disclosed are 2 , 3 - diamino - 1 , 4 - butanedithiol ; 4 , 5 - diamino - 1 , 2 - dithiane ; and their n - acyl and n - alkyl derivatives . also disclosed are processes for preparing the disclosed compounds ; pharmaceutical compositions comprising such compounds ; and a method of treatment comprising administering such compounds and compositions when an antihypertensive effect or radioprotective effect is indicated .