Modifications of primiaquine as antimalarials. 2. 5-Phenylthio and 5-anilino derivatives of primaquine.

A number of 5-phenylthio and 5-anilino derivatives of primaquine have been prepared which are less toxic but less active than primaquine itself in murine and monkey antimalarial screens. It is apparent that the toxicity of primaquine can be diminished by introduction at position 5 of phenylthio, anilino, or phenoxy groups. However, the best hope for concomitant retention of high activity would seem to reside with the phenoxy moieties.