Chemoenzymatic synthesis of biologically active natural products

Turkut, Engin
Racemic metyhl 3-cyclohexene-1-carboxylate was resolved via enzymatic hydrolysis to afford the enantiomerically enriched 3-cyclohexene-1-carboxylic acid with PLE (S-configuration), HLE (S-configuration), CCL (S-configuration) and PPL (R-configuration) . The nucleoside?s precursor, 5-(hydroxymethyl)-2-cyclohexen-1-ol (19), was synthesized by iodolactonization, followed by iodine elimination and the reduction of the lactone. In connection with this work, alpha,beta-unsaturated and saturated cyclic ketones were selectively oxidized on alpha'- and alpha-positions using Mn(OAc)3 and Pb(OAc)4, respectively. The resultant racemic alpha'- and alpha-acetoxylated substrates were resolved into corresponding enantiomerically enriched alpha'- and alpha-hydroxylated and acetoxylated compounds via PLE hydrolysis.


Chemoenzymatic synthesis of enantiomerically enriched 2-oxobicyclo[m.1.0]alkan-3-yl acetate derivatives
ÖZDEMİRHAN, FAZİLET DEVRİM; ÇELİK, MURAT; ATLI, SELİN; Tanyeli, Cihangir (Elsevier BV, 2006-01-23)
Racemic alpha'-acetoxy alpha,beta-unsaturated cyclopentanone and cyclohexanone have been resolved into the corresponding enantiomerically enriched alpha'-hydroxylated and acetoxylated compounds with 96-97% ee via PLE hydrolysis. Stereoselectivity in the palladium(II)-catalyzed reaction between the enantiomerically enriched alpha'-acetoxylated compounds and diazomethane has been investigated. In the alpha'-acetoxylated cyclopentenone, preferential cyclopropanation occurs in the anti-form, whereas alpha'-acet...
Chemoenzymatic Conversion of Linoleic Acid into Conjugated Linoleic Acid
Demir, Ayhan Sıtkı; Talpur, Farah N. (American Chemical Society (ACS), 2010-02-10)
An efficient chemoenzymatic method for preparing conjugated linoleic acid (CLA) using free linoleic acid (LA) as a substrate is described. In the first step, LA was transformed into 10-hydroxy-cis-12-octadecenoic acid (HA) by the whole cells of Lactobacillus plantarum after 48 h of incubation. The preincubation of whole cells with 0.03% LA resulted in a better yield of HA (480 mg/g) compared to cells grown without LA. In a second fast microwave step, HA was converted to cis-9, trans-11-octadecadienoic acid ...
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, characterization and electrochromic properties of conducting copolymers of 3-[(3-thienylcarbonyl)oxy]-2,2-bis{[(3-thienylcarbonyl)oxy]}propyl 3-thiophene carboxylate with thiophene and pyrrole
Bulut, U; Yilmaz, F; Yagci, Y; Toppare, Levent Kamil (Elsevier BV, 2004-01-01)
3-[(3-Thienylcarbonyl)oxy]-2,2-bis{[(3-thienylcarbonyl)oxy]}propyl 3-thiophene carboxylate (TOTPT) was synthesized by the reaction of 3-thionylcarbonyl chloride with pentaerythritol, it was electrochemically polymerized with either thiophene or pyrrole by using tetrabutylammonium tetrafluoroborate (TBAFB) as the supporting electrolyte in acetonitrile (AN). Characterization of the resulting copolymers was carried out by FTIR spectroscopy, cyclic voltammetry, thermal gravimetry analysis (TGA), differential sc...
Chemoenzymatic synthesis of both enantiomers of 3-hydroxy-2,3-dihydro-4H-chromen-4-one
Demir, AS; Aybey, A; Sesenoglu, O; Polat, Faruk (Elsevier BV, 2003-06-06)
4-Oxo-3,4-dihydro-2-chromen-3-yl acetate is synthesized using manganese(III)acetate starting from 2,3-dihydro-4H-chromen-4-one. K2CO3 mediated hydrolysis of 4-oxo-3,4-dihdro-2-chromen-3-yl acetate furnished 3-hydroxy-2,3-dihydro-4H-chromen-4-one in high yield. The enantioselective hydrolysis of (+/-)-4-oxo-3,4-dihydro-2-chromen-3-yI acetate in various organic solvent-phosphate buffer (pH7) systems and enantioselective transesterification of (+/-)-3-hydroxy-2,3-dihydro-4H-chromen-4-one in organic solvents wa...
Citation Formats
E. Turkut, “Chemoenzymatic synthesis of biologically active natural products,” M.S. - Master of Science, Middle East Technical University, 2004.