- Biotechnological properties of sponges from northeast Brazil: Cliona varians as a Biocatalyst for Enantioselective Reduction of Carbonyl Compounds
-
To research the potential ability of whole marine sponges to act as biocatalysts, this paper describes for the first time the employment of whole Cliona varians sponge in the stereoselective reduction of prochiral α-keto esters and isatin to the corresponding chiral alcohols. The addition of D-fructose, D-glucose or sucrose remarkably increased the conversion ratios and stereoselectivities by this marine sponge. Furthermore, in the presence of D-glucose and D-maltose, the reduction of isatin by C. varians afforded the corresponding 3-hydroxyindolin-2-one with high conversions (85-90percent) and good enantioselectivities (60-74percent). These results showed that the marine sponge presents great potential to be used as biocatalyst for stereoselective reduction of carbonyl compounds.
- Riatto, Valéria B.,Victor, Mauricio M.,Sousa, Jaqueline F.,Menegola, Carla
-
p. 149 - 157
(2018/12/13)
-
- Combination strategy using pure enzymes and whole cells as biocatalysts for the preparation of 2-hydroxyesters and lactones from 2-oxoglutaric acid
-
An innovative combination strategy that uses pure enzymes and whole microbial cells in the same process was used to prepare enantiomerically pure 3-carboxyalkyl-γ-butyrolactones and several alkyl esters of 2-hydroxyglutarate from 2-oxoglutaric acid. An innovative combination strategy that uses pure enzymes and whole microbial cells in the same process was used to prepare enantiomerically pure 3-carboxyalkyl-γ-butyrolactones and several alkyl esters of 2-hydroxyglutarates from 2-oxoglutaric acid. The method involves two consecutive biocatalytic steps. The first step, which converts the 2-oxoglutaric acid into the corresponding dialkyl esters, was catalyzed by a lipase. Then in the second step, by microbial reduction of the dialkyl-2-oxoglutarates, it is possible to obtain 3-carboxyalkyl-γ- butyrolactones or 2-hydroxyesters depending on the length of the chain in the alkyl moiety of the esters and on the fresh or lyophilized status of the cells.
- Rustoy, Eduardo M.,Pereyra, Elba N.,Moreno, Silvia,Baldessari, Alicia
-
p. 3763 - 3768
(2007/10/03)
-
- Synthesis of (S)-3-heteroaryl-2-hydroxy-1-propyl benzoates by 'ring switching' methodology
-
(S)-5-Benzoyloxymethyl-3-[(E)-(dimethylamino)methylidene]tetrahydrofuran-2- one (6), prepared in 5 steps from L-glutamic acid (1), was used as precursor in a one step 'ring switching' synthesis of (S)-2-hydroxy-3-heteroaryl-1-propyl benzoates 13-18, 23, 24. In the reaction of 6 with 2-aminopyridine (21) and 2-amino-4,6-dimethylpyrimidine (22) the corresponding dimethylamine substitution products (25, 26) were obtained.
- Mihelic, Damjana,Jakse, Renata,Svete, Jurij,Stanovnik, Branko,Grdadolnik, Simona Golic
-
p. 1307 - 1312
(2007/10/03)
-
- Asymmetric synthesis of alkyl 5-oxotetrahydrofuran-2-carboxylates by enantioselective hydrogenation of dialkyl 2-oxoglutarates over cinchona modified Pt/Al2O3 catalysts
-
The first direct asymmetric synthesis of chiral alkyl 5- oxotetrahydrofuran-2-carboxylates (up to 96% ee), which are important building blocks in the synthesis of natural products by heterogeneous cinchona-modified Pt-catalyzed hydrogenation of α-ketoglutaric acid esters and subsequent cyclization of hydroxy esters is described.
- Balazsik, Katalin,Szoeri, Kornel,Felfoeldi, Karoly,Toeroek, Bela,Bartok, Mihaly
-
p. 555 - 556
(2007/10/03)
-
- Enantiomerically pure tetrahydro-5-oxo-2-furancarboxylic esters from dialkyl 2-oxoglutarates
-
Enantiomerically pure tetrahydro-5-oxo-2-furancarboxylic esters can be prepared either by enzymatic resolution of the racemic γ-lactones themselves or by bioreduction with baker's yeast of dialkyl 2-oxoglutarates and subsequent cyclization of the resulting dialkyl 2-hydroxyglutarates. The best results were obtained by the former route, by which the desired compounds were isolated in high enantiomeric excess. Bioreductions were less satisfactory. In fact the hydroxyester intermediates were initially formed as racemic mixtures and their final enantiomeric enrichment was reached by asymmetric destruction, occurring in the bioreaction medium, however at the same time large amounts of alkyl 4-hydroxybutanoates were formed as side products.
- Drioli, Sara,Nitti, Patrizia,Pitacco, Giuliana,Tossut, Laura,Valentin, Ennio
-
p. 2713 - 2728
(2007/10/03)
-