Enzyme-Catalyzed Stereoselective Synthesis of Two Novel Carbasugar Derivatives

2010-01-01
Gumus, Aysegul
Tanyeli, Cihangir
Enzymatic resolution of racemic 1,4,5,6-tetrachloro-2-(hydroxymethyl)-7,7-dimethoxybicyclo[2.2.1]hept-5-ene (rac-1) using various lipases in vinyl acetate as acetyl source was studied. The obtained enantiomerically enriched (+)-(1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2.1]hept-5-en-2-yl)methyl acetate ((+)-2; 94% ee), upon treatment with Na in liquid NH3, followed by Amberlyst-15 resin in acetone, provided (-)-5-(hydroxymethyl)bicyclo[2.2.1]hept-2-en-7-one ((-)-7), which is a valuable precursor for the synthesis of carbasugar derivatives. Subsequent Baeyer-Villiger oxidation afforded a nonseparable mixture of bicyclic lactones, which was subjected to LiAlH4 reduction and then acetylation. The resultant compounds (-)-11 and (+)-12 were submitted to a cis-hydroxylation reaction, followed by acetylation, to afford the novel carbasugar derivatives (1S,2R,3S,4S,5S)-4,5-bis(acetoxymethyl)cyclo-hexane-1,2,3-triyl triacetate ((-)-(13)) and (1R,3R,4R,6R)-4,6-bis(acetoxymethyl)cyclohexane-1,2,3-triyl triacetate ((-)(14)), respectively, with pseudo-C-2-symmetric configuration. The absolute configuration of enantiomerically enriched unreacted alcohol (-)-1 (68% ee) was determined by X-ray single-crystal analysis by anchoring optically pure (R)-1-phenylethanamine. Based on the configurational correlation between (-)-1 and (+)-2, the absolute configuration of (+)-2 was determined as (1R,2R,4S).
HELVETICA CHIMICA ACTA

Suggestions

Synthesis of chiral acetoxy lactones via the Baeyer-Villiger oxidation of cyclic aromatic acetoxy ketones
Demir, Ayhan Sıtkı; Aybey, Asuman (Elsevier BV, 2008-12-01)
The alpha-acetoxylation of indanones and tetralones by using Mn(OAc)(3) followed by the enzyme catalyzed kinetic resolution of acetoxy ketones furnished both of the enantiomers of alpha-acetoxy ketones in good chemical and optical yields. The Baeyer-Villiger oxidation of alpha-acetoxy ketones with m-CPBA, CF(3)SO(3)H, and CH(2)O(2), at rt gives the corresponding lactones without racemization. The acetoxy ketone moiety migrates selectively in order to form lactones. The mild hydrolysis of lactones affords ph...
Synthesis and Laser Activity of Halo-Acridinedione Derivatives
Kaya, Muhammed Çağrı; Tuerker, Lemi (2009-03-01)
Synthesis of 10-(halophenyl)-9-(4-methoxyphenyl)-3,4,6,7,9,10-hexahydroacridine-1,8-(2H,5H)-dione derivates have been prepared and their absorption, emission, and laser properties have been evaluated. The structures of all the synthesized compounds were characterized by spectroscopic methods IR, H-1 NMR, C-13-APT, MS, and elemental analysis.
Evaluation of functional changes in akr overexpressing colorectal cell line sw480
Ermiş, Çağdaş; Banerjee, Sreeparna; Erel Göktepe, İrem; Department of Biochemistry (2021-2-02)
The Aldo-Keto Reductases (AKR) are nicotinamide adenine dinucleotide (NAD(P)H) dependent oxidoreductases that function in phase 1 metabolismbyreducingaldehydes and ketones into primary and secondary alcohols. Inthis protein superfamily, the expression of AKR1B1 and AKR1B10 enzymes have been linked by us and others to colorectal cancer (CRC). Over-activation of these enzymes in the presence of excess glucose can result in the activation of the polyol pathway, which causes oxidative stress and migh...
Response surface optimization of antidipteran delta-endotoxin production by Bacillus thuringiensis subsp israelensis HD 500
Tokcaer, Z; Bayraktar, E; Mehmetoglu, U; Özcengiz, Gülay; Alaeddinoglu, NG (Elsevier BV, 2006-02-01)
Response surface optimization of Bacillus thuringiensis subsp. israelensis HD 500 fermentation for the production of its toxin proteins Cry4Ba and Cry11Aa was performed. Since the interaction of the medium components as well as cultivation conditions were expected to influence the production of the toxin proteins, an experimental chart was prepared by accepting the previously reported optimal values for the most important parameters as zero points: [Mn], 10(-6) M; [K2HPO4], 50 mM; C:N ratio, 20:1 and incuba...
Synthesis and biological evaluation of optically active conjugated gamma- and delta-lactone derivatives
ŞARDAN, Melis; Sezer, Serdar; GUNEL, Aslihan; AKKAYA, MAHİNUR; Tanyeli, Cihangir (2012-09-15)
An efficient synthesis of racemic and both enantiomeric forms of heteroaryl substituted gamma- and delta-lactone derivatives derived from allyl and homoallyl alcohol backbones has been accomplished via ring closing metathesis reaction. 2-Heteroaryl substituted allyl and homoallyl alcohols have been efficiently resolved through enzymatic method with high ee (97-99%) and known stereochemistry. Antimicrobial and antioxidant activities of target lactones were evaluated.
Citation Formats
A. Gumus and C. Tanyeli, “Enzyme-Catalyzed Stereoselective Synthesis of Two Novel Carbasugar Derivatives,” HELVETICA CHIMICA ACTA, pp. 1882–1893, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55525.