Steric structure–activity relationships of the rice blasticide,S-2900 (diclocymet)

The four diastereomers of 2-cyano-N-[1-(2,4-dichlorophenyl)ethyl]-3,3-dimethyl-butyramide were prepared by a direct HPLC separation with chiral columns. The [(S)acid, (R)amine]-isomer (was the most antifungal among the diastereomers tested. Because of the lability of the clinical group in the acid moiety, the (RS)-(R)-isomer is being developed as a rice blasticide. (S-2900, proposed common name diclocymet).