Synthesis and evaluation of 24-(isopropyl[75Se]seleno)chol-5-en-3.beta.-ol
摘要:
Selenium-75-labeled 24-(isopropylseleno)chol-5-en-3 beta-ol (4) has been prepared by reaction of sodium isopropyl-[75Se]selenol [( 75Se]2) with 3 beta-acetoxy-24-bromochol-5-ene (3). This new 75Se-labeled adrenal imaging agent shows pronounced adrenal uptake in rats. The concentration of radioactivity in rat adrenals increased steadily from 1 to 24 h after injection and then decreased slowly over the 21-day period. After 3 days the adrenal/blood and adrenal/liver ratios were 85:1 and 32:1, respectively, which are sufficient for adrenal imaging by single photon techniques. After 6 h the adrenal/blood ratio was 17:1 and the adrenal/liver ratio was 7:1. We propose that these ratios are sufficiently high for positron emission tomography of the adrenals. The absorbed radiation dose values to human organs have been estimated for the 75Se- and 73Se-labeled agent.
Organometallic Reaction in Aqueous Media. Synthesis of α-Selenoesters By Reactions of α-Bromoesters With Diselenides Promoted By Metallic Tin
作者:Weixing Qian、Weiliang Bao、Yongmin Zhang
DOI:10.1055/s-1997-805
日期:1997.4
In aqueous conditions α-bromoesters can react with diselenides by metallic tin to give α-selenoesters in moderate to good yields.
在水相条件下,α-溴酯可以通过金属锡与双硒化合物反应,以中等至良好的产率得到α-硒酯。
Alkanethioimidoyl Radicals: Evaluation of β-Scission Rates and of Cyclization onto <i>S</i>-Alkenyl Substituents
作者:Matteo Minozzi、Daniele Nanni、John C. Walton
DOI:10.1021/jo0353637
日期:2004.3.1
Thioimidoyl radicals were generated by addition of alkylsulfanyl radicals to alkyl isonitriles and were characterized by electron paramagnetic resonance (EPR) spectroscopy. The β-scissions of their C•S−C bonds were studied by variable-temperature EPRspectroscopy and the fragmentation rate constants and activation energies were calculated. The scission rates depend on the stability of the released alkyl radicals
Sodium Selenosulfate from Sodium Sulfite and Selenium Powder: An Odorless Selenylating Reagent for Alkyl Halides to Produce Dialkyl Diselenide Catalysts
using aqueous EtOH as the solvent and avoiding the generation of a malodourous selenol intermediate, the selenylation reaction with Na2SeSO3 is much more environmentally friendly than conventional methods. Owing to the cheap and abundant starting materials and selenium reagents, our novel synthetic method reduces the production costs of dialkyl diselenides as organoselenium catalysts, thereby advancing
Na2SeSO3 可以通过 Na2SO3 与 Se 能量的反应原位生成,被发现是一种无味试剂,用于烷基卤化物的硒基化生成二烷基二硒化物。这些产品最近已被证明是羰基化合物的 Baeyer-Villiger 氧化、烯烃的选择性氧化或肟的氧化脱肟的良好催化剂。通过使用乙醇水溶液作为溶剂并避免产生恶臭的硒醇中间体,与传统方法相比,与 Na2SeSO3 的硒基化反应更加环保。由于起始原料和硒试剂廉价且丰富,我们的新合成方法降低了作为有机硒催化剂的二烷基二硒化物的生产成本,
Sterically encumbered hexakis(alkylseleno)benzenes: conformational behavior of hexakis(iso-propylselenomethyl)benzene toward Hg2+ ions on selective recognition
作者:Jai Deo Singh、Monika Maheshwari、Shabana Khan、Raymond J. Butcher
DOI:10.1016/j.tetlet.2007.11.007
日期:2008.1
An efficient synthesis and structural aspects of a novel class of hexakis(alkylseleno)benzenes [(RSeCH2)6C6] (R = Me, iPr, nBu, sBu, tBu, nPn, nHx, nOct, 1-methylnaphthalene) by the reaction of hexakis(bromomethyl)benzene with RSe− ions is demonstrated. Preliminary data on ion-sensing properties reveal that these species may act as selective ionophores for Hg2+ ions.
一类新型的六(烷基硒基)苯[[RSeCH 2)6 C 6 ](R = Me,i Pr,n Bu,s Bu,t Bu,n Pn,n Hx,n Oct ,1-甲基萘)由六的反应(溴甲基)苯与的RSe -离子是证明。有关离子感测特性的初步数据表明,这些物质可能充当Hg 2+离子的选择性离子载体。
Fluoroselenenylation of Acetylenes with Xenon Difluoride-Diorganyl Diselenides and Xenon Difluoride-Phenylseleno(trialkyl)silanes
A new, efficient method of fluoroselenenylation of terminal, and open-chain symmetric and unsymmetric disubstituted acetylenes and cycloalkynes, gives vicinal (E)-fluoroalkenyl selenides in moderate to high yields by addition of selenenyl fluoride equivalents. These are formed in situ from xenon difluoride and diaryl, dibenzyl or primary and secondary dialkyl diselenides. Alternatively, the benzeneselenenyl fluoride equivalent is formed by treatment of more reactive phenylselenotrialkylsilanes with xenon difluoride. The regiochemistry of the addition is strongly dependent on the steric effects of substituents bonded to the acetylene.