The cyano-NNO-azoxy function in the design of an irreversible label for alpha 1 adrenoreceptors

A potential alpha 1-adrenergic irreversible antagonist 6, containing the cyano-NNO-azoxy function was synthesized and tested. The effects of norepinephrine on rat thoracic aorta were irreversibly blocked by this compound at the concentration of 1 x 10(-5) M after 60 minutes. Binding studies showed that 6, at 1 x 10(-6) M, did not modify the KD of Prazosin and caused a 30% decrease of the Bmax. Substitution in 6 of the bis (2-chloroethyl)amino moiety for the cyano-NNO-azoxy function afforded 7 which behaves as an irreversible antagonist able to change KD of Prazosin without influencing Bmax.