Arylglyoxal

Cationic BINAP-palladium and platinum complexes 30a,b can catalyze highly enantioselective cycloaddition reactions of arylglyoxals with acyclic and cyclic... 

Rearrangement of trivalent (5-hexenyl)Co(salen) proceeds via a radical chain process leading to the isomeric cyclopentylmethyl complex.1387 The efficiency with which this rearrangement occurs is dependent on the presence of trace impurities or 02. The selective reaction of alcohols (ROH) with arylglyoxals (ArCOCHO) to give a-aryl-a-hydroxyacetic esters ArCH(0H)C02R is catalyzed by compounds of this family.1388... 

Methods currently available for chemiluminescent detection of nucleic acids are not based on derivatization techniques that directly recognize one of the nucleic acid bases or nucleotides. For chemical derivatization-based chemiluminescent detection, the specific reactivity of alkyl glyoxals and arylglyoxals with adenine or guanine nucleotides has been investigated. 

Acetyl-l-aryl-2-pentene-l,4-diones 65 formed from the reaction of arylglyoxal with 2,4-pentanedione in the presence of BF3 Et20 are converted to tri- and tetra-substituted furans <00TL3149>. 

Faggi et al. describes the synthesis of a 1,6-dihydro-6-oxopyrazine-2-carboxylic acid derivative via the Ugi four-component reaction (Scheme 8) [28]. Arylglyoxals 44, an amine 45, benzoylformic acid 46, and an isocyanide 47 afforded the Ugi intermediate 48, which was cyclized in a [5+1] fashion with ammonium acetate to give the final product 49 in good yields. 

Hydrolysis in acid of compounds assigned the a-cyanoazoacetophenone structures (681) affords arylglyoxal semicarbazones (682). These can be cyclized in hot sodium hydroxide to 5-aryl-l,2,4-triazin-3-ones (683) <02LA(325)129). 

Another synthesis of the butenolide core was reported by the Domling group [54], The reaction between arylglyoxals, isocyanides, and a-diethylphosphonoalkanoic... 

Davidson s synthesis consists of the cydization of a-acyloxyketones with ammonia or ammonium acetate to give 2,4,5-trisubstituted oxazoles. The Passerini reaction between arylglyoxals, carboxylic acids, and isocyanides afforded N-substituted 2-acyloxy-3-aryl-3-oxopropionamides 83 in high yields. Upon heating with an excess of ammonium acetate in acetic acid, compounds 83 were cydized to N,2,4-trisubstituted oxazole-5-carboxamides 84 in fair yields [59]. A large number of a-acyloxy-jS-ketoamides can be prepared by changing the reaction components, so the method provides straightforward access to a variety of oxazole-5-carboxamides (Scheme 2.30). 

The Ugi-4CR provides straightforward access to precursors of the pyrazine ring that are suitable for a Davidson cyclization [72], The reaction between arylglyoxals, amines, isocyanides, and benzoylformic acid in ether afforded adducts 114, which cyclized on treatment with an excess of ammonium acetate in acetic acid to give pyrazine carboxamides 115 (Scheme 2.41). 

Note The following examples employ a 2-aminoacetamide as the N—C—C—N synthon with an alkyl- or arylglyoxal as the C—C synthon. In every case only one product was isolated, usually that arising from condensation of the free amino group with the ketonic carbonyl and the amidic amino group with the aldehydic carbonyl. 

The metal template method is commonly used for the syntheses of metal complexes of ligands derived from the title macrocycles. Mostly, the central ion could not be removed to get a free cyclic ligand thus, there are limited examples of ligand syntheses by this method. C-Aryl cyclen derivatives 74 were prepared using the small Fe3+ ion as a template <1998NJC1359>. Condensation of Fe(m) complex of 2,2,2-tet with arylglyoxals formed imine complexes,... 

An indium trichloride-catalyzed three-component reaction of substituted phenols, an arylglyoxal monohydrate, and /)-toluenesulfonamide has been shown to furnish 2-aryl-3-aminobenzofurans (Equation 121) <2005SL2047>. 

Substituted phenylglyoxals are starting materials for the synthesis of 2-arylquinoxa-lines. Sterically hindered arylglyoxals, e.g. mesitylglyoxal, fail to give quinoxalines and only Schiff bases are formed. ... 

Non-activated dienes react with arylglyoxals and glyoxylate esters in the presence of chiral BINAP-palladium(II) or platinum(II) complexes (Sch. 59) [205]. With glyoxylate esters, ene products are formed competitively. 

Treatment of arylglyoxal monohydrates 1380 with tetrasulfur tetranitride 1381 in dioxane at reflux affords 2-aroyl-5-arylimidazoles 1382 and 2-aroyl-5-aryloxazoles 1383 in 10-31% and 17-32% yields, respectively (Scheme 357) <1999JHC911>. 

R. Bossio and co-workers developed a novel method for the synthesis of tetrasubstituted furan derivatives. The Passerini reaction between arylglyoxals, isocyanides, and cyanoacetic acids led to the formation of A/-substituted 3-aryl-2-cyanoacetoxy-3-oxopropionamides, which in the presence of amine bases underwent a Knoevenagei condensation providing A/-substituted 3-aryl-cyano-2,5-dihydro-5-oxofuran-2-carboxamides. 

Nerdinger, S., Beck, B. New heterocycle synthesis by using bifunctional reactants in multicomponent reaction chemistry the use of arylglyoxals and cinnamaldehyde in the Ugi-4CR and Passerini-3CR. Chemtracts 200Z, 16, 233-237. 

Application of the Davidson oxazole synthesis to products of the Passerini reaction has expanded the usefulness of this well-known route <91LAll07>. The a-acyloxy ketones or a-acyloxy -keto esters employed in the Davidson synthesis are not readily available. However, the use of arylglyoxals as the carbonyl component of the Passerini reaction, along with cyclohexyl isocyanide and carboxylic acids, gives a wide variety of iV-cyclohexyl-2-acyloxy-3-aryl-3-oxopropionamides (151). Reaction of these intermediates with ammonium formate in acetic acid affords A -cyclohexyl-2,4-diaryl-5-oxazolecarboxamides (152) in fair yields (Scheme 69). 

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