Industrial Biotransformations

Lipase
Candida antarctica
● The product is easily separated. On treating the 1:1 aqueous solution of (S)-acid (main product)
and (R)-ester with a dichloromethane solution of CBZ chloride with the pH maintained at 7.0,
the (R)-ester partitions into organic solvent as the carbamate, whilst the required (S)-acid
remains unreacted in the aqueous phase. The desired product is then isolated simply by concentration
and cooling.
● The (R)-ester can be recovered in quantitative yield from the dichloromethane layer, racemized
and deprotected to regenerate racemic methyl ester to be recycled back into the resolution process.
● In contrast the chemical synthesis was derived using (S)-aspartic acid. The reaction was lowyielding
(~40 %). The chiral purity of product fell to ~96 %. This translated into drug substance
of an unacceptable ee of 91 %.
● A biocatalytic resolution seems an ideal solution.
3) Flow scheme
Not published.
4) Process parameters
conversion: 90 %
yield: 84 % (overall 42 %)
selectivity: 100 %
optical purity 99 %
chemical purity: 99 %
reactor type: batch
reactor volume: 2400 L
capacity: several hundred kilograms of product
down stream processing: extraction, distillation, cooling, centrifugation, drying in vacuum
enzyme consumption: few kg per hundred kg product (at least 100 reuses of the resin
possible)
enzyme supplier: Roche Diagnostics, Switzerland
production site: GlaxoSmithKline plc, U.K.
company: GlaxoSmithKline Pharmaceuticals, U.K.
5) Product application
● Lotrafiban is an orally active GPIIb/IIIa fibrinogen receptor antagonist designed for the prevention
of thrombotic events.
6) Literature
EC 3.1.1.3
● Walsgrove, T.C., Powell, L., Wells, A. (2002) A practical and robust process to produce
SB-2124857, Lotrafiban, [(2S)-7-(4,4′-bipiperidinylcarbonyl)-2,3,4,5,-tetrahydro-4-methyl-4-oxo-
1H-1,4-benzodiazepine-2-acetic acid] utilising an enzymatic resolution as the final step, Org.
Proc. Res. Dev. 6, 488–491
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