One-pot four-component reaction for convenient synthesis of functionalized 1-benzamidospiro[indoline-3,4'-pyridines]

Abstract

SummaryThe one-pot four-component reaction of benzohydrazide (2-picolinohydrazide), acetylenedicarboxylate, isatins and malononitrile (ethyl cyanoacetate) with triethylamine as base catalyst afforded functionalized 1-benzamidospiro[indoline-3,4'-pyridines] in good yields. 1H NMR spectra indicated that an equilibrium of cis/trans-conformations exist in the obtained products.

New Organocatalytic Asymmetric Synthesis of Highly Substituted Chiral 2-Oxospiro-[indole-3,4′- (1′,4′-dihydropyridine)] Derivatives

“…Thus, combining the interest and biological importance of spirooxindoles and 1,4-dihydropyridines and the search for new analogues with novel synergic properties, together with the increasing concern for sustainability, which makes essential the continuous search for new efficient catalytic procedures, encouraged us to explore a new route for the asymmetric synthesis of 2-oxospiro-[indole-3,4′-(1′,4′-dihydropyridine)] via asymmetric organocatalysis [29,30,31,32,33,34].…”

First Organocatalytic Asymmetric Synthesis of 1-Benzamido-1,4-Dihydropyridine Derivatives

“…Related to our work reported herein, we must remark that Yan and co-workers previously published two interesting racemic versions using benzohydrazides 3 , instead of anilines, in two concomitant multicomponent processes to obtain 1-benzamidospiro[indoline-3,4′-pyridines] 4 [ 18 ] or benzamido-1,4-dihydropyridines 5 [ 19 ] ( Scheme 2 ).…”

“… Synthesis of highly substituted benzamidospiro[indoline-3,4′-pyridines] 4 [ 18 ] and benzamido-1,4-dihydropyridines 5 [ 19 ]. …”

(Cu/NCNTs): a new high temperature technique to prepare a recyclable nanocatalyst for four component pyridine derivative synthesis and nitroarenes reduction

“…The synthetic approach for pyridine derivatives has thus far been studied using the three component Hantzsch type synthesis and four component approach. The work to date in this regard includes the use of SnCl 2 Á2H 2 O, 19 p-TsOH, 20 piperidine, 21 tri-ethylamine 22 and FeCl 3 23 as catalysts. All the earlier methods assure a good synthetic yield with a variety of starting materials but at the same time all involve homogeneous conditions and thus do not meet the standards of sustainable technology.…”