ABSTRACT
We fabricated polymeric micelles containing 5-fluorouracil (5-FU) or fluorescein using the amphiphilic block copolymer, poly-4-vinylpyridine-b-6-O-methacryloyl galactopyranose. Although the polymeric micelles were stable at pH 7.4, they readily decomposed at pH 5, resulting in near complete release of 5-FU. Uptake of polymeric micelles containing fluorescein by HepG2 and HCT116 cells was also investigated. With both cell types, strong fluorescence was observed after a 12-h incubation, but the fluorescence weakened after 24 h of incubation. The fluorescein incorporated into the polymeric micelles was released into acidic organelles (endosome and/or lysosome), from which it diffused throughout the cell. The cytotoxicity of polymeric micelles containing 5-FU was evaluated against HepG2 cells using a CCK-8 assay. The results suggest that polymeric micelles containing 5-FU are more cytotoxic to HepG2 cells than free 5-FU.
Subject(s)
Fluorouracil/chemistry , Micelles , Polymers/chemistry , Cell Survival/drug effects , Drug Carriers/chemistry , Dynamic Light Scattering , Fluorouracil/toxicity , HCT116 Cells , Hep G2 Cells , Humans , Hydrogen-Ion Concentration , Microscopy, ConfocalABSTRACT
We have established the first catalytic C-C and C-N bond formation reactions of O-heterocycles (e.g., tetrahydrofuran, phthalane, and lactone derivatives) using iron trichloride as a catalyst in the presence of TMSN3 or allylsilanes accompanied by the ring opening of O-heterocycles. The reactions smoothly proceeded at room temperature to give the corresponding primary saturated alcohols from the 2-substituted tetrahydrofurans, ortho-substituted benzyl alcohols from phthalanes, and saturated carboxylic acids from lactones in high yields.
Subject(s)
Alcohols/chemical synthesis , Allyl Compounds/chemistry , Azides/chemistry , Carboxylic Acids/chemical synthesis , Chlorides/chemistry , Ferric Compounds/chemistry , Heterocyclic Compounds/chemistry , Alcohols/chemistry , Carboxylic Acids/chemistry , Catalysis , Molecular StructureABSTRACT
We fabricated novel pH-sensitive polymeric micelles consisting of amphiphilic block copolymer containing pyridyl groups as side chains in the hydrophobic block. The number average particle diameter of the polymeric micelles at pH 7 was approximately 200 nm. A decrease in pH resulted in deformation of the polymeric micelles over a very narrow pH range (between pH 5.7 and 5.6). Interestingly, micellization and demicellization occurred reversibly in this narrow pH range. Polymeric micelles incorporating 5-fluorouracil (5FU) were also prepared. Decreasing the pH of this polymeric micelle solution from 7 to 5.5 resulted in the rapid release of 5FU at pH 5.6; the drug was completely released within 30 min. These results suggest that deformation of the polymeric micelles caused the rapid release of 5FU.
Subject(s)
Micelles , Polymers/chemistry , Pyridines/chemistry , Drug Carriers/chemistry , Fluorouracil/chemistry , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Polymerization , Polymers/chemical synthesisABSTRACT
The ring-opening allylation and azidation of 2,5-dihydrofurans has been accomplished with allyltrimethylsilane or Me(3)SiN(3) in the presence of catalytic amounts of HAuCl(4) x 3 H(2)O. Whereas the allylation proceeds regioselectively in the 2-position to afford 2,6-dien-1-ols, the azidation takes place in the 4-position exclusively.
ABSTRACT
The first total synthesis of (R,R,R)-bejarol and its (3R,5S,9R)-isomer has been accomplished which confirms the absolute configuration of the natural products. The key step is the gold-catalyzed cycloisomerization of the enantiomerically pure beta-hydroxyallenes 12/13 to the corresponding dihydropyrans 14/15.
