N,N''-(dithio-2,1-ethanediyl)bis[N'-(pyrrol-2-ylmethyl)-1, 6,- hexanediamine] (pyrextramine), a new irreversible alpha 1-adrenoreceptor blocking agent of the tetramine disulfide class.

In an attempt to further improve the alpha-adrenoreceptor blocking activity of benextramine, the effect of heteroaromatic substituents on the terminal nitrogens was studied. In this communication we report on the newly synthetized N,N''-(dithio-2,1-ethanediyl)bis[N'-(pyrrol-2-ylmethyl)-1,6- hexanediamine] (pyrextramine) that displayed higher affinity (5-10-fold) and higher selectivity (about 12-fold) than benextramine. These preliminary results show that pyrextramine can replace benextramine in the elucidation and characterization of the peripheral alpha 1-adrenoreceptors.