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Markedly improving Novozym 435-mediated regioselective acylation of 1-β-d-arabinofuranosylcytosine by using co-solvent mixtures as the reaction media

Paper ID Volume ID Publish Year Pages File Format Full-Text
25717 43593 2006 9 PDF Available
Title
Markedly improving Novozym 435-mediated regioselective acylation of 1-β-d-arabinofuranosylcytosine by using co-solvent mixtures as the reaction media
Abstract

A comparative study was made of Novozym 435-catalyzed regioselective acylation of 1-β-d-arabinofuranosylcytosine with vinyl propionate for the preparation of the 5′-O-monoester in eleven co-solvent mixtures and three pure polar solvents. Novozym 435 displayed low or no acylation activity toward 1-β-d-arabinofuranosylcytosine in pure polar solvents, although those solvents can dissolve the nucleosides well. When a hexane–pyridine co-solvent system was adopted, both the initial rate and the substrate conversion were enhanced markedly. The polarity of co-solvent mixtures had significant effect on the reaction. Among the solvent mixtures investigated, the higher the polarity of the solvent mixture, the lower the initial reaction rate and the substrate conversion. It was also found that the acylation was dependent on the hydrophobic solvent content, the water activity and the reaction temperature. The most suitable co-solvent, initial water activity, and reaction temperature were hexane–pyridine (28:72, v/v), 0.07, and 50 °C, respectively. Under these conditions, the initial rate, the substrate conversion and the regioselectivity were as high as 91.1 mM h−1, >97% and >98%, respectively, after a reaction time of 6 h. Among the reaction mediums examined, the lowest apparent activation energy was achieved with hexane–pyridine (28:72, v/v), in which Novozym 435 also exhibited good thermal stability.

Keywords
1-β-d-Arabinofuranosylcytosine; Novozym 435; Acylation; Co-solvent
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Markedly improving Novozym 435-mediated regioselective acylation of 1-β-d-arabinofuranosylcytosine by using co-solvent mixtures as the reaction media
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 124, Issue 3, 25 July 2006, Pages 552–560
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us