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US 4,049,671 AGranted
Process for preparing N-cyanoguanidines
AssigneeSmith Kline & French Laboratories Limited
InventorsGraham John Durant, Charon Robin Ganellin, George Raymond White
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Abstract
Process for preparing N-cyanoguanidines by treating N-(loweralkyl)-N'-cyano-isothioureas with an amine and a heavy metal salt. A specific product is N-cyano-N'-methyl-N"-[2-((5-methyl-4-imidazolyl)methylthio)ethyl]guanidine , useful as a histamine H.sub.2 -antagonist.
Claims8
In a process for the preparatin of a cyanoguanidine of the formula:
- ##STR4## wherein R.sub.1 is lower alkyl and R.sub.2 is a grouping of structure Het-(CH.sub.2).sub.m Z(CH.sub.2).sub.n -- wherein Het is an imidazole, pyridine, thiazole, isothiazole, oxazole, isoxazole, triazole or thiadiazole ring, which ring is optionally substituted by lower alkyl, hydroxyl, halogen or amino;
- Z is sulphur, oxygen or a methylene group;
- and m is 0, 1 or 2 and n is 2 or 3, such that the sum of m and n is from 2 to 4;
- in which an isothiourea of the formula:
- ##STR5## wherein R.sub.1 and A, which may be the same or different, are lower alkyl, is treated with an amine of formula R.sub.2 NH.sub.2 wherein R.sub.2 has the same significance as hereinabove, the improvement wherein the reaction is carried out using a suitable heavy metal salt.
2 more elements
Dependencies are inferred from the claim text.