Novel imidazopyridines and purines, medicaments containing these compounds, and processes for their preparation

The invention relates to novel imidazo derivatives of the formula in which A and B together with the two carbon atoms lying in between denote a pyridine or pyrimidine ring and R denotes a 5- or 6-membered heteroaromatic ring bonded via a carbon atom, which can contain an oxygen or sulphur atom, 1, 2 or 3 nitrogen atoms, an oxygen or sulphur atom and one or two nitrogen atoms, where an imino group which may be present can be substituted by an alkyl, alkanoyl, aminocarbonyl, alkylaminocarbonyl or dialkylamino group and an abovementioned heteroaromatic ring in the carbon ring system can simultaneously be substituted by one or two alkyl groups and an abovementioned pyridyl ring must additionally be mono- or disubstituted by halogen atoms, hydroxyl, alkoxy, alkylmercapto, amino, alkylamino, dialkylamino, piperidino, morpholino, piperazino or N-alkylpiperazino groups, their 1H-tautomers and their acid addition salts. The novel compounds and their physiologically tolerable acid addition salts have useful pharmacological properties, in particular an action on the blood pressure and on the contractility of the heart muscle and also antithrombotic actions, and can be prepared by processes known per se.