Aqueous hydrotrope solution as a safer medium for microwave enhanced hantzsch dihydropyridine ester synthesis

Khadilkar, Bhushan M.; Gaikar, Vilas G.; Chitnavis, A. A.

doi:10.1016/0040-4039(95)01680-g

Cited by 126 publications

(51 citation statements)

References 12 publications

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“…While the Biginelli reaction has been limited to aromatic and heteroaromatic aldehydes, the Hantzsch reaction can also convert aliphatic aldehydes. The CH-acidic component can be varied over a wide range in the same way [59]. Investigations on the Hantzsch reaction carried out in the microwave field are documented; however, the research was either limited to reactions in household microwave ovens without reliable documentation of the reaction conditions [60±62] or the reaction was carried out on a very small 1-mmol scale [63].…”

Section: Hantzsch Reactionmentioning

confidence: 99%

Microwave‐Assisted Chemical Reactions

Nüchter

Müller

Ondruschka³

et al. 2003

Chem Eng & Technol

141

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This article reviews the state of the art of microwave-assisted reactions and the influence of microwaves on mass and heat transfer. The heating behavior of representative test reactions and single substances is compared for heating with microwaves and thermal energy. Similarities and differences between convective heating and dielectric irradiation methods are discussed with regard to the yield, the selectivity, and the enantiomeric purity of the reaction products. Furthermore, prevailing problems related to the scale-up of microwave-assisted reactions are discussed considering the energy absorption of the substances and mixtures to be heated, and their dependence on the energy consumption and the amount of substance.

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Section: Hantzsch Reactionmentioning

confidence: 99%

Microwave‐Assisted Chemical Reactions

Nüchter

Müller

Ondruschka³

et al. 2003

Chem Eng & Technol

141

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“…However, this method has several disadvantages including longer reaction times, the us of an excess amount of organic solvent, lower product yields and harsh refluxing conditions. Since the method of Hantzsch was described more than a use century ago [17][18][19] , several efficient methods have been developed for the synthesis of 1, 4-dihydropyridines that involve the use of a microwave [20][21][22] , ionic liquids [23][24] , high temperatures in refluxing solvent [25][26][27][28][29][30][31][32][33][34][35] , TMSCl-NaI 36 and metal triflates 37 . However, the use of high temperatures, expensive metal precursors and the resultant longer reaction times limit these methods.…”

Section: Introductionmentioning

confidence: 99%

Al2(SO4)3 IS AN EFFICIENT AND MILD ACID CATALYST FOR THE ONE-POT, FOUR-COMPONENT SYNTHESIS OF POLYHYDROQUINOLINE

Kulkarni¹

2014

J. Chil. Chem. Soc.

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Aluminium sulfate has mild acidity, yet the acidity of aluminium sulfate is not taken advantage of in organic synthesis. Here, we utilized aluminium sulfate for the first time in a multicomponent reaction for the synthesis of polyhydroquinoline. A four-component one-pot synthesis of polyhydroquinoline was carried out by condensing dimedone, aromatic aldehyde, ethyl acetoacetate, and ammonium acetate using a catalytic amount of aluminium sulfate (10%) refluxed in ethanol. The present protocol using aluminium sulfate a mild solid catalyst has several merits, such as low cost, high yield, and shorter reaction time, with no byproducts.

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“…The current work was commenced for the fundamental study of the global character of hydrotropes in the selective separation of a component from mixtures via solubilization and precipitation techniques [11][12][13][14][15][16][17] . With particular attention on both the theoretical understanding of the mechanistic action and the experimental studies which demonstrate the utility of hydrotropes in the separation of commercially prominent mixtures [18][19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Solubility and Reflection of Hydrotropy Technique in the Segregation of of m/p-Aminonitrobenze

Dhinakaran¹,

Morais²,

Gandhi³

2012

Chem Sci Trans

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Abstract:The aqueous solubilities of m/p -amino nitrobenzene in different concentrations (0-3.0 mol/L) of hydrotropes such as sodium benzoate, sodium saccharin, dimethyl benzamide at different system temperatures (303 K to 333 K) were studied. The percentage extraction (%E) of m-amino nitrobenzene from m/p -amino nitrobenzene mixture increases with an increase in hydrotrope concentration. A minimum hydrotrope concentration (MHC) in the aqueous phase was required to initiate the significance of the %E of m-amino nitrobenzene. Percentage extraction (%E) is the ratio of moles of m -amino nitrobenzene extracted in presence and absence of a hydrotrope. The sensitivity and feasibility of the proposed process are examined by carrying out solubilization and equilibrium precipitation experiments with the mixtures of various compositions. The effectiveness of hydrotropes was measured in terms of Setschenow constant Ks and reported for all hydrotropes used in this study and determination of aggregation behavior of all hydrotropes were also studied.

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Aqueous hydrotrope solution as a safer medium for microwave enhanced hantzsch dihydropyridine ester synthesis

Cited by 126 publications

References 12 publications

Microwave‐Assisted Chemical Reactions

Microwave‐Assisted Chemical Reactions

Al2(SO4)3 IS AN EFFICIENT AND MILD ACID CATALYST FOR THE ONE-POT, FOUR-COMPONENT SYNTHESIS OF POLYHYDROQUINOLINE

Enhanced Solubility and Reflection of Hydrotropy Technique in the Segregation of of m/p-Aminonitrobenze

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