sulfonated polystyrene/montmorillonite nanocomposite (ommt/ps-so3h) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. the catalyst was characterized by xrd, sem, tg, bet and ft-ir techniques. this method has advantages of high yi...

Abstract The study includes preparation and characterisation of a new Mannich -β-amino carbonyl namely: (2R)-4-methyl-2-((S)(phenylamino)(p-tolyl)methyl)cyclohexan-1-one. was achieved from the reaction 4-methylcyclohexan-1-one aniline with 4-methylbenzaldehyde in 1:1:1 mole ratio, respectively. Calcium chloride used as catalyst ethanol medium. A range physico-chemical tools were to charcteris i...

Mannich reaction was applied between 4-fluorobezaldehyde, selected acetophenone and several anilines, catalyzed by silica sulfuric acid for the synthesis of β-amino carbonyl derivatives. Reaction time and yield of the products depended on the nature of acetophenone and aniline subsituents. Using aliphatic amines instead of aromatic amines under same reaction conditions, afforded aldol condensat...

A short synthetic sequence leading to the formation of the C,D,E-ring subunit of the Aspidosperma alkaloids is reported. This route is based on a ring fragmentation/intramolecular azomethine ylide 1,3-dipolar cycloaddition reaction sequence that gives the desired tricyclic product as a single diastereomer. A γ-amino-β-hydroxy-α-diazo carbonyl compound is shown to fragment in the presence of a L...

BACKGROUND Lipofuscin (LF) is formed during lipid peroxidation and sugar glycosylation by carbonyl-amino crosslinks with biomacrolecules, and accumulates slowly within postmitotic cells. The environmental pollution, modern dietary culture and lifestyle changes have been found to be the major sources of reactive carbonyl compounds in vivo. Irreversible carbonyl-amino crosslinks induced by carbon...

Streptozotocin (STZ) (2-deoxy-2-({[methyl(nitroso)amino]carbonyl}amino)-β-D-glucopyranose) is a naturally occurring diabetogenic compound, produced by the soil bacterium streptomyces achromogenes, that exhibits broad spectrum of antibacterial properties. Streptozotocin functions as a DNA synthesis inhibitor in both bacterial and mammalian cells. In mammalian cells, the actual mechanism and meta...

Oxidative cleavage of alkenes is a widely employed process allowing oxyfunctionalization to corresponding carbonyl compounds. Recently, a novel biocatalytic oxidative alkene cleavage activity on styrene derivatives was identified in TM1459 from Thermotoga maritima. In this work we engineered the enzyme by site-saturation mutagenesis of active site amino acids to increase its activity and to bro...

Diazo compounds, boranes, and acyl imines undergo a three-component Mannich condensation reaction under catalyst-free conditions to give the anti β-amino carbonyl compounds in high diastereoselectivity. The reaction tolerates a variety of functional groups, and an asymmetric variant was achieved using the (-)-phenylmenthol as chiral auxiliary in good yield and selectivity. These β-amino carbony...

An approach to β-D-2-aminotalose- and β-D-2-aminoidose-configured carbohydrate mimetics bearing a phenyl substituent is described. Unnatural divalent rigid p-terphenyl-linked C-aryl glycosides with 2.0 nm dimension are available using Suzuki cross-couplings. The key compound, a p-bromophenyl-substituted 1,2-oxazine, was prepared by a stereoselective [3 + 3]-cyclization of a D-isoascorbic acid-d...

The structural motif of α,α-difluoro-substituted carboxyl and carbonyl groups with hydroxy- or amino-substituents at the stereogenic carbon in β-position is found frequently drugs biologically active compounds. A straightforward method for obtaining those targets high enantiomeric purity given by asymmetric difluoro-Reformatsky imino-difluoro-Reformatsky reactions that lead to α,α-difluorinated...