Synthesis of N-alkyl pyrroles via decarboxylation/dehydration in neutral ionic liquid under catalyst-free conditions

Abstract

A general route to N-alkyl pyrroles by reacting aromatic, heteroaromatic or aliphatic aldehydes with 4hydroxyproline in ionic liquid under neutral condition was developed. The ionic liquid can be readily recovered and reused up to 5 reaction cycles without any effect on the yield of the product formed. The utility of the protocol for one-pot synthesis of 9H-benzo[e]pyrrolo[2,1-b][1,3]oxazines is also presented.

Regioselective Metal-Free Decarboxylative Multicomponent Coupling of α-Amino Acids, Aldehydes and Isonitriles Leading to N-Substituted Azacyclic-2-carboxamides with Antithrombotic Activity

“…Thus, development of a new synthetic protocols for prolinamide synthesis employing readily available starting materials is an attractive synthetic target. Considering the widespread use of isonitriles for multicomponent reactions (MCR) and in our interest in decarboxylative reactions and isonitrile insertions, − we envisioned that decarboxylative MCR between l -proline, aldehyde, and isonitrile would offer a new metal-free approach to N -substituted prolinamides. It is worth mentioning that Ugi et al have reported a four-component MCR between an α-amino acid, aldehyde, isonitrile and alcohol to produce 1,1′-iminodicarboxylic acid derivatives .…”

Metal- and Solvent-Free Multicomponent Decarboxylative A3-Coupling for the Synthesis of Propargylamines: Experimental, Computational, and Biological Investigations

“…Thus, we got interested in carrying out the detailed optimization study and finding the mechanistic rationale of this metal-free decarboxylation reaction. Our initial focus was on the screening of various ionic liquids as they have shown potential in decarboxylation reactions . Thus, using [bmim]­Br, decarboxylative coupling of 1a (0.75 mmol), 2a (0.85 mmol), and 3a (1.00 mmol) afforded propargylamine 4a in 38% yield (Table ; entry 2) while using [bmim]­OAc, 4a could be obtained in 15% yield (Table ; entry 1).…”