SYNTHESIS AND SPECTRAL STUDIES OF SOME NEW [(ALKOXYCARBONYLVINYL)ARYL- AND BENZYLSULFONYLMETHYL] SULFONES

Abstract

Some new 1,1,2-trisubstituted ethylenic sulfones have been prepared by the condensation of aryl- and benzylsulfonylmethylsulfonylacetic acid esters with araldehydes.     

Silica Sulfuric Acid: A Versatile and Reusable Catalyst for Synthesis of Coumarin-3-carboxylic Acids in a Solventless System

Synthesis of substituted coumarin-3-carboxylic acid via Knoevenagel condensation of meldrum's acid with ortho-hydroxyaryl aldehydes in solventless system is described.     

基于5-(2-羧基苯基)吡啶-3-甲酸配体的镍(Ⅱ)和锌(Ⅱ)配位聚合物的合成、晶体结构、催化及抗磨性质

采用水热方法,选用5-(2-羧基苯基)吡啶-3-甲酸配体(H₂cpna)与1,2-二(4-吡啶基)乙烷(dpea)或1,2-二(4-吡啶基)乙烯(dpey)分别与NiCl₂·6H₂O和ZnCl₂在160℃下反应,合成了2个三维配位聚合物{[Ni(μ₃-cpna)(μ-dpea)_0.5]·H₂O}_n (1)和{[Zn(μ₃-cpna)(μ-dpey)_0.5]·H₂O}_n (2),并对其结构、催化和摩擦性质进行了研究。研究表明,在室温条件下化合物2在Knoevenagel缩合反应中显示出较好的催化活性。同时,2在聚α-烯烃合成润滑剂中显示出有效的抗磨性能。     

Preparation of Mg–Al hydrotalcite from the effluent of Friedel–Crafts reaction and its application as a catalyst in Knoevenagel reaction

Abstract

Hydrotalcite containing magnesium and aluminium (Mg–Al HT) with a molar ratio of Mg(II)/Al(III) = 2.5 has been prepared by a co-precipitation method using the effluent of a Friedel–Crafts acylation reaction. The HT was calcined at 500°C and reconstructed with deionized water. The synthesized HT was characterized by XRD and FT-IR spectroscopy and was successfully used as a catalyst in the Knoevenagel reaction of aldehydes and active methylene compounds. The catalyst was found to be reusable.     

Organic Reactions in Ionic Liquids: Ionic Liquid Ethylammonium Nitrate–Promoted Knoevenagel Condensation of Meldrum's Acid With Aromatic Aldehydes

The Knoevenagel condensation of Meldrum's acid with aromatic aldehydes proceeded efficiently in a reusable ionic liquid, ethylammonium nitrate, at room temperature in the absence of any catalyst with high yields.     

A Simple,Efficient and Green Procedure for the Knoevenagel Condensation of Aldehydes with N-Methylpiperazine at Room Temperature under Solvent-Free Conditions

Knoevenagel condensation of aromatic, aliphatic, and heteroaromatic aldehydes with active methylene compounds such as ethylcyanoacetate, malononitrile, and cyanoacetamide proceed very smoothly at room temperature by simply mixing the ingredients together under solvent-free conditions in the presence of N-methylpiperazine in excellent yields of the E-configured products.     

Synthesis of New Iminocoumarins Bearing Parabanic Moieties

The synthesis of novel substituted 3-p-nitro-phenyliminocoumarins and corresponding N-ureaiminocoumarins is described. The condensation of these materials with oxalyl chloride leads to the corresponding N-parabanic iminocoumarins, which have not previously been described, in moderate or good yields and high selectivity. The structures were characterized by Fourier transform infrared, ¹H and ¹³C NMR, and elemental analysis.

Diammonium Hydrogen Phosphate: An Efficient and Versatile Catalyst for the One‐Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives in Aqueous Media

Diammonium hydrogen phosphate was used as a mild, efficient, neutral, and cheap catalyst for the synthesis of various 4H‐benzo[b]pyran derivatives via a one‐pot, three‐component condensation of aromatic aldehydes, active methylene compounds, and dimedone in aqueous media.     

A Mild and Efficient Route to 3-Vinylchromones in Aqueous Micellar Media

A simple, mild, and ecofriendly method has been developed for the synthesis of 3-vinylchromones from 4-oxo-4H-1-benzopyran-3-carboxaldehyde (3-formylchromone) by simple Knoevenagel condensation with various active methylene compounds (AMC) in aqueous micellar media in the presence of catalytic amounts of cetyl trimethylammonium bromide (CTAB) and 1,4-diazabicyclo[2.2.2]octane (DABCO). In the case of malonic acid as AMC, the reaction resulted in formation of only Doebner decarboxylated products under the standard reaction condition. It has been also observed that 3-formylchromone derivatives primarily undergo tandem Knoevenagel and Michael reactions in the presence of > 2 equiv. of ethyl acetoacetate to produce benzophenone derivatives, by opening of pyran ring, as the sole product in good yields.     

Organic Reactions in Ionic Liquids: Ionic Liquid Promoted Knoevenagel Condensation of Aromatic Aldehydes with (2‐Thio)Barbituric Acid

Abstract

The Knoevenagel condensation of aromatic aldehydes with (2‐thio)barbituric acid proceeded efficiently in reusable ionic liquids, EAN, BmimBF₄, and BmimPF₆ at room temperature in the absence of any catalyst with high yields.