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Enzymatic Acylation (enzymatic + acylation)
Selected AbstractsSynthesis, Protonation Behavior, Conformational Analysis, and Regioselective Enzymatic Acylation of the Novel Diamino Analogue of (E)-5-(2-Bromovinyl)-2,-deoxyuridine (BVDU).CHEMINFORM, Issue 7 2004Ivan Lavandera Abstract For Abstract see ChemInform Abstract in Full Text. [source] Improved Synthesis and Isolation of 2,- O -Methyladenosine: Effective and Scalable Enzymatic Separation of 2,/3,- O -Methyladenosine RegioisomersEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2009Saúl Martínez-Montero Abstract An efficient separation of a mixture of 2,/3,- O -methyladenosine regioisomers (1 + 2; 1:1) has been developed by selective enzymatic acylation using immobilized Pseudomonas cepacia lipase (PSL-C) in combination with acetonoxime levulinate as acyl donor. The 3,-hydroxy group of 2,- O -methyladenosine (1) was acylated with high selectivity (ca. 70,%), whereas an equal amount of 3,- O -methyladenosine (2) in the same solution resulted in minor acylation of 5,-hydroxy group (ca. 8,%). The differential behavior of both regioisomers towards enzymatic acylation allowed to develop a separation protocol. Upon extraction of the acylated products, the 3,- O -methyladenosine was isolated in 81,% yield and 97,% purity from the aqueous layer. Hydrolysis of acylated products in organic layer furnished 2,- O -methyladenosine in 67,% yield and 99,% purity. The separation process was successfully applied to the crude reaction mixture of methylated products (ca. 3:1 of 1/2) on 5-g scale. We also report on the use of methyl p -toluenesulfonate as a safe reagent for 2,- O -methylation of adenosine.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthesis of Water-Soluble Retinol Derivatives by Enzymatic MethodBIOTECHNOLOGY PROGRESS, Issue 3 2002Thierry Maugard Retinoids (vitamin A and derivatives) are of great commercial potential in cosmetics and pharmaceuticals such as skin care products. However, the clinical effectiveness of these retinoids is limited by skin irritation, water insolubility, and except for retinyl-esters, extreme instability. In this paper, an enzymatic method for preparing water-soluble retinol derivatives catalyzed by immobilized lipase is described. The synthesis is based on a unique strategy of two-step enzymatic acylation. Among the different synthesized compounds, the most water-soluble are the disaccharide derivatives such as saccharose retinyl adipate (nonionic water-soluble retinol derivative) and the sodium salt of retinyl diacids such as retinyl succinate sodium salt (ionic water-soluble retinol derivative). [source] Stereoselective Chemoenzymatic Preparation of ,-Amino Esters: Molecular Modelling Considerations in Lipase-Mediated Processes and Application to the Synthesis of (S)-DapoxetineADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010María Rodríguez-Mata Abstract A wide range of optically active 3-amino-3-arylpropanoic acid derivatives have been prepared by means of a stereoselective chemoenzymatic route. The key step is the kinetic resolution of the corresponding ,-amino esters. Although the enzymatic acylations of the amino group with ethyl methoxyacetate showed synthetically useful enantioselectivities, the hydrolyses of the ester group catalyzed by lipase from Pseudomonas cepacia have been identified as the optimal processes concerning both activity and enantioselectivity. The enantiopreference of this lipase in these reactions has been explained, at the molecular level, by using a fragment-based approach in which the most favoured binding site for a phenyl ring and the most stable conformation of the 3-aminopropanoate core nicely match the (S)-configuration of the major products. The conversion and enantioselectivity values of the enzymatic reactions have been compared in order to understand the influence of the different substitution patterns present in the phenyl ring. This chemoenzymatic route has been successfully applied to the preparation of a valuable intermediate in the synthesis of (S)-dapoxetine, which has been chemically synthesised in excellent optical purity. [source] | ||||||||||