52279-26-2Relevant articles and documents
Chemoenzymatic synthesis of aroma active 5,6-dihydro- and tetrahydropyrazines from aliphatic acyloins produced by baker's yeast
Kurniadi, Toshinari,Bel Rhlid, Rachid,Fay, Laurent-Bernard,Juillerat, Marcel-Alexandre,Berger, Ralf Guenter
, p. 3103 - 3107 (2007/10/03)
Twenty-five acyloins were generated by biotransformation of aliphatic aldehydes and 2-ketocarboxylic acids using whole cells of baker's yeast as catalyst. Six of these acyloins were synthesized and tentatively characterized for the first time. Subsequent chemical reaction with 1,2-propanediamine under mild conditions resulted in the formation of thirteen 5,6-dihydropyrazines and six tetrahydropyrazines. Their odor qualities were evaluated, and their odor thresholds were estimated. Among these pyrazine derivatives, 2-ethyl-3,5-dimethyl-5,6-dihydropyrazine (roasted, nutty, 0.002 ng/L air), 2,3-diethyl-5-methyl-5,6-dihydropyrazine (roasted, 0.004 ng/L air), and 2-ethyl-3,5-dimethyltetrahy-dropyrazine (bread crustlike, 1.9 ng/L air) were the most intensive-smelling aroma active compounds.
A direct conversion of vic-diols into 1,2-diketones with aqueous hydrogen peroxide catalyzed by peroxotungstophosphate (PCWP)
Iwahama, Takahiro,Sakaguchi, Satoshi,Nishiyama, Yutaka,Ishii, Yasutaka
, p. 1523 - 1526 (2007/10/02)
α-Hydroxy ketones and vic-diols were successfully oxidized to the corresponding diketones with acqueous hydrogen peroxide in the presence of a catalytic amount of peroxotungstophosphate (PCWP). This method provides a straightforward route of 1,2-diketones which are difficult to prepare by conventional oxidation of vic-diols.
The acyloin reaction using tethered diesters
Daynard, Tim S.,Eby, Paul S.,Hutchinson, John H.
, p. 1022 - 1028 (2007/10/02)
A study of the intramolecular acyloin condensation using diesters tethered by their alkoxide groups was undertaken.The goal was to provide a method for optimizing the yield of mixed acyloin products from the reaction of two different esters by utilizing tethered dissimilar esters as substrates.The results of the study show that the yield of the acyloin condensation is dependant on the tether length.Tethers of 8 and 14 carbons in length give yields comparable to those obtained from an intermolecular control reaction while shorter tethers give reduced yields of product.However, the use of mixed tethered diesters and a crossover experiment between two different tethered substrates provides a statistical distribution of products.These observations have been interpreted as resulting from a fragmentation of the initially formed radical anion intermediate that destroys the tethered nature of the substrate(s).