1,2,5-thiadiazol-3,4-diamine derivatives as histamine h.sub.2-receptor antagonists

Abstract From the Canadian patent

Compounds of the formula (I) :- (I), or pharmaceutically acceptable salts are described wherein, R1 and R2 are independently hydrogen or C1-6alkyl or R1, and R2 together represent - (CH2)q- wherein q is 4 to 7 to, form together with the nitrogen atom to which they are attached, a 5-8 membered saturated ring optionally, substituted by C1-6alkyl; X is -CH2- or sulphur; n is 2 or 3, or if X is -CH2- n can also be 1; p is 1 or 2; and R3 is hydrogen, C1-6alkyl, C3-6alkenyl or C3-6alkynyl (wherein the unsaturated bond is not adjacent to the -NHmoiety). The compounds are histamine H2-receptor antagonists and are useful in treating diseases mediated via histamine H2-receptors. Processes for their …