Multiple Isotopic Labels for Quantitative Mass Spectrometry
作者:Cain Morano、Xin Zhang、Lloyd D. Fricker
DOI:10.1021/ac801654h
日期:2008.12.1
Quantitative mass spectrometry is often performed using isotopically labeled samples. Although the 4-trimethylammoniumbutyryl (TMAB) labels have many advantages over other isotopic tags, only two forms have previously been synthesized (i.e., a heavy form containing nine deuteriums and a light form without deuterium). In the present report, two additional forms containing three and six deuteriums have been synthesized and tested. These additional isotopic tags perform identically to the previously reported tags; peptides labeled with the new TMAB reagents coelute from reversed-phase HPLC columns with peptides labeled with the lighter and heavier TMAB reagents. Altogether, these four tags allow for multivariate analysis in a single liquid chromatography/mass spectrometry analysis, with each isotopically tagged peptide differing in mass by 3 Da per tag incorporated. The synthetic scheme is described in simple terms so that a biochemist without specific training in organic chemistry can perform the synthesis. The interpretation of tandem mass spectrometry data for the TMAB-labeled peptides is also described in more detail. The additional TMAB isotopic reagents described here, together with the additional description of the synthesis and analysis, should allow these labels to be more widely used for proteomics and peptidomics analyses.
Hydrofluoromethylation of alkenes with fluoroiodomethane and beyond
作者:Sandrine M. Hell、Claudio F. Meyer、Sebastiano Ortalli、Jeroen B. I. Sap、Xuanxiao Chen、Véronique Gouverneur
DOI:10.1039/d1sc03421a
日期:——
for the direct hydrofluoromethylation of alkenes is reported for the first time. This straighforward silyl radical-mediated reaction utilises CH2FI as a non-ozone depleting reagent, traditionally used in electrophilic, nucleophilic and carbene-type chemistry, but not as a CH2F radical source. By circumventing the challenges associated with the high reduction potential of CH2FI being closer to CH3I than
首次报道了烯烃直接氢氟甲基化的方法。这种直接的甲硅烷基自由基介导的反应利用 CH 2 FI 作为非臭氧消耗试剂,传统上用于亲电、亲核和卡宾型化学,但不作为 CH 2 F 自由基源。通过规避与 CH 2 FI的高还原电位比 CF 3 I更接近 CH 3 I相关的挑战,并利用 C-I 键的有利键解离能,我们证明了原料缺电子烯烃被转化在 (Me 3 Si) 3的干预下,由净氢氟甲基化产生的产物蓝色 LED 激活下的 SiH。这种看似简单但功能强大的方法已扩展到一系列(卤)甲基自由基前体,包括 ICH 2 I、ICH 2 Br、ICH 2 Cl 和 CHBr 2 F,以及 CH 3 I 本身;因此后一种试剂能够直接加氢甲基化。这种多功能化学被应用于18 F-、13 C- 和 D- 标记的试剂以及复杂的生物相关烯烃,为药物化学和正电子发射断层扫描中的应用提供了五十多种产品。
First Evidence for the Formation of a Geminal Dizinc Carbenoid: A Highly Stereoselective Synthesis of 1,2,3-Substituted Cyclopropanes
作者:André B. Charette、Alexandre Gagnon、Jean-François Fournier
DOI:10.1021/ja017230d
日期:2002.1.1
Significant amounts of novel gem-dizinc carbenoids (RZnCHIZnR) are formed when diethylzinc is mixed with iodoform in CH2Cl2 at 0 degrees C. This reagent was shown to be effective in the cyclopropanation of butenediol derivatives to generate a cyclopropylzinc intermediate that could be trapped with a variety of electrophiles. 1,2,3-Substitutedcyclopropane derivatives are formed with excellent diastereoselectivities
The rs structures of propyl fluoride and differences in structures between rotational isomers
作者:Michiro Hayashi、Masaharu Fujitake
DOI:10.1016/0022-2860(86)80278-2
日期:1986.8
Microwave spectra of trans and gauche propylfluoride and its isotopically substituted species have been measured. The rsstructures of the trans and gauche isomers of this molecule are determined from the observed moments of inertia. It is found that the CCC angle values are largely different between two isomers, while the CCF angle values stay unchanged. The rsstructures of ethyl fluorosilane and ethylmethlyl
Infrared spectra of dueterated methyl germanes and the geometries of some GeH compounds
作者:D.C. McKean、M.W. Mackenzie、A.R. Morrisson
DOI:10.1016/0022-2860(84)87045-3
日期:1984.5
Abstract Infraredspectra have been recorded for CHD 2 GeH 3 and CH 3 GeHD 2 at a resolution of 0.06 cm −1 . The K structure of four perpendicular-type bands of the former, and one of the latter species, were analysed to give A 0 − B 0 = 1.2252 (8) and 1.2511 (18) cm −1 respectively. These data are used in conjunction with earlier microwave results to obtain a new ground state geometry for methyl germane: