Rh(III)-Catalyzed (4 + 1) Annulation of Pyrazol-3-ones with Alkynoates via <i>Ortho</i>-Alkenylation/Cyclization Cascade: Synthesis of Indazole-Fused Pyrazoles
作者:Wei-Jung Chiu、Hong-Ren Chen、Indrajeet J. Barve、Chung-Ming Sun
DOI:10.1021/acs.joc.2c01208
日期:2022.9.16
A facile synthesis of novel indazole-fused pyrazoles from pyrazol-3-ones and alkynoate esters/amides via Rh(III)-catalyzed sequential C–H activation/ortho-alkenylation/intramolecular cyclization cascade is reported. The important characteristic of this method is that the resulting scaffold bearing quaternary carbon has been obtained through unusual [4 + 1] rather than expected [4 + 2] addition where
A novel Ru(II)-catalyzed C-H activation and annulation reaction of N-arylpyrazol-5-ones and diaryl/arylalkyl-substituted alkynes is developed. Unlike the reported metal-catalyzed C-H activation and annulation reactions, in the present bidentate amine-ligand controlled C-H activation and annulation reaction, the annulation occurs via a 1,2-aryl shift to afford quaternary carbon-centered pyrimidoindolones.
Relative quantitation of glycans using stable isotopic labels 1-(d0/d5) phenyl-3-methyl-5-pyrazolone by mass spectrometry
A deuterium reagent, 1-(d5) phenyl-3-methyl-5-pyrazolone (d5-PMP), has been synthesized and used for relative quantitative analysis of oligosaccharides by mass spectrometry (MS) using d0/d5-PMP stable isotopic labeling. Previously reported permethylation-based isotopic labels generate variable mass differences, and reductive amination-based isotopic labels cause a loss of some acid-labile groups in carbohydrates. In contrast, d0/d5-PMP stable isotopic labeling is performed at the reducing end of glycans under basic conditions without desialylation, and the mass difference (Delta m = 10 Da) between the heavy form (d5-PMP derivative) and light form (d0-PMP derivative) of each glycan is invariable. When the two derivative forms of a glycan are mixed in equimolar amounts, a pair of peaks with a 10-Da mass differences is observed in the MS profile. The difference at relative intensity between the d0- and d5-PMP derivatives reflects the difference in quantity of glycans in two samples, making it possible to carry out both qualitative and relative quantitative analyses of glycans in glycomic studies. Application of this method on DP(2) to DP(6) maltodextrin oligosaccharides and N-linked glycans released from ribonuclease B and bovine fetuin demonstrates a 10-fold relative quantitative dynamic range, a satisfying reproducibility (coefficient of variation [CV] <= 8.34%), and good accuracy (relative error [RE] <= 5.1%) of the method. The suggested technique has been successfully applied for comparative quantitative analysis of free oligosaccharides in human and bovine milk. (C) 2011 Elsevier Inc. All rights reserved.
PYRAZOLINONE SCAVENGERS OF FREE RADICAL
申请人:Gant Thomas G.
公开号:US20100150899A1
公开(公告)日:2010-06-17
The present invention relates to new pyrazolinone scavengers of free radicals, pharmaceutical compositions thereof, and methods of use thereof.