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- Title
Highly regioselective enzymatic synthesis of 5′- O-stearate of 1- β-D-arabinofuranosylcytosine in binary organic solvent mixtures.
- Authors
Li, Xiao-feng; Zong, Min-hua; Zhao, Guang-lei
- Abstract
In this paper, highly regioselective enzymatic acylations of 1- β-D-arabinofuranosylcytosine (ara-C) with vinyl stearate (VS) in binary organic solvents were explored for the preparation of 5′- O-stearate of ara-C with potential antitumor activity. Twelve kinds of hydrolases were tested for the regioselective acylation reaction and the immobilized Candida antarctica lipase B (Novozym 435) showed the highest regioselectivity (>99.9%) towards the 5′-OH of ara-C. A comparative study showed that the lipase had much higher catalytic activity in the binary mixture of hexane and pyridine than in other tested co-solvent systems. To better understand lipase-mediated acylation conducted in the best binary organic solvent system, the effects of hydrophobic solvent content, molar ratio of VS to ara-C, initial water activity, and reaction temperature on the acylation reaction were studied. It was found that the most suitable hexane content, VS–ara-C molar ratio, initial water activity, and reaction temperature were shown to be 25% ( v/ v), 20:1, 0.07, and 50°C, respectively. Under these reaction conditions, the initial reaction rate, the maximum substrate conversion, and regioselectivity were as high as 86.0 mmol·L−1h−1, 96.6%, and >99.9%, respectively. The product of Novozym 435-catalyzed acylation was characterized by Carbon-13(13C) NMR and confirmed to be 5′- O-stearate of ara-C.
- Subjects
ENZYMES; CHEMICAL synthesis; ORGANIC solvents; ACYLATION; ANTINEOPLASTIC agents; STEARATES; LIPASES; HEXANE; PYRIDINE spectra; SUBSTRATES (Materials science)
- Publication
Applied Microbiology & Biotechnology, 2010, Vol 88, Issue 1, p57
- ISSN
0175-7598
- Publication type
Article
- DOI
10.1007/s00253-010-2705-1