ABSTRACT By cycloaddition reaction of sodium azide with chalcone in the presence of CuO as a catalyst in DMF a 1,2,3-triazole are prepared in reaction with pentafluoropyridine to give 2-(tetrafluoropyridin-4-yl)-1,2,3-triazole derivatives in good yields and high regioselectivity. The regioselectivity of the compounds are confirmed by 19F-NMR and other spectroscopy. GRAPHICAL ABSTRACT

One-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

the regioselective ring opening of styrene oxide using elemental iodine and bromine in the presence of disulfides as new catalysts was studied. the conductivity titration and uv spectroscopy were used to study the interaction of iodine with these catalysts. the results indicate that disulfide 11 is efficient in polyiodide formation, and can catalyze this reaction in excellent yield and high reg...

For the first time B-podands have been studied as an efficient and powerful catalysts in the ring opening of epoxides with azide anion in water. The reaction afforded the corresponding 1,2-azidoalcohols with high regioselectivity under mild reaction conditions and in a highly atom economic fashion.

isatin, n-methyl isatin and n-benzylisatin were smoothly monobrominated in the 5-position by treatment with pyridinium bromochromate (pbc) in acetic acid medium. in the similar conditions indigo underwent bromination and oxidation to give 5-bromoisatin in high yield.

Thermotoga neapolitana beta-glucosidase (BglA) was subjected to site-directed mutagenesis in an effort to increase its ability to synthesize arbutin derivatives by transglycosylation. The transglycosylation reaction of the wild-type enzyme displays major beta(1,6) and minor beta(1,3) or beta(1,4) regioselectivity. The three mutants, N291T, F412S, and N291T/F412S, increased the ratio of transgly...

one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. in this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

Typical transition metal-catalyzed oxycyclization of allenols takes place at the terminal allene carbon via a 5-endo path and forms dihydrofurans. A copper-catalyzed protocol brought about reversed regioselectivity, generating series trisubstituted epoxides through 3-exo-cyclization/sulfonylation cascade. The current stoichiometry control regioselectivity may open singular opportunities in chem...

The regioselective ring opening of styrene oxide using elemental iodine and bromine in the presence of disulfides as new catalysts was studied. The conductivity titration and UV spectroscopy were used to study the interaction of iodine with these catalysts. The results indicate that disulfide 11 is efficient in polyiodide formation, and can catalyze this reaction in excellent yield and high reg...

EB (electron beam) irradiation of sulfonamide within a beta-cyclodextrin (beta-CD) inclusion complex in the solid state induced the solvent-free Fries rearrangement, which proceeded at a shorter reaction time with reversed regioselectivity by inclusion into the beta-CD, compared with that of sulfonamide crystals; the beta-CD as a restricted nanospace had a large effect on the reactivity and reg...