Reaction of the lithio-derivative of methoxyallene with hydrazones. Part 1: Synthesis and transformation of α-allenyl hydrazines
作者:Valérie Breuil-Desvergnes、Jacques Goré
DOI:10.1016/s0040-4020(01)00030-8
日期:2001.3
methoxyallene reacts with aldehyde hydrazones leading to expected α-allenyl hydrazines when ether is the solvent of the reaction. The yields are good as well as the diastereoselectivity observed in the case of SAMP-hydrazones. These hydrazines are cleanly transformed to N-dialkylamino-3-methoxy-3-pyrrolines when they are reacted with n-BuLi in THF. These compounds are sometimes accompanied by the isomeric
Structural studies by nuclear magnetic resonance—XIX
作者:G.J. Karabatsos、R.A. Taller
DOI:10.1016/s0040-4020(01)92600-6
日期:1968.1
Configurations and conformations were assigned to several aldehyde and ketone N,N-dimethyldrazones from analyses of their 60-Mc NMR spectra. Aldehyde, but not ketone, N,N-dimethylhydrazones exist exclusively in the syn configuration. Interpretation of the vicinal spin-spin coupling constants, JH1Hα, led to the conclusion that II and III are the minimum energy conformations of these compounds. The ΔH0
A new, high-yielding methodology for reducing hydrazones to hydrazines is described, which allows the synthesis of different mono-, di- and trisubstituted hydrazines. Moreover, the reduction step can be followed by an in situ reaction with a carboxylic acid making possible a ‘one-pot’ synthesis of trisubstituted hydrazides. The method is relatively general and, in principle, suitable for industrial
A Broadened Scope for the Use of Hydrazones as Neutral Nucleophiles in the Presence of H-Bonding Organocatalysts
作者:Daniel Pettersen、Raquel P. Herrera、Luca Bernardi、Franscesco Fini、Valentina Sgarzani、Rosario Fernandez、José M. Lassaletta、Alfredo Ricci
DOI:10.1055/s-2005-922791
日期:——
Using thioureas as H-bonding organocatalysts, nitroalkenes can be activated for the conjugateaddition of hydrazones as neutral nucleophiles. Formaldehyde derivatives react at the azomethine carbon as expected, whereas hydrazones from enolizable aldehydes behave as ene-hydrazines and react at the α-carbon instead. Ionic liquids were found to decrease the reaction times considerably compared to
使用硫脲作为 H 键合有机催化剂,硝基烯烃可以被激活,用于腙作为中性亲核试剂的共轭加成。正如预期的那样,甲醛衍生物在偶氮甲碱碳上反应,而来自可烯醇化醛的腙则表现为烯肼并在 α-碳上反应。发现与常用溶剂相比,离子液体可显着减少反应时间,而路易斯酸的替代活化导致反应物分解。