Efficient and Mild Protocol for the Synthesis of 4(3)-Substituted 3(4)-Nitro-1H-pyrroles and 3-Substituted 4-Methyl-2-tosyl-1H-pyrroles from Nitroolefins and Tosylmethyl Isocyanide in Ionic Liquids

✍ Scribed by Jie Qin; Ji Zhang; Bo Wu; Zhangguo Zheng; Meng Yang; Xiaoqi Yu

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 81 KB
• Volume: 27
• Category: Article
• ISSN: 0256-7660
• DOI: 10.1002/cjoc.200990300

✦ Synopsis

Abstract

A mild and convenient method for the synthesis of 4(3)‐substituted 3(4)‐nitro‐1__H__‐pyrroles and 3‐substituted 4‐methyl‐2‐tosyl‐1__H__‐pyrroles from nitroolefins and tosylmethyl isocyanide (TosMIC) in ionic liquid 1‐butyl‐3‐methylimidazolium bromide ([bmIm]Br) was developed. The reactions were performed at room temperature with KOH as base with good yields in a short time (about 2 h). Some tough conditions, such as absolutely anhydrous organic solvents, low temperature, hazardous and expensive strong base or organic base, were not needed. The yields of 4(3)‐substituted 3(4)‐nitro‐1__H__‐pyrroles were moderate, but excellent yields were achieved for the preparation of 3‐substituted 4‐methyl‐2‐tosyl‐1__H__‐pyrroles. This strategy was quite general and it worked in a broad range of nitroolefins with aromatic, aliphatic or heterocyclic substituents. The recovered ionic liquid could be reused as solvent for several times without significant decrease of reaction yields.