Synthesis of Air‐stable, Odorless Thiophenol Surrogates via Ni‐Catalyzed C−S Cross‐Coupling
作者:Valentin Magné、Liam T. Ball
DOI:10.1002/chem.201901874
日期:——
efficient catalytic method for the preparation of S‐aryl isothiouronium salts, and demonstrate that these air‐stable, odorless solids serve as user‐friendly sources of thiophenols in synthesis. Diverse isothiouronium salts featuring synthetically useful functionality are readily accessible by nickel‐catalyzed C−S cross‐coupling of (hetero)aryliodides and thiourea. Convenient, chromatography‐free isolation
The intramolecular NH···Cl hydrogen bond in urea derivatives containing the o-chlorophenyl group
作者:Yoshiyuki Mido、Tomoko Okuno
DOI:10.1016/0022-2860(82)85230-7
日期:1982.6
disubstituted ureas containing a halophenyl group have been examined in order to directly confirm the presence of an intramolecular NH···Cl hydrogenbond in the o -chloro analog. In chlorophenyl derivatives the v (N-H) band for the N-H bond adjacent to an o -chlorophenyl group is always lower than that for a N-H bond adjacent to a phenyl, m - or p -chlorophenyl group. The corresponding band in N-o -halophenyl-
摘要 为了直接证实邻氯类似物中分子内NH…Cl氢键的存在,已经研究了各种含有卤代苯基的双取代脲的溶液v (NH)振动。在氯苯基衍生物中,与邻氯苯基相邻的 NH 键的 v (NH) 带总是低于与苯基、间氯苯基或对氯苯基相邻的 NH 键的 v (NH) 带。No -halophenyl-N' -phenylureas, o -XPhUPh [U = HNC(O)NH] 中的相应谱带随着卤素原子大小或重量的增加而显着降低波数。o -XPhUPh 衍生物被推断为两个分子内 NH…X 氢键形式,NH 与 CO 基团反式或顺式。
Accelerated and Enantioselective Synthesis of a Library of P-Stereogenic Urea Phosphines
作者:Vijay S. Koshti、Ravindra P. Gote、Samir H. Chikkali
DOI:10.1002/ejoc.201801309
日期:2018.12.19
Reported here is a highly efficient and accelerated catalytic asymmetric synthesis of P‐stereogenic urea phosphines leading to a small library of 18 P‐chiralphosphorus compounds. The de novo [Pd‐(S,S) Me‐FerroLANE}(m‐phenylurea)(I)] catalyst tolerated various functional groups and furnished corresponding urea substituted phosphines with an enantiomeric excess of up to 62 %.
Multifunctional Crown-5-calix[4]arene-based Phase-Transfer Catalysts for Aromatic <sup>18</sup>F-Fluorination
作者:Won Chang Lee、Seok Min Kang、Byung Chul Lee、Sang Eun Kim、Dong Wook Kim
DOI:10.1021/acs.orglett.0c03604
日期:2020.12.18
Methylated bis-triethylene glycolic crown-5-calix[4]arene (M-BTC5A) as a phase-transfercatalyst showed the best performance among other analogues and even conventional Kryptofix 222 in the nucleophilic aromatic 18F-fluorination of diaryliodonium tosylate precursors owing to (i) the efficient release of reactive “naked” [18F]fluoride, (ii) the high stabilization of the precursor in the reaction, and, presumably
Stalactite basin structure of dynamical systems with transient chaos in an invariant manifold
作者:Vasily Dronov、Edward Ott
DOI:10.1063/1.166495
日期:2000.6
invariant manifold and another attractor not in the invariantmanifold. It is found that the boundary separating these basins has an interesting structure: The basin of the attractor not in the invariantmanifold is characterized by thin cusp shaped regions ("stalactites") extending down to touch the nonattracting chaotic set in the invariantmanifold. We also develop theoretical scalings applicable to