279-285
2,3,4,6,1′,3′,4′-Hepta-O-benzylsucrose, obtained by acid-catalysed hydrolysis of the 6′-O-trityl derivative, was oxidised with the Pfitzner-Moffatt reagent and the product was alkylated with methylmagnesium iodide. Removal of the protecting groups then gave a mixture of diastereomers, namely 7-deoxy-β-d-altro and -α-l-galacto-hept-2-ulofuranosyl α-d-glucopyranoside. Application of this reaction sequence to 2,3,4,1′,3′,4′,6′-hepta-O-benzylsucrose afforded β-d-fructo-furanosyl 7-deoxy-dl-glycero-α-d-gluco-heptopyranoside. 相似文献
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The reaction of 6′-chloro-6′-deoxyraffinose deca-acetate with a variety of nucleophilic anions (Br-,I-,N-3) gave the corresponding 6′-substituted raffinoses. The 6′-azide was further converted into 6′-amino-6′-deoxyraffinose, isolated as its N-acetyl derivative, and silver fluoride-induced elimination of hydrogen iodide from the 6′-iodide gave the 6′-deoxy-5′-ene. Treatment of 6′-chloro-6′-deoxyraffinose and 6′,6″-dichloro-6′,6″-dideoxyraffinose with base afforded, respectively, 3′,6′-anhydro-and 3′,6′;3″,6″-dianhydro-raffinose in high yields. In addition, the dichloride was converted into 6′,6″-diazido-6′,6″-dideoxyraffinose. 相似文献
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《Inorganica chimica acta》1988,147(1):77-85
Polarographic half-wave potentials for two reduction steps of 49 cyclopentadienyliron complexes of substituted arenes or heterocycles in dimethylformamide were determined. A fast cyclic voltammetry (10–40 V/s) was used to study the electron transfer kinetics of some of these complexes. After correction for the double layer effects, the rate constants of all the complexes studied show that the transfer of electrons in the second reduction step occurs significantly faster than in the first one. This was interpreted as a result of greater delocalization of electrons in the 20-electron complexes of iron compared to the 19-electron complexes. 相似文献
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Sang J. Na Anthony G. DiLella Edward V. Lis Keith Jones David M. Levine David J. Stone J. F. Hess 《Neurochemical research》2010,35(5):761-772
Convection enhanced delivery of 6-hydroxydopamine (6-OHDA) to the rat striatum results in a model of Parkinson’s disease.
An important feature of this unilateral model is the progressive loss of dopaminergic (DA) neurons over the course of several
weeks. To improve the understanding of this model, gene expression changes in the substantia nigra, which contains the DA
neuron cell bodies, and the striatum, which contains the DA neuron synaptic terminals, were examined using DNA microarrays.
Samples were collected and behavior was analyzed from vehicle and toxin treated animals at 3 days, 1 week, 2 weeks and 4 weeks
following 6-OHDA treatment. Tissue DA content was determined and samples from animals which exhibited a substantial depletion
of striatal DA were included in the subsequent gene expression analysis. The results of the gene expression analysis indicated
that 6-OHDA elicits a vigorous inflammatory response, comprised of several distinct pathways, in the striatum at the earliest
time point tested. In contrast, relatively few gene expression changes were observed in the SN at the 3-day time point. In
both tissues examined there was evidence for a vigorous inflammatory response at the 1- and 2-week time points, which was
substantially diminished by the 4-week time point. Inflammation plays a prominent role in the 6-OHDA model of Parkinson’s
disease. 相似文献
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C. Marcin R. White C. Hirsch F. Ferris R. Sykes D. Houck R. Greasham M. Chartrain 《Journal of industrial microbiology & biotechnology》1991,8(3):157-164
