One-pot multicomponent synthesis of highly substituted piperidines using p-toluenesulfonic acid monohydrate as catalyst

Abstract

p-Toluenesulfonic acid monohydrate (p-TsOHÁ H 2 O) is a highly effective and efficient catalyst for the onepot multicomponent coupling of aldehydes, amines, and b-ketoesters in EtOH at ambient temperature to give highly functionalized piperidines in high yields. This one-pot reaction has some important advantages such as the easy workup procedure, simple and readily available precursors, nontoxic and inexpensive catalyst, and good to high yields.

Application and developing of iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs) as an efficient and reusable heterogeneous nanocatalyst in the synthesis of heterocyclic compounds

“…Specially, C‐2 and C‐6 substituted piperidine molecules came from extracts of Dendrobates speciosus (Panamanian poison frogs) have demonstrated various activities such as cytotoxic, antifungal, hemolytic and anti‐HIV properties . Recently, the synthesis of titled compounds were reported using a large number of catalysts, such as bromodimethylsulfonium bromide (BDMS), cerium ammonium nitrate (CAN), p ‐TsOH.H 2 O, tetrabutylammoniumtribromide (TBATB), tartaric acid, Bi (NO 3 ) 3 .5H 2 O, InCl 3 , p ‐sulfonic acid calix[n]arenes, ZrOCl 2 .8H 2 O, I 2 , and sodium dioctyl sulfosuccinate (SDOSS). Herein we report a one‐pot three (is situ five)‐component synthesis of highly functionalized piperidines 7 from the reaction of two equivalents of aromatic aldehyde, two equivalents of aromatic amine, and β ‐ketoester in the presence of Fe/MWCNTs as an efficient, ecofriendly and reusable heterogeneous nanocatalyst in ethanol at ambient temperature (Scheme ).…”

Transition metal-free one-pot synthesis of nitrogen-containing heterocycles

“…The process is simple and provides a wide range of substrate scope with electron-withdrawing and electrondonating groups present on aniline and aldehyde (Scheme 91, Path D). p-Toluenesulfonic acid monohydrate in ethanol was also found as a suitable catalyst for the intramolecular Mannich needed for the preparation of piperidines (Scheme 91, Path E) [199]. Several other catalysts like trityl chloride for the synthesis of substituted piperidines from anilines, aldehydes, and 1,3-dicarbonyl compounds have also been discussed [200].…”

Ag/Tio2 Nano Thin Films Catalyzed Efficient Synthesis of 6-Amino-4-Aryl-3-Methyl-1,4-Dihydropyrano[2,3-C] Pyrazole-5-Carbonitriles At Green Conditions

“…[41][42][43][44][45] In continuation of our research on multi-component reactions, 46-49 herein we would like to describe the synthesis of dihydropyrano[2,3-c]pyrazole derivatives, our attention was drawn to the of Ag/TiO 2 nano thin films as an effective and highly reusable catalyst and the synthesis of dihydropyrano [2,3-c] pyrazole was investigated in the presence of this catalyst.…”