Fungi mediated enantioselective biohydrogenation of benzils to benzoins

Demirtaş, Umut
Benzoin is an important a-hydroxy ketone which can be used as chiral intermediate for the synthesis of several drugs. In this study, it was aimed to synthesize this compound by high stereoslectivity and yield by the use of fungal bioconversions. For this purpose, whole cells of four different Fusarium spp. (F. anguoides, F. roseum, F. solanii, F.bulbigenum) were used for reduction of readily available achiral compound benzil. The reaction conditions were optimized as glucose peptone broth consisting of 30g/L glucose and 10 g/L peptone, inoculum size as 20 mg/L and substrate concentration as 200 mg/L. A complete set of derivatives substituted with electron donating and electron withdrawing groups of the benzils were also reduced to the corresponding benzoin derivatives with the same optimized condition with up to 98% ee.


Fungi mediated conversion of benzil to benzoin and hydrobenzoin
Demir, AS; Hamamcı, Haluk; Ayhan, P; Duygu, AN; Igdir, AC; Capanoglu, D (2004-08-23)
An enzyme system of four fungi catalyses the reduction of benzil to benzoin, as well as benzoin to hydrobenzoin. Depending on the pH of the medium, both enantiomers of benzoin can be obtained in good yield and high ee starting from benzil via a reduction, as well as from rac-benzoin via a novel deracemization reaction. Starting from benzil, (R)-, (S)- and rac-benzoin only (R,R)-hydrobenzoin was obtained in high ee and chemical yield.
Fungal deracemization of benzoin
Demir, AS; Hamamcı, Haluk; Sesenoglu, O; Neslihanoglu, R; Asikoglu, B; Capanoglu, D (2002-09-02)
An enzyme system of Rhizopus oryzae (ATCC 9363) catalyzes the inversion of the chirality of benzoin via a deracemization reaction and, depending on the pH of the medium, both enantiomers of benzoin are obtained in good yield and high ee starting from rac-benzoin.
Investigation for natural extract inhibitors of bovine lens aldose reductase responsible for the formation of diabetis dependent cataract
Onay, Melih; Çoruh, Nursen; Department of Biochemistry (2008)
In the polyol pathway, Aldose reductase (AR) is an important enzyme in reduction of aldehydes and aldosugars to their suitable alcohols. AR, using NADPH as a coenzyme, has a molecular weight of 37 000 dalton. AR in its activated form, known to increase the sorbitol accumulation in lens, is responsible for the cataract formation in diabetis diseases. Therefore, the inhibition of aldose reductase is important to prevent the incedence of cataract formation in diabetus mellitus. In the treatment of diabetis dep...
Chemoenzymatic synthesis of chiral hydroxymethyl cycloalkenols
Şenocak, Deniz; Demir, Ayhan Sıtkı; Department of Chemistry (2004)
Chiral cyclic alkenols with hydroxymethyl functionality are important structural units in many biologically active natural compouds such as prostaglandins, sesquiterpene antiviral agents, pentenomycins, xanthocidin, sarkomycin, etc. 1,3-cycloalkanediones are converted into bicyclic polyoxo derivatives with formaldehyde and trioxane in the presence of Lewis acid. Selective oxidation of the bicyclic compounds by using manganese(III)acetate followed by enzyme-catalyzed kinetic resolution afforded chiral bicycl...
Synthesis of new mediators for electrochemical nad/nadh recycling
Khalily, Mohammad Aref; Demir, Ayhan Sıtkı; Department of Chemistry (2011)
The synthesis of enantiopure compounds can be achieved by using dehydrogenases as biocatalysts. For instance, reduction reactions of prochiral compounds (ketones, aldehydes and nitriles) into chiral compounds can be achieved by dehydrogenases. These dehydrogenases are cofactor dependent where cofactor is Nicotinamide Adenin Dinucleotite having some restrictions that confines usage of dehydrogenases in organic synthesis including instability of cofactor in water and high cost. Therefore, suitable recycling m...
Citation Formats
U. Demirtaş, “Fungi mediated enantioselective biohydrogenation of benzils to benzoins,” M.S. - Master of Science, Middle East Technical University, 2008.