The IIBr cleavage of hubstit iited 2-uxazolidinoncs was effectively: ipplied ill the byntlicsis of h'-substituted and N, S-disubstituted derivatives of 2-aminoethanethiol in which the?; substituent is a 2-phenoxy-,(phenylthio)-,(phenylsulfonyl)-, or (2-pyridy1thio) ethyl or a correspondingly 3-substituted propyl group. h'one of these modifications of the amino group led to radioprotective activity approaching that of the parent compounds. Bmong the thiols, ...