15948-53-5Relevant academic research and scientific papers
Water assisted and choline chloride-dimethylurea deep eutectic salts as catalyst towards the attractive reaction of indole, benzaldehyde, and malononitrile
Ruan, Hongli,Lv, Yue,Yu, Shijun,Lv, Chengwei,An, Yue
, p. 1266 - 1274 (2018/08/06)
The condensation of indole, benzaldehyde, and malononitrile was relatively rigorous compared with other Yonemitsu type reaction. We described a strategy using catalytic amount of choline chloride-dimethylurea deep eutectic salts as cheap and safe accelerator. We also found that introducing right amount of water in reaction system was crucial. This method tolerates variations in all three components to get desired 3-substituted indoles in satisfactory yields.
Palladium-catalyzed diastereo- and enantioselective formal [3 + 2]-cycloadditions of substituted vinylcyclopropanes
Trost, Barry M.,Morris, Patrick J.,Sprague, Simon J.
supporting information, p. 17823 - 17831,9 (2012/12/12)
We describe a palladium-catalyzed diastereo- and enantioselective formal [3 + 2]-cycloaddition between substituted vinylcyclopropanes and electron-deficient olefins in the form of azlactone- and Meldrums acid alkylidenes to give highly substituted cyclopentane products. By modulation of the electronic properties of the vinylcyclopropane and the electron-deficient olefin, high levels of stereoselectivity were obtained. The remote stereoinduction afforded by the catalyst, distal from the chiral pocket generated by the ligand, is proposed to be the result of a new mechanism invoking the Curtin-Hammett principle.
Palladium-catalyzed diastereo- and enantioselective formal [3 + 2]-cycloadditions of substituted vinylcyclopropanes
Trost, Barry M.,Morris, Patrick J.,Sprague, Simon J.
supporting information, p. 17823 - 17831 (2013/01/15)
We describe a palladium-catalyzed diastereo- and enantioselective formal [3 + 2]-cycloaddition between substituted vinylcyclopropanes and electron-deficient olefins in the form of azlactone- and Meldrums acid alkylidenes to give highly substituted cyclopentane products. By modulation of the electronic properties of the vinylcyclopropane and the electron-deficient olefin, high levels of stereoselectivity were obtained. The remote stereoinduction afforded by the catalyst, distal from the chiral pocket generated by the ligand, is proposed to be the result of a new mechanism invoking the Curtin-Hammett principle.
Synthesis of zwitterionic salts of pyridinium-meldrum acid and barbiturate through unique four-component reactions
Wang, Qi-Fang,Hui, Li,Hou, Hong,Yan, Chao-Guo
supporting information; experimental part, p. 260 - 265 (2010/08/05)
An efficient synthetic procedure for the preparation of the unusual charge-separated pyridinium-Meldrum acid and N,N-dimethylbarbiturate acid zwitterionic salts was developed though a unique one-pot fourcomponent reaction involving pyridine, aromatic aldehyde, Meldrum acid or N,N-dimethylbarbituric acid, and p-nitrobenzyl bromide in acetonitrile. By varying combinations of four components involving nitrogencontaining heterocycles, we conveniently established reactiveα-halomethylene compounds, aldehydes and β-dicarbonyl compounds a library of zwitterionic salts.
A general and practical preparation of alkylidene Meldrum's acids
Dumas, Aaron M.,Seed, Adam,Zorzitto, Alexander K.,Fillion, Eric
, p. 7072 - 7074 (2008/03/11)
Although many methods have been reported for the Knoevenagel condensation of aldehydes and Meldrum's acid, most are not general or use unconventional reagents and conditions. We have found that alkylidene Meldrum's acids form readily in benzene solution u
Modular synthesis of tetrahydrofluorenones from 5-alkylidene Meldrum's acids
Fillion, Eric,Dumas, Aaron M.,Hogg, Sylvia A.
, p. 9899 - 9902 (2007/10/03)
The one-pot synthesis of tetrahydrofluorenones, the core 6-5-6 tricyclic structural motif found in norditerpenoid natural products, from alkylidene Meldrum's acids via thermal Diels-Alder/BF3·OEt 2-catalyzed Friedel-Crafts acylation
One Pot Synthesis of Monoalkylated and Mixed, Dialkylated Meldrum's Acid Derivatives
Desai, Uday V.,Pore,Mane,Solabannavar,Wadgaonkar
, p. 25 - 32 (2007/10/03)
A simple one pot method, involving sequential Knoevenagel condensation of Meldrum's acid with aromatic aldehydes, conjugate reduction of ylidene Meldrum's acid using sodium borohydride followed by alkylation, to prepare mixed dialkylated derivatives of Meldrum's acid is described.
Nucleophilic Addition to Olefins. 21. Substituent and Solvent Effects on the Reaction of Benzylidene Meldrum's Acids with Piperidine and Morpholine
Bernasconi, Claude F.,Panda, Markandeswar
, p. 3042 - 3050 (2007/10/02)
Rate (k1) and equilibrium constants (K1) for piperidine and morpholine addition to benzylidene Meldrum's acid (BMA) and substituted BMA's (Z=4-NO2, 3-Cl, 4-CN, 4-OMe, 4-NMe2, 4-NEt2) were determined in water and in 50percent, 70percent, and 90percent aqueous Me2SO.The equilibrium for addition is highly favorable, with K1 values (piperidine) as high as 7.8*107M-1, which is the highest value measured in a series of olefins of the type PhCH=CXY.The rates are also quite high (k1 up to 2.1*106M-1s-1), indicating a relatively high intrinsic rate constant (k0=k1 for K1=1) which ranks BMA second among seven PhCH=CXY-type olefins with respect to kinetic reactivity.This ranking is "reasonable" based on a correlation between k0 for nucleophilic addition to PhCH=CXY and k0 for deprotonation of carbon acids of the type CH2XY.βnucn (d log k1/ d log K1, variation of amine) is very amall, particularly in aqueous solution.This result appears to be part of a trend toward lower βnucn values with increasing thermodynamic stability of the adducts of PhCH=CXY. αnucn (d log k1/ d log K1, variation of Z) is significantly larger than βnucn, implying a substantial imbalance in these reactions.However, after correction of αnucn for the effect of the developing positive charge on the amine nitrogen the remaining "true" imbalance is quite small.The small imbalance as well as the high k0 value are consistent with the Meldrum's acid anion deriving most of its exceptional stability from its bislactone structure rather than from resonance.Strong ?-donor substituents (4-NMe2, 4-NEt2) have a strong stabilizing effect on the olefin, leading to a large reduction in K1.Contrary to expectations based on the principle of nonperfect synchronization (PNS), this resonance effect does not lead to a strong reduction of the intrinsic rate constant, probably because the polarization in the olefin (Me2N+=C6H4+CHC(COO)2-C(CH3)2) helps in partially offsetting the PNS effect caused by delayed development of resonance on the carbanionic side of the adduct
