Bismuth compounds in organic synthesis. Deprotection of ketoximes using bismuth bromide-bismuth triflate

Ketoximes undergo deprotection in CH₃CN/acetone/H₂O (3:6:1) in the presence of 20-40 mol% BiBr₃/5 mol% Bi(OTf)₃. Bismuth(III) salts are relatively non-toxic, insensitive to air and inexpensive. These features coupled with the use of a relatively non-toxic solvent system make this method an attractive alternative to existing routes for deprotection of ketoximes.     

Monotone iterative technique for periodic boundary value problems with causal operators

In this paper, we develop the monotone iterative technique for periodic boundary value problems with causal operators.     

Differential equations with causal operators in a Banach space

In this paper, differential equations with causal operators in the framework of an arbitrary Banach space are studied. Basic results such as existence, uniqueness and global existence are proved. The theory of cones is employed to investigate the extremal solutions of such equations.     

Applications of bismuth(III) compounds in organic synthesis

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).     

Quantification of Antioxidant Properties in Popular Leaf and Bottled Tea by High-performance Liquid Chromatography (HPLC), Spectrophotometry,and Voltammetry

Polyphenols in plants such as tea may offer many health benefits. The leaf and bottled teas available on the market today are advertised with a strong emphasis on their antioxidant properties. In this study, we have quantified the total polyphenol, flavonoid, and theaflavin concentrations by simple colorimetric methods, measured the reactivity of polyphenols using direct and indirect oxidation methods, and identified specific polyphenols present using high-performance liquid chromatography in a variety of commercially available teas. We find that, per given volume, freshly brewed teas are richer in polyphenols and reactivity by a factor five or more compared to bottled teas. Within the brewed and bottled categories, white and green teas are richer in antioxidants than oolong and black teas although the differences are less than a factor of two. We also find that the presence of additives causes changes in antioxidant properties such as an enhancement in Cranberry Orange tea and a reduction in Earl Grey tea. Since we verified our results using several overlapping techniques, we are able to evaluate the analytical tools commonly used in antioxidant studies. We find that the Folin–Ciocalteu method of quantifying polyphenols is a good indicator of the relative antioxidant reactivity of teas.