中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
2-(((5-甲基-1H-咪唑-4-基)甲基)硫代)乙胺 | 4-methyl-5-<(2-aminoethyl)-thiomethyl>-imidazole | 38585-67-0 | C7H13N3S | 171.266 |
N-氰基-N-[2-(5-甲基咪唑-4-甲硫)乙基]-S-甲基异硫脲 | N-Cyano-N'-<2-<(5-methyl-4-imidazolyl)-methylthio>-ethyl>-S-methyl-isothioharnstoff | 52378-40-2 | C10H15N5S2 | 269.395 |
Etintidine (4), a new histamine H2-receptor antagonist, was compared with cimetidine (1) for susceptibility to in vitro nitrosation at pH 1 and pH 3. Each agent formed two mono-N-nitrosoguanidine derivatives: N-cyano-N′-2-[(5-methyl-1H-imidazol-4-yl)methylthio]ethyl}-N″-nitroso-N″-(2-propynyl)guanidine (5) and N-cyano-N′-2-[5-methyl-1H-imidazol-4-yl)methylthio]ethyl}- N′-nitroso-N″-(2-propynyl)guanidine (6) from etintidine and N-cyano-N′-methyl-N″-2-[(5-methyl-1H-imidazol-4-yl)methylthio]ethyl}- N′-nitrosoguanidinc (2) and N-cyano-N′-methyl-N"-2-[(5-methyl-1H-imidazol-4-yl)methyl-thio]ethyl}-N′-nitrosoguanidine (11) from cimetidine. The N-nitroso derivative 5 from etintidine cyclized to 2-cyanoimino-3-2-((5-methyl-1H-imidazol-4-yl)methylthio]ethyl}-N″-methylene-1-nitroso-imidazoline (7) at neutral or basic pH's. Both agents were nitrosated less at pH 3 than at pH 1, and at both pH's nitrosation of etintidine was considerably less than that of cimetidine. At pH 1, with a nitrite concentration about 150–500 times that expected in fasting human gastric juice, formation of 5 and 6 from etintidine was barely detectable (each < 0.5%). Comments are made on the standard WHO conditions for investigating nitrosation of drugs.