Pre-atmospheric depths and thermal histories of Canyon Diablo spheroids
摘要:
Abstract— Despite having melted during formation, seven of eight Canyon Diablo spheroids weighing from 0.6 to 13 mg retain cosmic‐ray‐produced 38Ar (38Arcos) in concentrations (10−10 cm3 STP/g) ranging from 0.35 to 68. The presence of 38Arcos is consistent with pre‐atmospheric depths of <2.3 m and most likely rules out an origin for the spheroids deep within the projectile, which had a radius of ˜15 m. Low levels of 21Necos indicate gas loss from these spheroids. Relative to most Canyon Diablo meteorites, the spheroids contain lower concentrations of cosmogenic noble gases. The difference partly reflects diffusion losses from the spheroids, especially for 3He and 21Ne, but also suggests deeper locations on average for the precursor material, consistent with independent results from 59Ni.
在厌氧条件下,S-亚硝基硫醇1a-e通过SN键的均相裂解而发生热分解。该反应导致可逆地形成一氧化氮和亚硫烷基。速率常数k(t)已在不同温度下根据在回流烷烃溶剂中进行的动力学测量确定。叔亚硝基硫醇1c(k1(69摄氏度)= 13 x 10(-3)min(-1))和1d(k1(69摄氏度)= 91 x 10(-3)min(-1))分解更快比主要亚硝基硫醇1a(k1(69摄氏度)= 3.0 x 10(-3)min(-1))和1b(k1(69摄氏度)= 6.5 x 10(-3)min(-1))。活化能(E#= 20.5-22.8 Kcal mol(-1))已根据Arrhenius公式计算得出。在有氧条件下,S-亚硝基硫醇1a-e的降解是由N2O3催化的自催化链分解过程引起的。后者通过双氧与内源性和/或外源性一氧化氮反应形成。通过去除内源性一氧化氮或存在抗氧化剂(例如对甲酚,β-苯乙烯和BHT),强
在无水卤化铜 (II) 存在下,各种芳基胺与亚硫硝酸叔丁酯、亚硫硝酸叔丁酯或对甲苯磺酰亚硝酸酯在温和条件下反应,以良好的收率得到相应的芳基卤化物。在丙烯腈、苯乙烯和丙烯酸等烯烃存在下,该反应得到相应的 2-芳基-1-卤代乙烷作为主要产物。由于硫-氮键较弱,亚硝酸叔丁酯、亚硝酸叔丁酯和对甲苯磺酰亚硝酸酯是比亚硝酸烷基酯或硝酸烷基酯更好的脱氨基试剂。
Reactions of Thionitrites or Thionitrates with Carbanions
作者:Koichi Shinhama、Yong Hae Kim、Shigeru Oae
DOI:10.1246/bcsj.53.1771
日期:1980.6
Reaction of several thionitrites (RSNO) or thionitrates (RSNO2) with carbanions such as Grignard reagents, alkyllithium, or the carbanion of diethyl malonate gave C-alkylthio derivatives such as sulfides or diethyl (alkylthio)malonates.
Dinitrogen tetroxide supported on polyvinylpyrrolidone (PVP–N2O4): a new nitrosating and coupling agent for thiols and a selective oxidant for sulfides and disulfides
S-nitrosothiols (thionitrites) using this new nitrosatingagent in n-hexane or CHCl3 at 10°C. With this reagent, thiols were also converted into their corresponding disulfides. Selective oxidation of sulfides to sulfoxides and disulfides to thiosulfonates can also be achieved by this reagent at room temperature. By using an excess of the reagent, the selective one-pot synthesis of thiosulfonates from thiols
将气态N 2 O 4固定在聚乙烯吡咯烷酮上,得到稳定的聚合试剂。硫醇转化为小号在使用这个新的亚硝化剂-nitrosothiols(thionitrites)ñ -己烷或氯仿3在10℃下。使用该试剂,硫醇也被转化为其相应的二硫化物。在室温下,也可以通过该试剂将硫化物选择性氧化为亚砜,将二硫化物选择性氧化为硫代磺酸盐。通过使用过量的试剂,在室温下也从硫醇选择性地一锅合成硫代磺酸盐。
Dinitrogen Tetroxide–Impregnated Charcoal (N<sub>2</sub>O<sub>4</sub>/Charcoal): Selective Nitrosation of Amines, Amides, Ureas, and Thiols
Abstract Efficient N‐nitrosation of amines, amides, and ureas, and also S‐nitrosation of thiols were performed with dinitrogentetroxide impregnated on activated charcoal (N2O4/charcoal) in CH2Cl2 at room temperature. High selectivity was observed for N‐nitrosation of dialkyl amines, N‐alkylamides and N‐alkylureas. Dealkylation and N‐nitrosation of trialkylamines were also performed by this reagent
Copper(I) Nitrosyls from Reaction of Copper(II) Thiolates with <i>S</i>-Nitrosothiols: Mechanism of NO Release from RSNOs at Cu
作者:Shiyu Zhang、Nihan Çelebi-Ölçüm、Marie M. Melzer、K. N. Houk、Timothy H. Warren
DOI:10.1021/ja406476y
日期:2013.11.13
serve as ready sources of biological nitric oxide activity, especially in conjunction with copper centers. We report a novel pathway for the generation of NO within the coordination sphere of copper model complexes from reaction of copper(II) thiolates with S-nitrosothiols. Reaction of tris(pyrazolyl)borate copper(II) thiolates (iPr2)TpCu-SR (R = C6F5 or CPh3) with (t)BuSNO leads to formation of (iPr2)TpCu(NO)
Proline-based phosphoramidite reagents for the reductive ligation of S-nitrosothiols
作者:Chung-Min Park、Tyler D Biggs、Ming Xian
DOI:10.1038/ja.2015.144
日期:2016.4
we report the development of proline-based phosphoramidite substrates that can effectively convert RSNOs to proline-based sulfenamides through a reductiveligation process. A unique property of this method is that the phosphine oxide moiety on the ligation products can be readily removed under acidic conditions. In conjugation with the facile preparation of RSNOs from the corresponding thiols (RSHs)