An enzymatic strategy for the preparation of optically pure α-alkyl-α,β-dihydroxyketones is reported. Homo- and cross-coupling reactions of α-diketones catalyzed by acetylacetoin synthase (AAS) produce a set of α-alkyl-α-hydroxy-β-diketones (30-60%, ee 67-90%), which in turn are reduced regio-, diastereo-, and enantioselectively to the corresponding chiral α-alkyl-α,β-dihydroxyketones (60-70%, ...

An efficient and mild synthesis of quinoxalines in cludingcyclo-condensation of 1, 2-phenylenediamine and 1, 2-diketonesin the presence of1mol% catalytic amount of SnO2 nanoparticles (1 mol%) in water at room temperature is established. On the whole, this study introduced at this point is substantial in terms of using water as solvent, low reaction time (5 to 10 minutes), high yields...

In this context, (Caffeine)(tetrahydroborato)zinc complex as white stable reducing agents [Zn(BH 4 ) 2 (caf)], has been prepared by complexation of one equimolar amounts of zinc tetrahydroborate and one equimolar amounts of caffeine at room temperature. Also, [Zn(BH 4 ) 2 (caf) ]has been used for reduce of a variety of carbonyl compounds such as aldehydes, ketones, α, βunsaturated carbonyl comp...

An intriguing new Wacker-type oxidation of alkynes catalyzed by PdBr(2) and CuBr(2) is described, which opens an efficient access to 1,2-diketones using molecular oxygen. Under the optimized conditions, a variety of alkynes, including diarylalkynes, arylalkylalkynes, and dialkylalkynes, were compatible substrates in this transformation. The mechanism of this reaction was preliminarily investiga...

2-Acyl-1,3-indandiones attracted the interest of chemists as early as forty years ago, since some of them exhibited remarkable physiological, in particular anticoagulant, properties and found use in practice as rodenticides [1—3]. Their chemical properties, however, have been scarcely studied. It is known for example that they exist in a diketoenol form. Nevertheless, existence of two struc­ tu...

Quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of O-aminoarylketones and carbonyl compounds utilizing niobium (V) chloride / polyethylenglycole(NbCl5.PEG) and niobium(V)chloride (NbCl5) as available and inexpensive catalysts. The quinoline derivatives were prepared in glycerol, an excellent solvent in terms of environmental impact, with hig...

We have discovered new characteristics of D-erythrulose reductase, namely, that it can catalyze reduction of not only D-erythrulose but also such diketones as diacetyl. These substrates have a common structure with two neighboring carbonyls possibly in s-cis plane structure, showing that the enzyme may rigorously distinguish between substrates and other compounds. D-Erythrulose reductase was pr...

Over the last decade, concerns have been raised about potential respiratory health effects associated with occupational exposure to the flavoring additives diacetyl and 2,3-pentanedione. Both of these diketones are also natural components of many foods and beverages, including roasted coffee. To date, there are no published studies characterizing workplace exposures to these diketones during co...