Oxidation of 1,1-disubstituted hydrazines with benzeneseleninic acid and selenium dioxide. Facile preparation of tetrazenes
作者:Thomas G. Back、Russell G. Kerr
DOI:10.1139/v82-390
日期:1982.11.1
1,1-disubstituted hydrazines were oxidized with benzeneseleninic acid in methanol, generally producing the corresponding tetrazenes in high yield. Studies of the by-products of the reaction, of the effects of protic vs. aprotic solvents, and trapping experiments suggest that N-aminonitrenes are unlikely intermediates in this oxidation. An alternative mechanism involving a Pummerer-like reaction of seleninamides
applied to aldoxime triisopropylsilyl ethers and hydrazones bearing an easily removable phthaloyl protective group. The CN reduction of aldehyde‐derived substrates (oximeethers and hydrazones) is enabled by using 1,4‐dioxane as the solvent known to participate as the Lewis‐basic component in FLP‐type heterolytic dihydrogen splitting. More basic ketone‐derived hydrazones act as Lewis bases themselves in
B(C 6 F 5)3催化的氢化作用适用于带有易于去除的邻苯二甲酰基保护基的乙二肟三异丙基甲硅烷基醚和。醛衍生的底物(肟醚和as)的CN还原可通过使用1,4-二恶烷作为已知参与FLP型杂二氢裂解的路易斯碱组分的溶剂来实现。在FLP型二氢活化中,更多的碱性酮衍生的azo酮充当Lewis碱本身,因此在不给体的甲苯中成功氢化。醛和酮衍生的底物之间的反应性差异也反映在所需的催化剂负载量和二氢压力上。
One-pot synthesis of 1-alkyl-1H-indazoles from 1,1-dialkylhydrazones via aryne annulation
作者:Nataliya A. Markina、Anton V. Dubrovskiy、Richard C. Larock
DOI:10.1039/c2ob07117g
日期:——
The reaction of readily accessible 1,1-dialkylhydrazones with commercially available o-(trimethylsilyl)aryl triflates provides a direct one-step route to pharmaceutically important 1-alkylindazoles. The products are obtained in high yields by one-pot NCS-chlorination/aryne annulation or Ac2O-acylation/deprotection/aromatization protocols.
Visible Light‐Induced [3+2] Cyclization Reactions of Hydrazones with Hypervalent Iodine Diazo Reagents for the Synthesis of 1‐Amino‐1,2,3‐Triazoles
作者:Jun‐Ying Dong、He Wang、Shukuan Mao、Xin Wang、Ming‐Dong Zhou、Lei Li
DOI:10.1002/adsc.202001436
日期:2021.4.13
In this study, visible‐light‐induced [3+2] cyclization reactions of hydrazones with hypervalent iodine diazo reagents as diazomethyl radical precursors are reported. Mild reaction conditions, a broad substrate scope, and excellent functional group compatibility were observed. Furthermore, the synthetic utility was demonstrated by gram‐scale synthesis and elaboration to several value‐added products
study has led to the development of a novel, highly efficient, 1,2-perfluoro-alkyl/-aryl migration process in reactions of hydrate of 1-perfluoro-alkyl/-aryl-1,2-diketones with alcohols, which are promoted by a Zn(II)/bisoxazoline and form α-perfluoro-alkyl/-aryl-substituted α-hydroxy esters. With (-)-8-phenylmenthol as the alcohol, the corresponding menthol esters are generated in high yields with