Summary An actinomycete (MA 6474, ATCC 53828) isolated from a soil sample (Mutare, Zimbabwe) was found to biotransform the sodium salt of Simvastatin (MK-733) to 6--hydroxymethyl MK-733, 6--hybroxymethyl MK-733, and 6-ring-hydroxy MK-733. The bioconversion efficiency to the desired compound, 6--hydroxymethyl MK-733, was enhanced by optimizing the physico-chemical parameters of the process. In shake flask cultures, addition of magnesium (0.125 mg/l Mg SO4·7H2O) to the medium resulted in a five-fold increase in the rate of bioconversion to the diastereomer. The ratio of bioconversion products (6--hydroxymethyl, 6--hydroxymethyl, and 6-ring-hydroxy MK-733) was regulated by pH. Process improvements and scale up in 23-1 fermentors, which consisted of a controlled addition of substrate (MK-733), resulted in a 2-fold increase in alpha diastereomer Production (42 vs. 79 U/ml) and a 23-fold rate increase in the formation of -diastereomer. A high diastereomeric ratio (: =91) facilitated downstream processing. 相似文献
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6-Tuliposide B is a secondary metabolite occurring specifically in tulip anthers. Recently, a potent antibacterial activity of 6-tuliposide B has been reported. However, its molecular target has not yet been established, nor its action mechanism. To shed light on such issues, 6-tuliposide B and tulipalin B analogues were synthesized and a structure–activity relationship (SAR) was examined using a broad panel of bacterial strains. As the results of SAR among a total of 25 compounds, only tulipalin B and the compounds having 3′,4′-dihydroxy-2′-methylenebutanoate (DHMB) moieties showed any significant antibacterial activity. Moreover, the 3′R analogues of these compounds displayed essentially the same activities as 6-tuliposide B and the structure of the 3′R-DMBA moiety was the same as that of the proposed active moiety of cnicin. These results suggest that 6-tuliposide B has the same action mechanism as proposed for cnicin and bacterial MurA is one of the major molecular targets of 6-tuliposide B. 相似文献
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Selective acid-catalysed methanolysis of 2,3,2′,3′-tetra-O-benzyl-4,6:4′,6′-di-O-benzylidene-α,α-trehalose yielded the monobenzylidene derivative, which was converted into the 4,6-dimesylate. Selective nucleophilic displacement of the primary sulphonyloxy group then gave 2,3-di-O-benzyl-6-deoxy-6-fluoro-4-O-mesyl-α-d-glucopyranosyl 2,3-di-O-benzyl-4,6-O-benzylidene-α-d-glucopyranoside. Removal of the protecting groups then yielded 6-deoxy-6-fluoro-α,α-trehalose. In addition, 6-deoxy-6-fluoro-4-O-mesyl-α,α-trehalose and a derivative of 4-chloro-4,6-dideoxy-6-fluoro-α-d-galactopyranosyl α-d-glucopyranoside were also prepared from the same substrate. Iodide displacement of 2,3-di-O-benzyl-4,6-di-O-mesyl-α-d-glucopyranosyl 2,3-di-O-benzyl-4,6-di-O-mesyl-α-d-glucopyranoside afforded the 6-iodide and 6,6′-di-iodide in yields of 31 and 36%, respectively. Similarly, the 6-azide and 6,6′-diazide were isolated in yields of 17 and 21%, respectively. 相似文献
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Patients with chronic inflammatory disorders such as rheumatoid arthritis (RA) have a high risk of developing cardiovascular disease. We evaluated the effects of TNF-α and IL-6 on foam cell formation, a pivotal process in atherogenesis. Accumulation of intracellular oxidized LDL (oxLDL) was induced when THP-1/macrophages were stimulated with TNF-α or IL-6. TNF-α induced the expressions of scavenger receptors SR-A and LOX-1, and IL-6 induced SR-A expression. Inhibition of the NF-κB signaling markedly decreased TNF-α-induced foam cell formation and SR-A expression. Serum from RA patients, but not healthy subjects, induced foam cell formation, which was partially reversed by either IL-6 or TNF-α blockade in conjunction with inhibiting the induction of scavenger receptors. The present study clearly showed that in patients with chronic inflammation mediated by TNF-α and IL-6, these cytokines are directly implicated in atherosclerotic plaque formation. 相似文献
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