The use of enaminones and enamines as effective synthons for MSA-catalyzed regioselective synthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles
In the present work, an efficient regioselectivesynthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles via a methanesulfonic acid (MSA)-catalyzed reaction of hydrazones with enaminones or enamines is reported. Mechanistically, the formation of the title compounds involves the [2+3] cycloaddition of hydrazones with enaminones or enamines followed by aromatization with acid and oxygen. This
Aryl Pyrazoles from Photocatalytic Cycloadditions of Arenediazonium
作者:Luana Cardinale、Michael Neumeier、Michal Majek、Axel Jacobi von Wangelin
DOI:10.1021/acs.orglett.0c02514
日期:2020.9.18
conditions (rt, 20 min) with catalytic [Ru(bpy)3]2+ under blue-light irradiation and exhibited compatibility with several functional groups (e.g., I, SF5, SO2NH2, N3, CN) and perfect levels of regiocontrol. Mechanistic studies (luminescence spectroscopy, CV, DFT, radical trapping, quantum yield determination) documented an initial oxidative quenching of the excited photocatalyst and the operation of
Several aldehyde and ketonephenylhydrazones were electrooxidized in MeOH. Electrooxidation in the presence of KI or tetraethylammonium p-toluenesulfonate as the supporting electrolyte afforded the corresponding methoxy(phenylazo)alkanes. whereas electrooxidation in the presence of KI, NaCN, and HOAc afforded the cyano(phenylazo)alkanes.
几种醛和酮苯腙在 MeOH 中被电氧化。在 KI 或对甲苯磺酸四乙基铵作为支持电解质的情况下进行电氧化,得到相应的甲氧基(苯偶氮)烷烃。而在 KI、NaCN 和 HOAc 存在下的电氧化得到氰基(苯偶氮)烷烃。
Reduction of hydrazines to amines with aqueous solution of titanium(iii) trichloride
作者:Yan Zhang、Qiang Tang、Meiming Luo
DOI:10.1039/c1ob05328k
日期:——
cleavage in hydrazines is widely used in the preparation of amines and thus occupies a significant place in organic synthesis. In this paper, we report a new method for the reductive cleavage of N–N bonds in hydrazines by commercially available and cheap aqueous titanium(III) trichloride. The reaction proceeds smoothly under a broad pH range from acidic to neutral and basic conditions to afford amines in good
Enamine chemistry. Part III. Reaction of αβ-unsaturated acid chlorides with enamines of acyclic ketones. Preparation of cyclohexane-1,3-diones
作者:J. R. Hargreaves、P. W. Hickmott、B. J. Hopkins
DOI:10.1039/j39680002599
日期:——
isopropyl ketone and the dimethylamine enamine of di-isopropyl ketone gave 2,2,4-trimethyl- and 2,2,4,4-tetramethyl-cyclohexane-1,3-diones respectively. The morpholine enamine of dibenzyl ketone gave 3-morpholino-2,4-diphenyl-cyclohex-2-enone which could not be hydrolysed to the cyclohexane-1,3-dione. The mechanism of the reaction is discussed.