One-pot preparation of isocyanides from amines and their multicomponent reactions: crucial role of dehydrating agent and base
作者:Sankar K. Guchhait、Garima Priyadarshani、Vikas Chaudhary、Darshan R. Seladiya、Tapan M. Shah、Nikita P. Bhogayta
DOI:10.1039/c3ra40347e
日期:——
A novel one-pot practical approach for the preparation of isocyanide directly from amine and its reaction has been developed. It employs formylation of amine, dehydration of formamide to isocyanide, and its multicomponent reactions (Ugi, Passerini, and Groebke–Blackburn–Bienaymé reactions). This method provides a significant solution to known synthetic difficulties of isocyanides. In this approach
A greener synthesis of α-acyloxyamides was achieved by one-pot three component cascade Passerini reactions in a deep eutectic solvent (DES). Reactions proceeded rapidly and afforded the corresponding α-acyloxyamides by a variety of aldehydes, acids and isocyanides in excellent yields. The DES has the advantages of easy workup, high yield, and an environmentally benign and, moreover, shortened time as the greatest exclusivity of this system compared with previously reported methods. Passerini three-component cascade reaction in a deep eutectic solvent: an environmentally benign and rapid system for the synthesis of α-acyloxyamides.
Microwave-assisted Passerini reactions under solvent-free conditions
作者:Angélica de Fátima S Barreto、Otilie E Vercillo、Carlos Kleber Z Andrade
DOI:10.1590/s0103-50532011000300008
日期:——
Various α-acyloxy carboxyamides were easily obtained combining three building blocks in one step: a carboxylic acid, an aldehyde and an isonitrile (Passerini reaction), using microwave irradiation under solvent-free conditions. The products were obtained in good yields (61-90%) and in short reaction times (< 5 min), using two different temperatures (60 and 120 ºC). At 120 ºC, the yields were higher and the reactions faster (< 1 min). Most of the obtained products are multifunctional allowing their application in consecutive Passerini reactions
A Passerini three component condensation between a carboxylic acid, an aldehyde, and an isocyanide at high temperature under solvent-free conditions was developed. This methodology allows the formation of a broad range of alpha-acyloxyamides in excellent yields in short reaction times. (C) 2011 Elsevier Ltd. All rights reserved.
Supported <i>p</i>-Toluenesulfonic Acid as a Highly Robust and Eco-Friendly Isocyanide Scavenger
作者:Jhonny Azuaje、Alberto Coelho、Abdelaziz El Maatougui、José Manuel Blanco、Eddy Sotelo
DOI:10.1021/co100035z
日期:2011.1.10
We document here the use of polymer-supported p-toluenesulfonic acid as a highly effective, robust, economical and eco-friendly isocyanide scavenger. The herein described strategy; circumvent the intense and repulsive odor of volatile isocyanides, enabling simplified and odorless workup and purifications. The usefulness of the new scavengers has been validated in a set of diverse isocyanide-based organic transformations and this approach is also amenable to parallel synthesis techniques.