2-Pyridinemethanethiol 1, which is structurally related to cysteamine, showed good radioprotective potency in mice, but 2-pyrazine-methanethiol 9 was inactive. Certain derivatives of 1 and 9 that were synthesised were radioprotective. The 3 isomeric mercaptopyridines showed activity. Further study of N-heteroaromatic compounds as radioprotectors is indicated. An improved method for the preparation of 9 is described
