Current Progress in the Multicomponent Catalytic Synthesis of Amidoalkyl- Naphthols: An Update

Abstract

Amidoalkyl-2-naphthol is one of the vital synthetic intermediates which occupy an imperative position in medicinal chemistry due to its amazing biological, pharmacological as well as industrial and synthetic applications. Owing to its diverse pharmaceutical activities, hundreds of scientific literature are available, signifying the efficient synthesis of this intermediate using various catalysts. Most of these literature methods suffer from low yield and harsh reaction conditions that further ignited the researcher to explore for another green catalyst and fresh methodologies. This review summarizes the last five years progress in the catalytic synthesis of 1-amidoalkyl-2-naphthols using various heterogenous, homogenous and nanocatalysts along with their mechanism of action. Various advantages like green synthesis, atom economy, clean reaction profile and catalyst recovery are discussed which facilitate the scientist to probe and stimulate the study on this scaffold. In the end, the catalysts and reactions condition are organized into the tables for swift at a glance understanding of different catalysts used with their yield and time taken for the synthesis.

Recent Advances in the Reactions of β-Naphthol at α-Position

“…2019 年, 周永波课题 组 [29] 也报道了 β-萘酚与烯烃的选择性烷基化, 该反应使 用 Brønsted 酸亚磷酸活化萘酚, 同时使烯烃形成碳鎓离 子中间体, 实现亲电加成, 该体系具有较好的区域选择 性, 官能团耐受性好. Friedel-Crafts alkylation of β-naphthols with enamines 此外, 2016 年 Nakata 课题组 [30] 的应用广泛, 酰胺通过水解可以很容易地转化为具有重 要生物学意义的氨基烷基萘酚 [6,[31][32] , 通过多组分反应 (MCR)制备酰胺烷基萘酚是一种对环境友好且简单有 效的合成方法, 具有合成步骤少、反应时间短及副产物 少等优点 [6] .…”

Enantioselective [3 + 2] annulation of tryptanthrin-derived ketimines and 2-naphthols: access to polycyclic indolo[2,1-b]quinazoline derivatives

“…7 The asymmetric reactions of 2-naphthol catalyzed by CPAs have also received considerable attention. 8 Based on these research backgrounds, we envisioned that the CPA-catalyzed asymmetric reaction of tryptanthrin-derived ketimines with 2-naphthol would undergo an aza-Friedel–Crafts reaction between the imine group and the 1-position of 2-naphthol, followed by an intramolecular cyclization from the hydroxyl group of the 2-naphthol to the CN double bond of the amidine moiety (Scheme 1d). If successful, such a reaction would result in the formation of optically active heptacyclic dihydronaphthofuran-fused indolo[2,1- b ]quinazoline derivatives.…”

“…Employing 2-methoxynaphthalene 6 as a substrate to react with 1a under the standard conditions, no reaction was observed (Scheme 5), which indicates that the O–H group of naphthol is crucial for the success of this asymmetric [3 + 2] annulation. Given the experimental results and literature reports, 5,6 a ,8 plausible transition states (Scheme 6) have been proposed to illustrate the reaction pathway and stereochemistry of the reaction. The annulation was considered to comprise two steps: an aza-Friedel–Crafts reaction and an intramolecular cyclization.…”