An Enzymatic Flow-Based Preparative Route to Vidarabine

Abstract

The bi-enzymatic synthesis of the antiviral drug vidarabine (arabinosyladenine, ara-A), catalyzed by uridine phosphorylase from <i>Clostridium perfringens</i> (<i>Cp</i>UP) and a purine nucleoside phosphorylase from <i>Aeromonas hydrophila</i> (<i>Ah</i>PNP), was re-designed under continuous-flow conditions. Glyoxyl-agarose and EziG^TM1 (Opal) were used as immobilization carriers for carrying out this preparative biotransformation. Upon setting-up reaction parameters (substrate concentration and molar ratio, temperature, pressure, residence time), 1 g of vidarabine was obtained in 55% isolated yield and >99% purity by simply running the flow reactor for 1 week and then collecting (by filtration) the nucleoside precipitated out of the exiting flow. Taking into account the substrate specificity of <i>Cp</i>UP and <i>Ah</i>PNP, the results obtained pave the way to the use of the <i>Cp</i>UP/<i>Ah</i>PNP-based bioreactor for the preparation of other purine nucleosides.