Synthesis of ( R)-2-trimethylsilyl-2-hydroxyl-ethylcyanide catalyzed with ( R)-oxynitrilase from loquat seed meal Article Received: 28 July 2004 Accepted: 15 November 2004 Abstract
The synthesis of optically active (
R)-2-trimethylsilyl-2-hydroxyl-ethylcyanide by asymmetric trans-cyanation of acetyltrimethylsilane with acetone cyanohydrin in a biphasic system was achieved using ( R)-oxynitrilase from loquat seed meal. Diisopropyl ether was the most suitable organic phase among the organic solvents examined. The optimal concentration of acetyltrimethylsilane, concentration of crude enzyme, volume ratio of the aqueous to the organic phase, temperature and the buffer pH value were 14 m M, 61.4 U ml -1, 13% (v/v), 30 °C and 4, respectively. The substrate conversion and the product enantiomeric excess were 95% and 98% under the optimized conditions. Acetyltrimethylsilane was a better substrate of the enzyme than its carbon counterpart.
Keywords cyanohydrin organosilicon compound ( R)-oxynitrilase transcyanation ( R)-2-trimethylsilyl- 2-hydroxyl-ethylcyanide
Revisions requested 24 August 2004; Revisions received 12 November 2004
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