title: Enantioselective Synthesis of Various Cyanohydrins Using Covalently Immobilized Preparations of Hydroxynitrile Lyase from Prunus dulcis.
abstract: The carrier-based and carrier-free (cross-linked enzyme aggregate) covalent immobilizations of Prunus dulcis hydroxynitrile lyase were investigated. The immobilized preparations were tested for enantioselective carbon-carbon bond formation activity in the biphasic medium. Of the tested preparations, only cross-linked enzyme aggregate of P. dulcis hydroxynitrile lyase (PdHNL-CLEA) achieved the synthesis of (R)-mandelonitrile with 93% yield and 99% enantiopurity. PdHNL-CLEA was also used in the synthesis of various (R)-cyanohydrins from corresponding aldehydes/ketones and hydrocyanic acid. When 4-methoxybenzaldehyde, 4-methyl benzaldehyde, and 4-hydroxybenzaldehyde were used as substrates, the yield-enantiomeric excess of corresponding (R)-cyanohydrins were obtained as 95-95, 85-79, and 2-25%, respectively, after 96 h at pH 4.0 and 5 °C. For acetophenone, 4-fluoroacetophenone, 4-chloroacetophenone, 4-bromoacetophenone, and 4-iodoacetophenone, the yield-enantiomeric excess of corresponding (R)-cyanohydrins were 1-99, 20-84, 11-95, 5-99, and 3-24%, respectively at the same conditions. The results demonstrate PdHNL-CLEA can be effectively used in the synthesis of (R)-mandelonitrile.
authors: Vocational School of Imamoglu, University of Cukurova, Adana, Turkey. dalagoz@cu.edu.tr.
authors: Dilek
authors: D
authors: Alagöz
authors: Department of Chemistry, Faculty of Science and Letters, University of Cukurova, 01330, Adana, Turkey.
authors: S Seyhan
authors: SS
authors: Tükel
authors: Vocational School of Ceyhan, University of Cukurova, Adana, Turkey.
authors: Deniz
authors: D
authors: Yildirim
mesh_terms: D000097:Acetonitriles / Q000138:chemical synthesis* / Q000737:chemistry; D000446:Aldehyde-Lyases / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D000068181:Prunus dulcis / Q000201:enzymology*; D013237:Stereoisomerism
chemical_list: D000097:Acetonitriles; D004800:Enzymes, Immobilized; D010940:Plant Proteins; C045516:mandelonitrile; D000446:Aldehyde-Lyases; C021541:mandelonitrile lyase
keywords: Aromatic aldehydes and ketones; CLEA; Enantiopure cyanohydrin; Prunus dulcis hydroxynitrile lyase