Potential radioprotective agents. 2. Substituted anilines

A series of substituted anilines was examined for radioprotective activity by injecting them ip into mice subjected to a near-lethal dose of 6 mV photons. Electronegative groups such as Br, NO2, CN, and acyl in the meta or para position gave rise to highly active compounds (80-100% protection), while p-amino, methyl, amide, hydroxy, and fluoro groups decrease activity. No general correlations could be developed, however, between biological activity and a wide variety of calculated molecular parameters. The highest activity was found with p-aminobenzophenone (1), p-aminopropiophenone (2), its ethylene ketal (3), 2-amino-5-chloropyridine (35), and 5-amino-2-chloropyridine (36).