The compounds are substituted isocytosines which are histamine H.sub.2 -antagonists. Two specific compounds of the present invention are 2-[2-(5-methyl-4-imidazolylmethylthio)ethylamino]-5-(3-pyridylmethyl)-4-py rimidone and 2-[2-(3-bromo-2-pyridylmethylthio)-ethylamino]-5-(4-pyridylmethyl)-4-pyrim idone.
这些化合物是取代的异
胞嘧啶,它们是
组胺H.sub.2-拮抗剂。本发明的两种特定化合物是2-[2-(5-甲基-4-
咪唑基甲
硫基)乙基
氨基]-5-(3-
吡啶甲基)-4-
吡咯酮和2-[2-(3-溴-2-
吡啶甲
硫基)-乙基
氨基]-5-(4-
吡啶甲基)-4-
吡咯酮。