Acrylamides, enantioselective acids

In basic chemicals, nitrile hydratase and nitrilases have been most successful. Acrylamide from acrylonitrile is now a 30 000 tpy process. In a product tree starting from the addition of HCN to butadiene, nicotinamide (from 3-cyanopyridine, for animal feed), 5-cyanovaleramide (from adiponitrile, for herbicide precursor), and 4-cyanopentanoic acid (from 2-methylglutaronitrile, for l,5-dimethyl-2-piperidone solvent) have been developed. Both the enantioselective addition of HCN to aldehydes with oxynitrilase and the dihydroxylation of substituted benzenes with toluene (or naphthalene) dioxygenase, which are far superior to chemical routes, open up pathways to amino and hydroxy acids, amino alcohols, and diamines in the first case and alkaloids, prostaglandins, and carbohydrate derivatives in the second case. 

C. Enantioselective photocyclization of acrylamides catalyzed by chiral acids... 

Besides a highly active nitrile hydratase employed in the industrial production of acrylamide and nicotinamide [7-10] and a nitrilase [14,20-22], R. rhodochrous J1 contains an amidase with a high (5)-specificity in the hydrolysis of 2-phenylpropionamide. The corresponding gene was cloned and overexpressed in E. coli [71,72]. The recombinant enzyme was used for the preparation of (5)-2-phenylpropionic acid with high enantiomeric purity (Fig. 24) but could not recognize the configuration of 2-chloropropionitrile presumably due to the requirement of a bulky moiety for enantioselectivity. 

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