Abstract: The invention relates to oxadiazole derivatives which are histamine H-2 antagonists and which inhibit the secretion of gastric acid, to methods for their manufacture and to pharmaceutical compositions containing them. The oxadiazole derivatives are of the formula: ##STR1## in which Y is O, S, CH.sub.2 or a direct bond; m is 0 to 4 and n is 1 to 4, provided that when Y is S or O m is 1 to 4 and when Y is O n is 2 to 4; A is a 3,4-dioxocyclobuten-1,2-diyl radical or C=Z in which Z is O, S, NCN, NNO.sub.2, CHNO.sub.2, NCONH.sub.2, C(CN).sub.2, NCOR.sup.1, NCO.sub.2 R.sup.1, NSO.sub.2 R.sup.1 or NR.sup.2 in which R.sup.1 is alkyl or aryl and R.sup.2 is H or alkyl; B is alkoxy or alkylthio or NHR.sup.3 in which R.sup.3 is H or alkyl: and the salts thereof.

Abstract: The invention relates to guanidine derivatives of imidazoles and thiazoles which are histamine H-2 antagonists and which inhibit the secretion of gastric acid, to methods for their manufacture, to pharmaceutical compositions containing them and to methods of using such guanidine derivatives and compositions. The guanidine derivatives are of the general formula I: ##STR1## in which X is S or NH, Y is CH.sub.2, a direct bond or a vinylene radical, m is 0 to 4 and n is 1 to 4, R.sup.1 is hydrogen, halogen or alkyl, R.sup.2 is hydrogen, alkyl, alkanoyl or aroyl, A is a 3,4-dioxocyclobuten-1,2-diyl radical or C.dbd.Z in which Z is O, S, NCN, NNO.sub.2, CHNO.sub.2, NCONH.sub.2, C(CN).sub.2, NCOR.sup.3, NCO.sub.2 R.sup.3, NSO.sub.2 R.sup.3 or NR.sup.4 in which R.sup.3 is alkyl or aryl and R.sup.4 is hydrogen or alkyl, B is alkoxy or alkylthio or NR.sup.5 R.sup.6 in which R.sup.5 and R.sup.

Abstract: The invention relates to guanidine derivatives of imidazoles and thiazoles which are histamine H-2 antagonists and which inhibit the secretion of gastric acid, to methods for their manufacture, to pharmaceutical compositions containing them and to methods of using such guanidine derivatives and compositions. The guanidine derivatives are of the general formula I: ##STR1## in which X is S or NH, Y is O, S, or SO, m is 1 to 4 and n is suitably 1 to 4, R.sup.1 is hydrogen, halogen or alkyl, R.sup.2 is hydrogen, alkyl, alkanoyl or aroyl, A is a 3,4-dioxocyclobuten-1,2-diyl radical or C=Z in which Z is O, S, NCN, NNO.sub.2, CHNO.sub.2, NCONH.sub.2, C(CN).sub.2, NCOR.sup.3, NCO.sub.2 R.sup.3, NSO.sub.2 R.sup.3 or NR.sup.4 in which R.sup.3 is alkyl or aryl and R.sup.4 is hydrogen or alkyl, B is alkoxy or alkylthio or NR.sup.5 R.sup.6 in which R.sup.5 and R.sup.6 are independently hydrogen, alkyl, alkenyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, alkylaminoalkyl or dialkylaminoalkyl; and the salts thereof.

Abstract: The invention relates to guanidine derivatives of imidazoles and thiazoles which are histamine H-2 antagonists and which inhibit the secretion of gastric acid, to methods for their manufacture, to pharmaceutical compositions containing them and to methods of using such guanidine derivatives and compositions. The guanidine derivatives are of the general formula I: ##STR1## in which X is S or NH, Y is CH.sub.2, a direct bond or a vinylene radical, m is 0 to 4 and n is 1 to 4, R.sup.1 is hydrogen, halogen or alkyl, R.sup.2 is hydrogen, alkyl, alkanoyl or aroyl, A is a 3,4-dioxocyclobuten-1,2-diyl radical or C.dbd.Z in which Z is O, S, NCN, NNO.sub.2, CHNO.sub.2, NCONH.sub.2, C(CN).sub.2, NCOR.sup.3, NCO.sub.2 R.sup.3, NSO.sub.2 R.sup.3 or NR.sup.4 in which R.sup.3 is alkyl or aryl and R.sup.4 is hydrogen or alkyl, B is alkoxy or alkylthio or NR.sup.5 R.sup.6 in which R.sup.5 and R.sup.