Abstract: A rhenium complex, [ReBr(CO)3(thf)]2, catalyzed insertion of terminal alkynes into a C–H bond of active methylene sites of 1,3-dicarbonyl compounds. When a catalytic amount of isocyanide or molecular sieves was added to the reaction mixture, the reaction course changed markedly, and insertion of alkynes into a C–C single bond between αand β-positions of cyclic and acyclic β-keto ester...

The primary role of yeast Ara1, previously mis-annotated as a D-arabinose dehydrogenase, is to catalyze the reduction of a variety of toxic α,β-dicarbonyl compounds using NADPH as a cofactor at physiological pH levels. Here, crystal structures of Ara1 in apo and NADPH-complexed forms are presented at 2.10 and 2.00 Å resolution, respectively. Ara1 exists as a homodimer, each subunit of which ado...

Atmospheric Chemistry and Physics Discussions This discussion paper is/has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP if available. Abstract We used chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS) to characterize secondary organic material formed by methylglyoxal with ...

Hyperglycemia is the most important factor for the onset and progress of diabetic complications. A growing body of evidence indicates that the increase in reactive carbonyl intermediates such as methylglyoxal (MG) is a consequence of hyperglycemia in diabetes. Several studies have shown that higher levels of MG are present in diabetic patients' plasma compared to non-diabetics. Glyoxal (GO) and...

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of 1,3-dicarbonyl compounds, Aromatic and aliphatic aldehydes, and urea or thiourea in the presence of catalytic amount of Brønsted acidic ionic liquid 3-methyl-1-sulfonic acid imidazolium chloride {[Msim]Cl} under thermal solvent-free conditions reacted easily to afford the co...

A highly practical and efficient preparation of pyrano[3,2-c]pyridone and pyrano[3,2-c]quinoline derivatives was developed via an ionic liquid mediated and promoted multi-component reaction of malononitrile, aldehyde, and 4-hydroxyquinolin-2(1H)-one or 4-hydroxy-6-methylpyridin-2(1H)-one. The combinatorial syntheses were achieved for the first time without applying extra activation energy at am...

A domino propargylation/furanylation (intramolecular exo-dig-cyclization)/benzannulation reaction of 2,4-diyn-1-ols with 1,3-dicarbonyl compounds has been developed for the first time. This provides a novel and effective method preparation aryl/heteroaryl-fused benzofurans from easily accessible starting materials in single step. The methodology was extended to pyrrolyl-benzannulation obtain in...

A diastereoselective and enantioselective construction of 2,3-disubstituted 1,4-dicarbonyl compounds is reported. Nishiyama's RuPhebox complex (2.0 mol% catalyst loading) serves as a chiral Lewis acid in conjunction with BrCCl3 base for the oxidative homocoupling 2-acyl imidazoles via stereocontrolled reaction intermediate Ru enolates situ brominated imidazoles. Cleavage achiral imidazole auxil...

1,3-Dibromo-5,5-dimethylhydantoin (DBH) and benzyltriphenylphosphoniumtribromide (BTPTB) were used as efficient catalysts for the promotion of the synthesis of 1,8-dioxo-octahydroxanthene derivatives (DOXOs) via a one-pot three component condensation of aldehydes and cyclic 1,3-dicarbonyl compounds in the absence of solvent.