Photooxygenation of pyrazin-2(1h)-ones

1-Alkyl-5,6-diphenylpyra2in-2(1H)-ones (1a-b) reacted with singlet oxygen in dichloromethane to afford the stable endoperoxide (1a-b), while in methanol to afford the 1:1-adduct (3a-b) of the endoperoxide (2a-b) and methanol.     

Synthesis of Δ1[9]- and/or Δ8[9]-dehydroindolizidines and related compounds

A facile synthesis of Δ^1[9]- and/or Δ^8[9]-dehydroindolizidine and related compounds, consisting of dry distillation of γ-(N-2-piperidinonyl)butyric acid over soda-lime, is described. Reductions of these dehydroindolizidines and stereochemistry of 1-methylindolizidine are also described.     

Recent insights into iron homeostasis and their application in graminaceous crops

Higher plants utilize various mechanisms to maintain iron homeostasis. To acquire sparingly soluble iron from the rhizosphere, graminaceous plants synthesize natural iron (III) chelators known as mugineic acid family phytosiderophores (MAs). Recent research has uncovered various genes involved in iron uptake and translocation, as well as factors regulating the expression of these genes, especially in rice. Manipulation of these molecular components is used to produce transgenic crops with enhanced tolerance to iron deficiency, or with a high seed iron content. Since iron homeostasis is closely linked to that of other mineral elements, an understanding of this phenomenon will serve as the basis for the production of crops with low concentrations of toxic metals and transgenic plants for phytoremediation.     

Trivial source modules in blocks with cyclic defect groups

We shall present a method to get trivial source modules easily just by looking at values of ordinary characters at non-identity p-elements in finite groups instead of doing huge calculation. The method is only for a case where defect groups are cyclic. Nevertheless, it works well at least when we want to prove Broué’s abelian defect group conjecture for blocks which have elementary abelian defect groups of order p ².     

Three new acyclic diterpene glycosides from the aerial parts of paprika and pimiento

Paprika and pimiento are used as vegetables and spices. We have obtained three new acyclic diterpene glycosides, called capsianosides XVII (1), V methyl ester (2) and XIV (3) together with capsianosides I and II from the aerial parts of paprika and pimiento. The structures of these compounds have been established by (1)H- and (13)C-NMR spectra and two-dimensional NMR methods.     

Coordination of divalent metal cation to amide group to form adduct ion in FAB mass spectrometry: implication of Zn2+ in enzymatic hydrolysis of amide bond

The structures of complexes between amides and metal ions were examined by FAB mass spectrometry and collision-induced dissociation (CID). Zn2+ was coordinated by the amide carbonyl oxygen atom of N-tetradecylacetamide (1). In contrast, Ca2+ and Mg2+ were coordinated by the amide group of 1 in both the keto and enol forms. The catalytic role of Zn2+ at the active site of the hydrolases might partly be explained by the effective attack of Zn2+ on carbonyl oxygen atom of the scissile amide group.     

Simultaneous determination of phosphonate, phosphate, and diphosphate by capillary electrophoresis using in-capillary complexation with Mo(VI)

This study describes the simultaneous determination of phosphonate, phosphate, and diphosphate by CE with direct UV detection, based on in-capillary complexation with Mo(VI). When a mixture of phosphonate, phosphate, and diphosphate was injected into a capillary containing 3.0 mM Mo(VI), 0.05 M malonate buffer (pH 3.0) and 45% v/v CH3CN, three well-defined peaks, due to the migration of the corresponding polyoxomolybdate anions, were separated. The respective calibration graphs were linear in the concentration range of 2 x 10(-6)-2 x 10(-4) M for phosphonate, 1 x 10(-6)-5 x 10(-5) M for phosphate, and 1 x 10(-6)-2 x 10(-4) M for diphosphate; the correlation coefficients were better than 0.9990. The present CE method is successfully applied to the simultaneous determination of phosphonate, phosphate, and diphosphate in tap water.     

Hypervalent iodine(III)/Et4NBr combination in water for green and racemization-free aqueous oxidation of alcohols

We have found that the use of the PhI(OAc)₂/Et₄N⁺Br⁻ combination in water can significantly enhance its oxidation ability and oxidize a wide range of alcohols 1 to carbonyl compounds 2 in good to excellent yields. This clean aqueous oxidation method shows no detectable racemization processes, and even an enolizable ketone 2m could be obtained in an optically pure form from the corresponding chiral alcohol 1m. Utilization of the recyclable reagent 3 as a more practical alternative to PhI(OAc)₂ is also successful in these reactions.