Synthesis Of Dinitriles For Nitrilase's Substrates And Enantioselective Hydrolysis Of 2-arylpropionic Acid

A bacterium Rhodococcus ruber 4.1187 was chosen as the catalyst among several strains in the laboratory due to its high enantioselectivity and activity for the conversion of (DL) (DL)-2-methylbenzyl cyanide to (S)-2-Phenylpropionic acid. The two enzymes of Nitrile Hydratase and Amidase werw found in it. The Nitrile Hydratase showed high activity with little enantioselectivity. On the contrary, the activity of Amidase is relative low, but the enantioelectivity was extraordinary high. Therefore, the reaction conditions by the resting cells of Rhodococcus ruber 4.1187 were optimized when (DL)-2-phenylpropanamidewas employed as the substrate, giving the optimal conditions ad follows:pH 7.5 (Tris-HCl,100 mM,30℃, DMSO as the cosolvent, and 100 mM substrate concentration. Finally,10 gram resting cells of Rhodococcus ruber 4.1187 as catalyst was used for the reaction at gram scale. As a result, (S)-(+)-2-Phenylpropionic acid was obtained in the yield of 46% with 99% e.e.; and (R)-(-)-2-phenylpropanamide was also isolated with a moderate yield of 47% and e.e.of 95.7%.(the e.e. up to 99% after recrystallisation).In this dissertation, twelve disubstitute-malononitrile substrates were synthesized through two-step and one-pot-two-step. Also, Rhodococcus ruber 4.1187 displayed activities toward the twelve substrates, while no obvious activity was observed for the Nitrilase producing strain Alcaligenes sp. ECU0401.