RESUMEN
A mixture of taxols was prepared from 10-deacetyl-7-xylosyltaxanes by three-step reactions: redox, acetylation, and deacetylation. The mixture was separated by column chromatography on silica gel to afford Taxol, Taxol B (Cephalomannine) and Taxol C. The mixture of Taxol B and Taxol C was converted to Docetaxel by Schwartz's reagent. The structures of Taxol and Docetaxel were characterized by HPLC, 1 H-NMR, 13 C-NMR and MS. This synthetic process has expanded the source of biomass for the chemical semi-synthesis of Taxol and Docetaxel, reduced the production costs, and increased the biomass resource of taxanes.
Asunto(s)
Docetaxel/química , Paclitaxel/química , Taxoides/química , Acetilación , Cromatografía Líquida de Alta Presión , Docetaxel/síntesis química , Espectroscopía de Resonancia Magnética , Oxidación-Reducción , Paclitaxel/síntesis químicaRESUMEN
An efficient one-pot stepwise method to synthesize 3-styryl-4-arylcoumarins from simple alkynoates is demonstrated. On the basis of the control experiments, a possible mechanism involving light-driven radical cyclization and Pd-catalysed cross-coupling processes for this synthesis method is proposed. The results of X-ray analysis and spectroscopy experiments prove that the substituent effect has a significant influence on the absorption and emission properties of the synthesized 3-styryl coumarins.
RESUMEN
The efficiency of photocatalysts depends largely on the accessibility of reaction species to the active centre, the electron transfer and geometric matching between the active surface of the catalyst and reaction species. In this work, we successfully synthesized and designed one two-dimensional Mn(II) MOF with [Mn2(H2L1)(H2O)2(DMF)2]n·(CH3CH2OH)n (HSTC 3) by using MnCl2·4H2O and 5,5'-(anthracene-9,10-diyl)diisophthalic acid (H4L1), in which the adjacent layers are stacked with weak interactions, and the huge gap leads to the interpenetration between layers to form a 2D + 2D â 3D interpenetration frame. Based on the particularity of the structure of HSTC 3, ultrasonic wall breaking methods were tried to successfully peel HSTC 3 into nanosheets (HSTC 3-NS), thus achieving a significant improvement in a series of optoelectronic properties due to exposure to more active centres for HSTC 3-NS. These results significantly enhance the photocatalytic selective oxidation of thioether. This study provides a new insight into the post-synthesis modification of MOF photocatalyst and their application in photocatalytic organic synthesis.