Strategies for synthesis of 1,2,4-triazole-containing scaffolds using 3-amino-1,2,4-triazole

Molecular Diversity - 1,2,4-Triazole-containing scaffolds are unique heterocyclic compounds present in an array of pharmaceuticals and biologically important compounds used in the drug-discovery...     

Some reactions of diphosphenes and related species

Abstract

Some reactions of diphosphenes and the related species involving oxidation, reduction, alkylation, sulfurization, and ⁶η-coordination are described.     

Direct Introduction of a Dimesitylboryl Group Using Base‐Mediated Substitution of Aryl Halides with Silyldimesitylborane

The first dimesitylboryl substitution of aryl halides with a silylborane bearing a dimesitylboryl group in the presence of alkali‐metal alkoxides is described. The reactions of aryl bromides or iodides with Ph₂MeSi?BMes₂ and Na(OtBu) afforded the desired aryl dimesitylboranes in good to high yields and with high borylation/silylation ratios. Selective reaction of the sterically less‐hindered C?Br bond of dibromoarenes provided monoborylated products. This reaction was used to rapidly construct a D‐π‐A aryl dimesityl borane with a non‐symmetrical biphenyl spacer.     

钒取代的杂多酸催化一锅四组分Dakin-West反应合成β-乙酰氨基酮(英文)

The multicomponent condensation of an aryl aldehyde,acetyl chloride,acetonitrile,and enolizable ketone as one-pot synthesis of β-acetamido ketones in high yields was investigated using commercial,non-corrosive,and environmentally benign Keggin and Wells-Dawson heteropolyacid catalysts.The best catalyst was H5PW10V2O40.The methodology used simple experimental conditions,and the short reaction times and high yields indicate it is a useful strategy for the large scale synthesis of β-acetamido ketones.     

Structural, optical and electromagnetic properties of aluminum-clay nanocomposites

Aluminum pillared and exchanged bentonite particles were synthesized by the ion exchange method. The characteristics of the particles were investigated by Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), electron dispersive X-ray spectrometer (EDS), reflectance spectrophotometer (RS) and electromagnetic transition instrument (ETI). FTIR spectra showed a successful incorporation of Al complexes into the clay interlayer. The TGA result demonstrated an improvement in thermal stability of the Al-pillared clay compared with the untreated particles. SEM and EDX results showed the presence of aluminum aggregates on the surface of clay. It was also found that Al ions affect electromagnetic properties of the clay particles.     

A novel condition for capillary electrophoretic analysis of reductively aminated saccharides without removal of excess reagents

We have identified novel CE conditions for the separation of 7‐amino‐4‐methylcoumarin‐labeled monosaccharides and oligosaccharides from glycoproteins. Using a neutrally coated capillary and alkaline borate buffer containing hydroxypropylcellulose and ACN, saccharide derivatives form anionic borate complexes, which move from the cathode to the anode in an electric field and are detected near the anodic end. Excess labeling reagents and other fluorescent products remain at the cathodic end. Fluorimetric detection using an LED as a light source enables determination of monosaccharide derivatives with good linearity between at least 0.4 and 400 μM, may correspond to 140 amol to 140 fmol. The lower LOD (S/N = 5) is only 80 nM in the sample solution (ca. 28 amol). The results were comparable to reported values using fluorometric detection LC. The method was also applied to the analysis of oligosaccharides that were enzymatically released from glycoproteins. Fine resolution enables profiling of glycans in glycoproteins. The applicability of the method was examined by applying it to other derivatives labeled with nonacidic tags such as ethyl p‐aminobenzoate‐ and 2‐aminoacridone‐labeled saccharides.     

An Isotope‐Coded Fluorogenic Cross‐Linker for High‐Performance Target Identification Based on Photoaffinity Labeling

A photoaffinity labeling (PAL)‐based method for the rapid identification of target proteins is presented in which a high‐performance chemical tag, an isotope‐coded fluorescent tag (IsoFT), can be attached to the interacting site by irradiation. Labeled peptides can be easily distinguished among numerous proteolytic digests by sequential detection with highly sensitive fluorescence spectroscopy and mass spectrometry. Subsequent MS/MS analysis provides amino acid sequence information with a higher depth of coverage. The combination of PAL and heterogeneous target‐selecting techniques significantly reduces the amount of time and protein required for identification. An additional photocleavable moiety successfully accelerated proteomic analysis using cell lysate. This method is a widely applicable approach for the rapid and accurate identification of interacting proteins.     

Dehydration‐fragmentation mechanism of cathinones and their metabolites in ESI‐CID

Various cathinone‐derived designer drugs (CATs) have recently appeared on the drug market. This study examined the mechanism for the generation of dehydrated ions for CATs during electrospray ionization collision‐induced dissociation (ESI‐CID). The generation mechanism of dehydrated ions is dependent on the amine classification in the cathinone skeleton, which is used in the identification of CATs. The two hydrogen atoms eliminated during the dehydration of cathinone (primary amine) and methcathinone (secondary amine) were determined, and the reaction mechanism was elucidated through the deuterium labeling experiments. The hydrogen atom bonded to the amine nitrogen was eliminated with the proton added during ESI, in both of the tested compounds. This provided evidence that CATs with tertiary amine structures (such as dimethylcathinone and α‐pyrrolidinophenones [α‐PPs]) do not undergo dehydration. However, it was shown that the two major tertiary amine metabolites (1‐OH and 2″‐oxo) of CATs generate dehydrated ions in ESI‐CID. The dehydration mechanisms of the metabolites of α‐pyrrolidinobutiophenone (α‐PBP) belongs to α‐PPs were also investigated. Stable‐isotope labeling showed the dehydration of the 1‐OH metabolite following a simple mechanism where the hydroxy group was eliminated together with the proton added during ESI. In contrast, the dehydration mechanism of the 2″‐oxo metabolite involved hydrogen atoms in three or more locations along with the carbonyl group oxygen, indicating that dehydration occurred via multiple mechanisms likely including the rearrangement reaction of hydrogen atoms. These findings presented herein indicate that the dehydrated ions in ESI‐CID can be used for the structural identification of CATs.