A series of enantioenriched 4,5,6,7-tetrahydrofuro[2,3-b]pyridines were accessed by a cycloisomerization/cycloaddition strategy. Starting from ynamide derivatives and aldehydes, yields ranging 27 to 90% high levels stereoselectivity (de>95%, 93–99% ee) obtained through sequential relay catalysis. The concurrent use gold complex with diphenylprolinol silyl ether was applied combination diversely...

A facile, efficient, single-step protocol for the synthesis of difluoromethyl enol ether derivatives by O-difluoromethylation of 1,3-diones via in situ generation of difluorocarbene from ClCF2CO2Et has been developed. The functional group tolerance, scalability of the reaction, and mild reaction conditions make it an attractive protocol for the synthesis of biologically relevant difluoromethyl ...

To circumvent the limitations of polyethylene glycol (PEG) modified carriers, a photo-triggerable liposome was prepared which was modified by cholesterol derivatives via a cleavable vinyl ether linkage so that the PEGylated coating can be efficiently removed by a photoactivated fullerene. After the photocleavage of the PEG moiety, the intracellular uptake of the photo-triggerable liposome impro...

C–H activation of the methyl group of toluene and related ArCH3 derivatives by 2,3-dichloro-4,5-dicyano-1,4-benzoquinone (DDQ) gives insertion products, ArCH2O[C6Cl2(CN)2]OH via a rate-determining hydride abstraction by DDQ. The resulting benzylic ether can undergo reactions with phosphines to give benzylic phosphonium salts (Wittig reagents) and with phosphites to give phosphonate esters (Horn...

Several ether and ester derivatives of aryl aldoximes have been synthesized from the aryl aldehydes. Structures of all new products were established by spectral methods. Many of the obtained compounds showed higher activity against fungal pathogens Botrytis cinerea, Fusarium culmorum, Phytophthora cactorum, and Rhizoctonia solani than the reference substance chlorothalonil, reaching 100% inhibi...

A short, monodisperse additive (octa(ethylene glycol) monophenyl ether) functions to suppress aggregation of thermally and chemically denatured lysozyme. Control studies with shorter and non-amphiphilic derivatives revealed that the amphiphilic structure is essential, and octa(ethylene glycol) is nearly the minimum chain length for amphiphilic poly(ethylene glycol)s to stabilize proteins.

New crown ether Schiff base derivatives were prepared by the condensation of 4'-formylbenzo-15-crown-5 or 4'-formyl-5'-hydroxybenzo-15-crown-5 with 1,2-bis(2-aminophenoxy)ethane. The structures of these new compounds were confirmed on the basis of elemental analysis, IR, (1)H- and (13)C-NMR, UV-Vis and mass spectroscopic data.

A halogen-induced oxidative rearrangement of N,O-ketals prepared from cyclobutanones, leading to pyrrolidone derivatives, is developed. The reaction proceeds via an iminium ether intermediate and, depending on the reaction medium, two types of pyrrolidone derivative, containing a halogen atom or hydroxyl group, can be obtained.

An efficient route to the complex L-kedarosamine alpha-glycosidic ether 2, a synthetic precursor to kedarcidin chromophore, is described. Central to the route, which is suitable for the preparation of multigram amounts of material, is a short synthetic sequence from D-threonine to protected L-kedarosamine derivatives and methodology for their alpha-selective coupling with appropriate hydroxyl a...