Ionic Liquid [EMIM]OAc under Ultrasonic Irradiation towards Synthesis of 1,4‐DHP's

Abstract

The ionic liquid 1-ethyl-3-methylimidazole acetate ([EMIM]OAc) was found to be a mild and effective catalyst for the efficient, one-pot, three-component synthesis of 1,4-dihydropyridines from arylaldehydes, ethylacetoacetate/acetylacetone and ammonium acetate at room temperature under sonication. The developed method has many advantages, including devoid of harmful catalysts, reacting at room temperature, higher yields in a simple methodology or operational convenience.

Synthesis of Novel Hantzsch Dihydropyridine Derivatives

“…In view of different biological and chemical applications of 1,4-dihydropyridine derivatives, the development of suitable synthetic approach for their generation has been a topic of great interest in recent times. Although many publications have already reported the synthesis of 1,4-dihydropyridine derivatives [22][23][24][25][26][27][28] , very little has been covered regarding the 2,6-dimethyl-N,Nbis-(4-aryl)-4-aryl-1,4-dihydropyridine-3,5-dicarboxamide derivatives 35 . Kumar et al 35 were the first who described the method of employing the reaction of p-chloro acetoacetanilide, aromatic aldehyde and excess of aqueous ammonia solution using ethanol as a solvent under reflux condition.…”

“…1, 4-Dihydropyridines are generally synthesized by classical Hantzsch reaction, which involves the condensation of an aldehyde, β-ketoester and ammonia or ammonium acetate in refluxing ethanol or acetic acid for a longer time 22 . There are several efficient methods developed for the synthesis of 1, 4-dihydropyridines which comprise the use of metal triflates 23 , TMSCL-NaI 24 , ionic liquid 25,26 , high temperature in refluxing solvents 27 and silica sulfuric acid 28 . However, many of these methods have some drawbeaks such as use of expensive catalyst, low yields of the products, tedious procedure, harsh reaction conditions and difficult work-up.…”

Ionic Liquids-Prompted Synthesis of Biologically Relevant Five- and Six-Membered Heterocyclic Skeletons

“…Vijayakumar et al [188] used 10 mol% [EMIM][OAc] as catalyst for one-pot, three-component reaction of 1,4-dihydropyridines 96 from aryl aldehydes, ethyl acetoacetate/acetylacetone, and ammonium acetate under sonication at RT (Scheme 50). The methodology was appeared to be advantageous in terms of higher yield and short reaction period at RT.…”

Progress in Synthesis of 1,4-Dihydropyridines

“…2011 年, Reddy 等 [30] 以离子液体 1-乙基-3-甲基咪唑 乙酸([EMIM]OAc)作为溶剂和催化剂进行 Hantzsch 反 应研究, 在室温下超声辅助以高达 97%的产率合成了一 系列对称的 1,4-DHPs (Eq. 4).…”