Comparative nitrosation of etintidine and cimetidine
| Autor: | Thomas A. Montzka, John D. Matiskella, Ronnie R. Crenshaw, Henry M. Holava, Peter F. Juby |
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| Rok vydání: | 1983 |
| Předmět: | |
| Zdroj: | Canadian Journal of Chemistry. 61:1771-1777 |
| ISSN: | 1480-3291 0008-4042 |
| Popis: | 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 |
| Databáze: | OpenAIRE |
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