N-芳氧基-β-二酮化二价阴离子(11a,b)的两个实例已经从市售化学品以多克级合成法以四步合成。合成方案依赖于将2,6-二异丙基苯胺和2-氨基-4-叔丁基苯酚(1a)(或2-氨基-4,6-二叔丁基苯酚(1b))依次添加到乙酰丙酮中, Et 3 OBF 4作为活化剂。两个活化试剂的性质和添加伯胺的加入顺序对反应的结果产生重大的影响,和酸催化剂(如硫酸或p-甲苯磺酸)通过形成苯并恶唑衍生物(3a,b)导致β-二酮骨架的分解。使用二价阴离子11A,b,单-和二(ñ -芳氧基-β-二亚胺基)锆(IV),镱(III),钍(Ⅳ),和铀(IV)已合成(配合物12 - 18),通过盐易位反应,并结合1 H / 13 C NMR光谱,元素分析和X射线晶体学进行表征。两种配体的空间体积不同,并且表现出不同的配位行为,这是根据几何考虑加以合理化的。
Kinetic investigations of the reactions of hinderedphenols with<i>N</i>-fluoro-1,4-diazoniabicyclo[2.2.2]octanesalt analogues
作者:Stojan Stavber、Marjan Jereb、Marko Zupan
DOI:10.1002/poc.444
日期:2002.1
bis(tetrafluoroborate) (Selectfluor™, F-TEDA-BF4) in acetonitrile in the absence or presence of various sources of external nucleophile (alcohols, water, trifluoroacetic acid) were studied. The reactions exhibited overall second-order kinetics, whereas products formation was strongly dependent on reaction conditions. Fluorination took place in neat MeCN; in the presence of water or alcohols, para quinols or
sensitive groups (hydroxyl, cyano, amino, vinyl, ethynyl, ester, and even acetyl groups) and heterocycles, which affords functionalized benzoxazoles in good to excellent yields by employing low catalyst loading (2 mol % Cu). The characterization and plausible catalytic mechanism of Cu(OH)x/OMS-2 are described. The notable features of our catalytic protocol such as the use of air as the benign oxidant
Divers benzoxazole heterocyclic products have been synthesized by a facile, efficient, and eco‐friendly strategy. The synthesis of benzoxazoles was catalyzed by nanostructured iron(III)‐porphyrin complex at room temperature under green conditions.
was applied for the synthesis of benzoxazoles via a C(aryl)−OH functionalization of catechol derivatives and amines in ethanol at room temperature. In the next step, aminoacids have been applied as nontoxic and cheap alternatives for amines. The obtained products were similar with the regular amines case. This is the first report about the application of aminoacids as alternatives for primary amines
One-Pot Multicomponent Reaction of Catechols, Ammonium Acetate, and Aldehydes for the Synthesis of Benzoxazole Derivatives Using the Fe(III)–Salen Complex
作者:Hashem Sharghi、Jasem Aboonajmi、Mahdi Aberi
DOI:10.1021/acs.joc.0c00560
日期:2020.5.15
The Fe(III)-salen complex has been applied successfully as a catalyst for the novel, simple, efficient, and one-pot multicomponent synthesis of benzoxazole derivatives from catechols, ammonium acetate as the nitrogen source, and aldehydes (nontoxic and cheap alternatives of amines) for the first time. Using this procedure, a wide range of benzoxazoles was successfully synthesized in the presence of