Aryl Glyoxals Research Articles

A New Three-Component Coupling reaction of Aryl Glyoxal, Malononitrile, and 4-Hydroxy Coumarin Catalysed by Recyclable Tio2 nanoparticles

Aryl glyoxals reacted with malononitrile and 4-hydroxycoumarin in the presence of a catalytic amount of TiO2 nanoparticles to give a hitherto unknown family of pyranochromenes in up to 80% yield. This new three-component reaction yielded some novel pyrano[3,2-c]chromene-5-ones containing an aroyl substituent. Using a recyclable and safe catalyst along with a green solvent system made the process eco-friendly and economic.

Synthesis of 2-Aroyl(Hetaroyl)-1-Hydroxy- Imidazoles by the Interaction of Alkyl-Aromatic α-Hydroxyaminooximes with Aryl(Hetaryl)Glyoxals

The interaction of alkylaromatic and alkylheteroaromatic α-hydroxyaminooximes with aryl(hetaryl)-glyoxals hydrates produced a new series of 2-aroyl(hetaroyl)-5-aryl(hetaryl)-1-hydroxy-4-methylimid-azoles. The X-ray structural data for 2-benzoyl-5-(4-fluorophenyl)-1-hydroxy-4-methylimidazole are presented.

Convenient on water synthesis of novel derivatives of dicoumarol as functional vitamin K depleter by Fe3O4 magnetic nanoparticles

The Fe3O4 nanoparticles were successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), and transmission electron microscopy (TEM). The magnetic property of the prepared nanoparticles was investigated by magnetization analysis and the measured magnetization of NPs was found to be considerably lower than the values measured from bulk magnetite. The catalytic efficiency of the prepared nanoparticles was subsequently investigated as a magnetically recyclable and safe catalyst for the green synthesis of new dicoumarols via the one-pot condensation of 4-hydroxycoumarin with aryl glyoxals on water. Catalyst loadings can be as low as 2mol% to give good yields of the corresponding products. This present method has many advantages, such as the high product yield, avoidance of toxic organic solvents, and simple work-up procedure.

Iron(II,III) oxide nanoparticle-catalyzed selective synthesis of unknown dihydropyrano[c]chromenes under green conditions

An efficient one-pot, three-component condensation reaction between 4-hydroxycoumarin, aryl glyoxals, and malononitrile for the synthesis of new dihydropyrano[c]chromenes is reported. The reactions were efficiently catalyzed by magnetically recyclable Fe3O4 nanoparticles to afford the desired products in good to excellent yields. The method is simple and completely in accordance with green chemistry principles.

Synthesis of new 4-aroyl-pyrano[c]chromenes via a one-pot, three-component reaction based on aryl glyoxals

A new library of pyrano[c]chromenes containing an aroyl group has been synthesized by a novel multicomponent process involving the reaction of various aryl glyoxals with 4-hydroxycoumarin and malononitrile. The reactions were catalyzed efficiently by ammonium dihydrogen phosphate to yield the desired products in good to excellent yields.

ChemInform Abstract: A Highly Efficient and Enantioselective Intramolecular Cannizzaro Reaction under TOX/Cu(II) Catalysis.

An asymmetric intramolecular Cannizzaro reaction of aryl and alkyl glyoxals with alcohols has been realized with an unprecedented high level of enantioselectivity, on the basis of a newly developed congested TOX ligand and a gradual liberation protocol of active glyoxals from glyoxal monohydrates. Preliminary results suggested a mechanism of enantioselective addition of alcohols to glyoxals contributing most to the stereoselectivity, other than by the dynamic kinetic resolution of hemiacetal intermediates.

Simple Method for the Synthesis of Aryl(Furfuryl)Glyoxals

Furan derivatives containing reactive functional groups are useful structural units for the synthesis of different classes of chemical compounds [1-6]. Even such simple furans as phenacylfurans [7] containing one carbonyl group can be used in the preparation of cyclopentenones [8] which are the basic structural fragments in prostaglandins. In this connection, the development of methods for the synthesis of novel, functionalized furan compounds is a current problem. To our surprise aryl(furfuryl)glyoxals (which might be expected to have interesting reactivity) have proved to be unknown compounds. In this work we report the synthesis of these aryl(furfuryl)glyoxals. A Knoevenagel condensation of the readily available phenacylazides 1a-d [9, 10] with the furfurals 2a,b gives the azidochalcones 3a-e [11]. Subsequent treatment with triethyl phosphite and hydrochloric acid gives the target compounds 4a-e.

A Facile and Expeditious One-Pot Synthesis of α-Keto-1,3,4-oxadiazoles

An efficient and high-yielding protocol for the preparation of α-keto-1,3,4-oxadiazoles has been developed. Formation of α-keto-1,3,4-oxadiazoles involves the 2-iodoxybenzoic acid/tetraethylammonium bromide mediated oxidative cyclization of hydrazide-hydrazones generated in situ from the reaction of aryl glyoxal and hydrazides. This one-pot protocol is reasonably general for the preparation of α-keto-1,3,4-oxadiazoles under mild conditions in short reaction times.

Convenient access to novel functionalized pyrazino[1,2-b]isoquinolin-6-one and diazepino[1,2-b]isoquinolin-7-one scaffolds via the Cushman multicomponent reaction followed by post-condensation

Post-multicomponent reaction modifications of Cushman reaction-derived 1,2,3,4-tetrahydroisoquinolin-4-carboxylic acids turned out to be a surprisingly underdeveloped strategy in scaffold-oriented synthesis. In this Letter, we describe a concise synthesis of hitherto unreported pyrazino- and diazepino-fused isoquinolones in two chemical operations. The synthesis involves the use, for the first time, of aryl glyoxals as carbonyl components for the Cushman multicomponent reaction.

