Cobalt and Manganese Salts of p -Aminobenzoic Acid Supported on Silica Gel: A Versatile Catalyst for Oxidation by Molecular Oxygen
作者:Mohammed M. Hashemi、Yusef Ahmadibeni
DOI:10.1007/s00706-002-0534-3
日期:2003.2.1
A 1:1 molar ratio of the cobalt and manganese salts of p -amino benzoic acid supported on silica gel is an effective catalyst for the oxidation of various organic compounds in reasonable yields using molecular oxygen. The catalyst can be reused several times.
An oxidation system to synthesize pyridine derivatives has been developed by oxidation of 1,4-dihydropyridines and polyhydroquinoline derivatives in good yields.
已开发出一种氧化系统,通过氧化1,4-二氢吡啶和多羟基喹啉衍生物,可以高产率合成吡啶衍生物。
A simple, efficient, one-pot three-component domino synthesis of Hantzsch pyridines under solvent-free condition
In this article, efficient and simple preparation of Hantzschpyridine derivatives by reaction of various aldehydes and β-dicarbonyls in the presence of ammonium chlorate under solvent-free condition at 80°C is reported. The advantages of this system are the one-step procedure, high yields of the products, and the ability to carry out large-scale reactions. J. Heterocyclic Chem., (2009).
Facile Aromatisation of Hantzsch 1,4-Dihydropyridines by Autoxidation in the Presence of <i>P</i>-toluenesulfonic Acid in Acetic Acid
作者:Ding Zhang、Min Sha
DOI:10.3184/174751918x15208600846791
日期:2018.3
A simple protocol to achieve the aromatisation of Hantzsch dihydropyridines in high yield was established using p-toluenesulfonic acid in acetic acid and yields of 90% were obtained at room temperature. With regards to the Hantzsch1,4-dihydropyridines derived from alkyl aldehydes bearing one or more á-hydrogens, dealkylation products were obtained through a proposed autoxidation mechanism.
4-Substituted Hantzsch 1,4-dihydropyridines and 1,3,5-trisubstitutedpyrazolines were oxidized to the corresponding pyridines and pyrazoles, respectively, in high yields by molecular oxygen in the presence of catalytic amount of N-hydroxyphthalimide (NHPI) and Co(OAc)2 in acetonitrile at room temperature.