Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1980-10-14
1983-05-10
Schwartz, Richard A.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D23364
Patent
active
043831150
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a novel group of cyanoguanidine derivatives characterized by the following imino-alkyl and amino-nitrile structural formula: ##STR2## wherein R.sub.1 is a 2-mercapto-ethyl, a 2-hydroxy-ethyl, a 2-((4-methyl-5-imidazolyl)thio-methyl)ethyl, or a 2-((4-methyl-5-imidazolyl)dithioformyloxy-methyl)ethyl radical, and R.sub.2 represents a methyl radical.
A particularly advantageous compound of the invention: N-methyl-N'-cyano-N"-imino-[2-((4-methyl-5-imidazolyl)thio-methyl)ethyl]gu anidine is a histamine antagonist in the H.sub.2 receptors which inhibits the secretion of gastric acid, and can be used therapeutically for the treatment of gastric and duodenal ulcers.
This invention also relates to processes for the production of these novel cyanoguanidine derivatives.
BACKGROUND OF THE INVENTION
Cyanoguanidine derivatives synthesized by known processed are characterized by imino-nitrile guanidine structures having the following formula: ##STR3##
The stable conformations of the cyanoguanidines of formula II are represented by the following structures: ##STR4##
Structures IIa and IIb represent the anti(--NHR.sub.2) and syn(--NHR.sub.2) geometrical isomers of the formula II cyanoguanidines. These isomers do not demonstrate the phenomenon of tautomerism and thus, are not intermediates for the production of amino-nitrile and imino-alkyl cyanoguanidines having the following formula: ##STR5## In solution, the IIa and IIb isomers do not transform into each other. A high energy barrier prevents establishment of either a tautomeric or an E to Z isomeric equilibrium. This high energy barrier results from the rapidity of inversion of the --NCN group (probably by a rotational-bond mechanism) which is greater than the rate of rotation of the --NHR.sub.1 and --NHR.sub.2 groups.
SUMMARY OF THE INVENTION
This invention discloses a group of cyanoguanidine derivatives characterized by the following imino-alkyl and amino-nitrile formula: ##STR6## wherein R.sub.1 and R.sub.2 may or may not be identical. The invention also relates to a method for producing these novel cyanoguanidines.
Cyanoguanidines conforming to structure IV are unique, and their intermediate guanidines of structure I do not represent tautomers of either of the known formula II cyanoguanidines. The phenomenon of tautomerism involves the establishment of an equilibrium between the tautomers. If the formula I and II cyanoguanidines were in fact tautomers, upon dissolving the formula II cyanoguanidine in a suitable solvent, the corresponding formula I cyanoguanidine would also be found in the solution. It may be hypothesized that the absence of the formula I cyanoguanidine is due to an equilibrium situation in which the quantity of the formula I cyanoguanidine is reduced to a level at which its presence cannot be detected. If this were the case however, upon dissolving a formula I cyanoguanidine in the same solvent, it would be expected that it would be transformed into the corresponding formula II cyanoguanidine until it no longer existed in the solution above a trace amount. This does not occur, and it has been established that: corresponding formula I cyanoguanidine is not detected; corresponding formula II cyanoguanidine is not detected.
DETAILED DESCRIPTION OF THE INVENTION
Stable conformations which can be isolated from the formula I cyanoguanidines are the following: ##STR7##
The absence of a demonstrated tautomerism phenomenon between the formula Ia, Ib, Ic cyanoguanidines and the formula IIa or IIb cyanoguanidines is due to the respective molecular stability of each of these cyanoguanidine groups. The molecular stability of formula Ia and Ib cyanoguanidines is, most likely, caused by an interaction of the amino-nitrile component with the imino-alkyl component; within a planar structure. This interaction leads to a considerable decrease in the electrical moment of the nitrile component, as reflected by the disappearance of its infra-red absorption. The molecular stability of the formula Ia and Ib cyanoguanidines
REFERENCES:
patent: 4093621 (1978-06-01), Brown et al.
Smith, P., The Chemistry of Open-Chain Organic Nitrogen Compounds, vol. I, W. A. Benjamin, New York, 1965, pp. 178-179.
Shay, H. et al., Gastroenterology, 4(1), 43-61 (1945).
Balanzo, J. et al., Digestion, 13, 291-303 (1975).
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