Regiospecific strategies for the synthesis of novel dihydropyrimidinones and pyrimidopyridazines catalyzed by molybdate sulfuric acid

The one-pot reactions of aryl glyoxals with acetylacetone and urea using molybdate sulfuric acid (5mol%) lead to the novel functionalized 5-acetyl-4-(aryloyl)-3,4-dihydropyrimidinones, which readily undergo the Knorr condensation with hydrazines to produce new pyrimido[4,5-d]pyridazines. The present strategies are in accordance with green chemistry principles through the use of a safe and recyclable catalyst under solvent-free conditions.

Graphene oxide nanosheets as metal-free catalysts in the three-component reactions based on aryl glyoxals to generate novel pyranocoumarins

Graphene oxide (GO) was employed as an efficient and powerful catalyst in one-pot, three-component synthesis of new pyranocoumarins.

Graphene oxide nanosheets promoted regioselective and green synthesis of new dicoumarols

Graphene oxide (GO) was obtained by modified Hummers oxidation of graphite and used as a highly efficient, metal-free, non-oxidative, and recyclable catalyst to promote the condensation of 4-hydroxycoumarin and aryl glyoxals for synthesis of new dicoumarols.

Zinc oxide nanorods: a new application as a powerful catalyst for the green one-pot synthesis of new warfarin analogs

A facile and green synthesis of warfarin analogs was achieved via the one-pot reaction of aryl glyoxal with benzamide and 4-hydroxycoumarins. The reactions were efficiently catalyzed by a small amount of ZnO nanorods (NRs). The present method is highlighted by some features such as, avoidance of solvent, high product yields, and recyclability of the catalyst.

The first practical approach to new pyrimido[4,5-d]pyridazines: novel chemoselective and regioselective reactions

A new three-component condensation of aryl glyoxals, acetylacetone and urea in the presence of a small amounts of tungstate sulfuric acid (TSA) leads to novel functionalized 5-acetyl-4-(aryloyl)3,4-dihydropyrimidinones which these heterocycles can undergo the Knorr condensation with hydrazines to produce new pyrimido[4,5-d]pyridazines in good yields. These approaches are consistent with principles of green chemistry due to some factors, such as the use of a safe and recyclable catalyst under solvent-free conditions.

ChemInform Abstract: Regiospecific Synthesis of Novel Furo[4,5‐c]coumarins in a One‐Pot Reaction.

A new and expedient assembly of an interesting class of amido-substituted furo[4,5-c]coumarins has been successfully achieved through a one-pot sequential coupling and cyclization strategy starting from 4-hydroxycoumarin, aryl glyoxals and benz­amide. All the reactions showed selectivity towards furo[4,5-c]coumarin, instead of the corresponding isoxazolo-substituted coumarins.

ChemInform Abstract: Enantioselective Additions of (Trifluoromethyl)trimethylsilane to α‐Imino Ketones Derived from Aryl Glyoxals.

AbstractAddition of silane (II) to α‐imino ketones in the presence of a cinchona‐based catalyst provides O‐silylated β‐imino alcohols.

Regiospecific Synthesis of Novel Furo[4,5-c]coumarins in a One-Pot Reaction

A new and expedient assembly of an interesting class of amido-substituted furo[4,5-c]coumarins has been successfully achieved through a one-pot sequential coupling and cyclization strategy starting from 4-hydroxycoumarin, aryl glyoxals and benz­amide. All the reactions showed selectivity towards furo[4,5-c]coumarin, instead of the corresponding isoxazolo-substituted coumarins.

Enantioselective additions of (trifluoromethyl)trimethylsilane to α-imino ketones derived from aryl glyoxals

Chemoselective additions of (trifluoromethyl)trimethylsilane to α-imino ketones derived from aryl glyoxals in the presence of a catalytic amount of enantiomerically pure ammonium bromides, derived from Cinchona alkaloids and K2CO3 led to O-silylated β-imino alcohols. Subsequent reduction of these products with NaBH4 gave β-(N-alkyl)amino-α-trifluoromethyl alcohols for which the ee values were 30–71% under optimized conditions. Enantiomeric excesses were determined for the final products on the basis of 1H or 19F NMR spectra registered in the presence of chiral solvating agents.

One-pot synthesis of disubstituted imidazole derivatives from α-azido ketones catalyzed by potassium ethylxanthate

An efficient, novel procedure for the synthesis of new imidazole derivatives from α-azido ketones is described. This reaction proceeds via dimerization of aryl glyoxal imino generated from α-azido ketones in the presence of potassium ethylxanthate as a catalyst. A possible mechanism for the entire sequence is proposed.

A NOVEL AND SIMPLE SYNTHESIS OF SOME NEW AND KNOWN DIBENZO PHENAZINE AND QUINOXALINE DERIVATIVES USING LEAD DICHLORIDE

A simple method for the synthesis of phenazine and quinoxaline derivatives have been developed via a reaction of o-phenylenediamines and 1,2-dicarbonyl compounds or aryl glyoxals in the presence of lead dichloride in ethanol at room temperature. This method has many appealing attributes such as excellent yields, short reaction times, and simple work-up procedure.