Compounds of the formula: ##STR1## wherein R.sup.1 is hydrogen, cyano or cyano(lower)alkyl; R.sup.2 is hydrogen, cyano, carboxy, carbamoyl, guanyl, (lower)alkoxyimino, hydrazinocarbonyl, (lower)alkylaminoimino, ##STR2## with the proviso that one but never both of R.sup.1 and R.sup.2 is hydrogen; and the pharmacologically acceptable salts thereof exhibit H.sub.2 -receptor antagonist and gastric secretion inhibition activity.
该化合物的结构式为:##STR1## 其中R.sup.1是氢、
氰或
氰(较低)烷基;R.sup.2是氢、
氰、羧基、
氨基甲酰基、
鸟氨酸基、(较低)烷氧基
亚胺基、
肼基甲酰基、(较低)烷基
氨基
亚胺基,##STR2##但是R.sup.1和R.sup.2中只有一个是氢,从而产生药理学上可接受的H.sub.2-受体拮抗剂和抑制胃分泌活性的盐。