Synthesis of 4-methyl-2,3-disubstituted quinoline scaffolds via environmentally benign Fe(iii) catalysed sequential condensation, cyclization and aromatization of 1,3-diketone and 2-ethynylaniline

Abstract

Environmentally benign Fe(III)-catalysed sequential condensation, cyclization and aromatization of 1,3diketone and 2-ethynylaniline derivatives to the substituted quinoline scaffolds with good to excellent yield in shorter reaction time is described.

Synthesis of Nitrogen-Containing Heterocyclic Scaffolds through Sequential Reactions of Aminoalkynes with Carbonyls

“…The procedure also accomplished the preparation of quinoline dimers 43 with alkyl or aryl linkers at C-4 (Scheme 43). Alternatively, the one-pot synthesis of 4-methyl-2,3-disubstituted quinolines 44 was allowed by means of the inexpensive iron(III)catalyzed sequential condensation, cyclization and aromatization of 1,3-diketones with 2-ethynylaniline derivatives (Scheme 44) [61]. Furthermore, a cost-effective p-TsOH promoted synthetic strategy for the synthesis of substituted quinolines was explored by the reaction between levulinic acid with different 2-alkynylanilines under mild metal-free solventless conditions (Scheme 45) [62].…”

“…Scheme 43Scheme 43. Synthesis of dimeric quinolines 43.Alternatively, the one-pot synthesis of 4-methyl-2,3-disubstituted quinolines 44 was allowed by means of the inexpensive iron(III)catalyzed sequential condensation, cyclization and aromatization of 1,3-diketones with 2-ethynylaniline derivatives (Scheme 44)[61].…”

Annulation of 2‐Alkynylanilines: The Versatile Chemical Compounds

“…The use of 2,3‐dihydro‐1 H ‐inden‐1‐one ( 98 , n=0) gave no desire product [84] . Sivaraman and Perumal employed 1,3‐diketones to react with 2‐ethynylanilines, achieving 4‐methyl‐2,3‐disubstituted quinolines [85] …”

“…[84] Sivaraman and Perumal employed 1,3-diketones to react with 2-ethynylanilines, achieving 4-methyl-2,3-disubstituted quinolines. [85] Not only ketones, but also aldehydes can be treated with 2-alkynylanilines.…”