The synthesis and irreversible a-blocking activity in the rat vas deferens of a series of tetra- and diamine disulfides 2-38, structural analogues of benextramine (BHC), are described. All compounds containing a central cystamine moiety displayed an irreversible a-adrenergic blockade at concentrations ranging from to 6 X lo4 M. Potency was increased in cystamines N, N'-disubstituted with 6-aminohexyl groups, especially when the outer nitrogen atoms ...