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-methoxybenzyl)-4-py rimidone and 2-[2-(5-methyl-4-imidazolylmethylthio)ethylamino]-5-benzyloxy-4-pyrimidone .
这些化合物是取代的异
胞嘧啶,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-
咪唑甲基
硫基)乙基
氨基]-5-(3-
甲氧基苯基)-4-
吡咯酮和2-[2-(5-甲基-4-
咪唑甲基
硫基)乙基
氨基]-5-苄氧基-4-
吡咯酮。