The study of structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen: II. Derivatives of m-fluoro-DL-phenylalanine.

The fluoro-, chloro-, methoxy- and nitro-substituted benzoyl derivatives of m-fluoro-DL-phenylalanine, substituted singly at the ortho, meta or para position of the benzoyl phenyl ring, were prepared and tested for growth-inhibitory activity in a Lactobacillus casei system used as an antitumor prescreen. The substituted benzoyl derivatives that were previously found to be the most active for o-fluoro-DL-phenylalanine were also the most active for the m-fluoro-DL-phenylalanine. The position of the fluorine substituent in the phenylalanine also appeared to be important for inhibitory activity as the derivatives of m-fluoro-phenylalanine were in general better inhibitors than those of the corresponding o-fluorophenylalanine.