Ligand Free Approach for the Copper(II)‐Mediated C‐NH₂ Arylation of 4‐Quinolone Derivatives Under Ambient Condition

Abstract

Copper (II)‐mediated C‐NH2 arylation of both unprotected and protected 4‐quinolones under ambient condition has been developed. This is a ligand free, room temperature, rapid reaction protocol and found compatible with various sensitive functional groups. Moreover using this protocol, we have synthesized a library of diverse functionalized 4‐quinolone derivatives.

Recent advances in the synthesis of pharmaceutically active 4-quinolone and its analogues: a review

“…54 A ligand free copper(II) mediated selective C-NH 2 arylation of both unprotected and protected 4-quinolones under ambient conditions was reported by Ghosh and Das in 2018 (Scheme 45). 55 The coupling of substituted amino 4-quinolone 141 obtained through the reduction of the corresponding nitro 4quinolone with phenylboronic acid 142 in the presence of Cu(OAc) 2 $H 2 O and K 2 CO 3 in EtOH at room temperature afforded the corresponding N-arylated derivatives 143 in good to excellent yields. Functional groups, such as -Br, -Cl and -NO 2 , were well compatible in this reaction, whereas thiopheneboronic acid did not participate in the reaction at all.…”

Recent Developments in the Synthetic Strategies of 4‐Quinolones and Its Derivatives

“…The mechanism of the reaction is dissipated below in figure 7. [47] Samadi et al developed a novel, atom economical, environmentally benign, and efficient synthetic protocol for the synthesis of functionalized 4-quinolones in the presence of iron phosphate as a catalyst. The developed protocol was based on Conrad-Limpach synthesis of quinolones from aniline and βketoester.…”

Synthesis and Functionalization of 4‐Quinolones – A Progressing Story

“…Recently, Das and co‐workers devised a newer protocol for the Cu II ‐mediated selective C–NH 2 arylation of 4‐quinolones in both protected and unprotected form under ambient conditions (Scheme ) . This ligand‐free and rapid process is quite effective at room temperature.…”