Synthesis and H₂-antagonist properties of some 1,2,5-thiadiazole-1-oxide derivatives

A series of 1,2,5-thiadiazole-1-oxide derivatives has been synthesized and studied for its H₂-antagonist properties. These derivatives can be considered derived from classical H₂-antagonists in which the structure was deeply modified in order to evidence the minimal structural requirements for the activity. It was found that it is sufficient to have the 1,2,5-thiadiazole-1-oxide ring substituted with an alkylamino moiety and with an aliphatic chain linked to the hydroxy or ether group to achieve compounds as active as cimetidine. A few considerations on the binding on guinea-pig cerebral cortex of a series of H₂-antagonists with more and more simplified structures are also reported.