Practical preparation of N-(1-Alkynyl)sulfonamides and their remote diastereoselective addition to aldehydes via titanation

Aliphatic and aromatic sulfonamides were alkynylated with 1-bromo-1-alkynes in the catalytic presence of CuI to give N-(1-alkynyl)sulfonamides in good to excellent yields. The acetylene-titanium complexes generated from N-(1-alkynyl)benzosultams underwent diastereoselective addition to aldehydes. [reaction: see text]     

Application of 1-alkylamines to a liquid chromatographic/turbo ionspray tandem mass spectrometric method for quantifying metabolites of a new bone anabolic agent,TAK-778, in human serum

We investigated the application of alkylamines, as additives to the mobile phase, to a quantification method for the metabolites, M-III and M-IV, of TAK-778, which is a new bone anabolic agent, in human serum using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Prior to setting up the analytical method, we found that 1-alkylamines co-existing with M-III and M-IV in the turbo ionsprayed solution formed 1-alkylammonium adduct molecules of these metabolites during the ionization process, and the abundance of the adduct ions was considerably higher than that of protonated molecules ([M + H](+)s) of these metabolites. Based on these findings, we investigated a variety of 1-alkylamines and their spiked concentrations in the mobile phase for LC/MS/MS analysis to obtain higher sensitivities for the quantification of these metabolites. After these examinations, we found that 1-hexylamine at a final concentration of 0.05 mmol l(-1) was the most suitable additive for the mobile phase, and set the selected reaction monitoring (SRM) ions for the 1-hexylammonium adduct molecule and [M + H](+), allowing about a fivefold gain in the SRM chromatographic peak compared with that without 1-hexylamine. The adduct ion was considered to be formed by interaction between the amino group of 1-hexylamine and the phosphoryl group of M-III and M-IV. The internal standard (I.S.) used was deuterated M-III for each metabolite. The analytes and I.S. were extracted with diethyl ether from serum samples at neutral pH and injected into the LC/MS/MS system with a turbo ionspray interface. The limit of quantification for both analytes was 0.5 ng ml(-1) when 0.1 ml of serum was used, and the calibration curves were linear in the range 0.5-100 ng ml(-1). The method was precise; the intra- and inter-day precisions of the method were not more than 5.6%. The accuracy of the method was good, with deviations between added and calculated concentrations of M-III and M-IV being typically within 16.6%. This method provided reliable pharmacokinetic data for M-III and M-IV after the intramuscular administration of TAK-778 sustained-release formulation in humans.     

The effect of bath pH on electrodeposition and corrosion properties of ternary Fe-W-Zn alloy platings

Journal of Solid State Electrochemistry - As a new trial to improve the corrosion resistance of the Fe-W alloy platings, Fe-W alloys incorporating a small amount of Zn, namely novel ternary Fe-W-Zn...     

Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography with fluorescence detection using a deuterated internal standard

A high-performance liquid chromatographic method has been developed for the quantification of 1-hydroxypyrene (1-OHP) in human urine using deuterated 1-hydroxypyrene ([2H9]1-OHP) as an internal standard with fluorescence detection. [2H9]1-OHP was prepared enzymatically from deuterated pyrene ([2H10]Pyr) with cytochrome P450 1A1. It eluted immediately prior to non-deuterated 1-OHP on alkylamide-type reversed-phase columns and had nearly the same fluorescence characteristics as non-deuterated 1-OHP. The detection limit was 0.1 microg/L and the calibration range was from 1 to 100 nmol/L. Urine sample treatment involved enzymatic hydrolysis followed by solid-phase extraction using Sep-Pak C18 cartridges. The proposed method was used to determine urinary 1-OHP in smokers and non-smokers.     

Janus‐Cube Octasilsesquioxane: Facile Synthesis and Structure Elucidation

A perfect “Janus‐cube” octasilsesquioxane, a nanometer‐scale Janus particle with two different types of substituents, was synthesized through the cross‐coupling of a “half‐cube” cyclic sodium siloxanolate with another half‐cube cyclic fluorosiloxane. The structure was confirmed by X‐ray crystallography to be a Janus cube. The overall synthesis is simple and does not require drastic separation methods compared with previous methods. The synthesis of the Janus cube demonstrates a novel siloxane bond‐forming reaction involving the coupling a silanol salt and fluorosilane. The reaction is mild, does not result in acid generation, and could be applied to the construction of other novel siloxane compounds.     

Hexakis(2,4,6-triisopropylphenylsilsesquioxane)

Hexasilsesquioxanes bearing bulky Tip (2,4,6-triisopropylphenyl) groups were synthesized and the structure was determined. The X-ray crystal analysis revealed that the enantiomer pair originating from the restricted rotation of the bulky Tip groups was included in the single lattice. In solution, evidence for the rapid interconversion of both enantiomers was encountered in ¹H NMR. Thus, variable temperature NMR indicated peak broadeningupon warming the sample, with a coalescence temperature of 38 ° C. Kinetic parameters of the rotation were also calculated.     

Planarity recognition of cationic dyes by anionic, crystalline bilayer aggregates

Steric selectivity in terms of molecular planarity of cationic dyes was investigated using anionic bilayer aggregates. Planar cationic dye (para-type stilbazolium) could be incorporated into the hydrophobic region of anionic crystalline bilayer aggregates, whereas structurally related, less planar dyes (ortho-type stilbazolium) could not be incorporated in spite of somewhat higher hydrophobicity resulting from lengthening of the N-alkyl group.