Improvement in flow-sheet of extraction chromatography for trivalent minor actinides recovery

Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate...     

Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis

The direct 2‐deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2‐deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2‐deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2‐deoxyglycosylation of amide groups using a newly designed Brønsted acid catalyst under mild conditions. Through mechanistic investigations, we discovered that the amide group can inhibit acid catalysts, and the inhibition has made the 2‐deoxyglycosylation reaction difficult. Diffusion‐ordered two‐dimensional NMR spectroscopy analysis implied that the 2‐chloroazolium salt catalyst was less likely to form aggregates with amides in comparison to other acid catalysts. The chlorine atom and the extended π‐scaffold of the catalyst played a crucial role for this phenomenon. This relative insusceptibility to inhibition by amides is more responsible for the catalytic activity than the strength of the acidity.     

General Formation of Macro-/Mesoporous Nanoshells from Interfacial Assembly of Irregular Mesostructured Nanounits

Mesoporous core–shell nanostructures with controllable ultra-large open channels in their nanoshells are of great interest. However, soft template-directed cooperative assembly to mesoporous nanoshells with highly accessible pores larger than 30 nm, or even above 50 nm into macroporous range, remains a significant challenge. Herein we report a general approach for precisely tailored coating of hierarchically macro-/mesoporous polymer and carbon shells, possessing highly accessible radial channels with extremely wide pore size distribution from ca. 10 nm to ca. 200 nm, on diverse functional materials. This strategy creates opportunities to tailor the interfacial assembly of irregular mesostructured nanounits on core materials and generate various core–shell nanomaterials with controllable pore architectures. The obtained Fe,N-doped macro-/mesoporous carbon nanoshells show enhanced electrochemical performance for the oxygen reduction reaction in alkaline condition.     

Remarks on unit indices of imaginary abelian number fields II

Satz 41 in Hasse's monograph [4] is modified because of the incorrectness of Satz 29. We investigate unit indices of imaginary abelian number fields of type (2,2) and (2,2, 2), some of which give counterexamples to Satz 41. We moreover give a relation between unit indices of certain imaginary fields of type (2,2²) and those of their real cyclic subfields.     

Extending the possibility of an N-Troc-protected sialic acid donor toward variant sialo-glycoside synthesis

The potential of an N-Troc-protected sialic acid donor, equipped with phenylsulfenyl functionality as a leaving group, has been explored. As a result, the entitled donor was proven to be highly reactive and to have broad applicability toward the synthesis of variant sialo-glycans, which have N-glycolyl, de-N-acetyl, 1,5-lactam and 8-O-sulfo sialic acid analogs.     

Linear optical switching in a FLC/waveguide composite device

A fast electrooptic modulation in a polymer waveguide using a ferroelectric liquid crystal has been proposed. In this device, the surface stabilized ferroelectric liquid crystal and the soft mode ferroelectric liquid crystal are used as an active material on the passive polymer waveguide, and electrooptic switching is realized by controlling the total reflection at the polymer waveguide-liquid crystal interface. The response time is of the order of several microseconds. The analogue electrooptic modulation in the waveguide is realized using the field induced linear molecular tilt of the electroclinic effect in the soft mode ferroelectric liquid crystal.     

(Triisopropylsilyl)acetaldehyde acetal as a novel protective group for 1,2-diols

(Triisopropylsilyl)acetaldehyde dimethyl acetal (TIPS-ADMA) was synthesized from chlorotriisopropylsilane in three steps. Cyclic and acyclic 1,2-diols can be transformed to (triisopropylsilyl)ethylidene acetals (TIPS-AA). Removal of the acetal by LiBF₄ regenerates the starting diol in excellent yield even in the presence of an acetonide of 1,2-diol. The TIPS-AA group can survive under the deprotection conditions of the acetonide in acetic acid at 80 °C. Selective protection of 2,3- and 4,6-diols for O-methyl d-mannoside with TIPS-ADMA and selective deprotection of the acetals have been achieved.     

Studies on the formation of aliphatic aldehydes in the plasma and liver of vitamin E-deficient rats

The effects of vitamin E (E) deficiency on the formation of aliphatic aldehydes in rat plasma and liver were studied. Three-week-old Wistar male rats were fed either an E supplemented diet (2-ambo-alpha-tocopheryl acetate 20 mg/kg diet, designated as E supplemented diet group) or an E deficient diet (E deficient diet group). After 8 weeks, n-hexanal and (E)-4-hydroxy-2-nonenal (4-HN) in the plasma of the E deficient diet group were found to be 2.0 and 2.5-fold greater than those of the E supplemented diet group, respectively. The contents of aldehydes such as n-pentanal, n-hexanal, 4-HN in the liver were also significantly higher in the E deficient diet group than in the E supplemented diet group. These results indicate that some aldehydes, arising possibly from lipid peroxides, are produced and detected in the plasma and liver of rats under the condition like E deficiency. In this study we further found that the activity of the liver aldehyde dehydrogenase (ALDH, EC 1.2.1.3) was significantly changed; 5 and 8 weeks after the start it was lower in the E deficient diet group when compared to that in the E supplemented diet group. The decrease of enzyme activity was related to the increase of aldehydes such as n-hexanal in the liver. the aldehyde increase in the plasma of the E deficient diet group was thought to raise the injury of cells, namely, a strong hemolysis on erythrocytes prepared from the blood of rats fed the E deficient diet.     

Organic phosphorus compounds. IV. Asymmetric 4-(benzothiazol-2-yl)benzylphosphonates as potent calcium antagonistic vasodilators

Various asymmetric or cyclic ester derivatives of the phosphonic acid moiety in the calcium antagonist fostedil (KB-944) were synthesized. The coronary vasodilator activity of these compounds was assessed by Langendorff's method. Among them, the ethyl isopropyl ester 12 showed the most potent activity, which was comparable to that of fostedil.