A new manufacturing process for (S)-3-(aminomethyl)-5-methylhexanoic acid (Pregabalin), the active ingredient in Lyrica, has been developed. Using Lipolase, a commercially available lipase, rac-2-carboxyethyl-3-cyano-5-methylhexanoic acid ethyl ester (1) can be resolved to form 2-carboxyethyl-3-cyano-5-methylhexanoic acid (2). A heat-promoted decarboxylation of 2 efficiently generates (S)-3-cyano-5-methylhexanoic acid ethyl ester (3), a known precursor of Pregabalin. This new route dramatically improved process efficiency compared to the first-generation process by setting the stereocenter early in the synthesis and enabling the facile racemization and reuse of (R)-1. The chemoenzymatic process also reduced organic solvent usage resulting in a mostly aqueous process. Compared to the first-generation manufacturing process, the new process resulted in higher yields of pregabalin (40-45% after one recycle of (R)-1), and substantial reductions of waste streams corresponding to a 5-fold decrease in the E factor from 86 to 17.

In a pharmaceutical environment, the need for efficient and practical screening techniques has become vital in the search for ideal enzymes that can be used in the preparation of drug intermediates. This paper describes a general high throughput screening (HTS) protocol that has been validated by a number of global projects within Pfizer. It outlines the procedures for the preparation of screening kits, as well as protocols for reaction set-up, optimization and analysis. The need for such protocols in routinely evaluating the use of solvent engineering in enzymatic hydrolysis reactions is also outlined, with several examples provided. The advantages and disadvantages of a number of complementary analytical tools that are being used in the analysis of enzymatic reactions are also discussed.

[structure: see text] A chemoenzymatic synthesis was described to prepare proposed oxidation-cyclization-methylation intermediates of the coumarin antibiotic biosynthetic pathway. The successful synthesis of these fragile molecules relies heavily on mild enzymatic deprotection and efficient enzymatic kinetic resolution to minimize epimerization, decomposition, multiple orthogonal protections, and retro aldol reactions often encountered in their chemical synthesis.

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