3-Alkylxanthines, processes for their preparation and compositions for use in the treatment of chronic obstructive airway disease and cardiac disease.

3-Alkylxanthines characterized by the formula …<CHEM>… wherein R<1> is n-propyl, n-butyl, isobutyl, n-pentyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, cyclopropyl, cyclobuty, cyclopentyl of cyclohexylmethyl, and R<2> is hydrogen or methyl, provided that R<2> is methyl when R<1> is n-propyl, n-butyl or isobutyl, or a physiologically acceptable salt thereof, for example the compound 3-cyclopetnyl-3, 7-dihydro-1H-purine-2, 6-dione, have activity against chronic obstructive airway disease or cardiac disease. These compounds are produced by several methods, exemplified by the following one: reacting a compound of the formula …<CHEM>… with a compound of the formula… R<2>-X… wherein R<1> and R<2> have the definition given above and X is -COOH, -CONH2 or -OC-O-CO-R2 and, if necessary, submitting the obtained product to dehydration. The starting compounds wherein R<1> is n-pentyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, cyclopropyl, cyclobutyl, cyclopentyl or cylohexylmethyl are not previously described in teh literature They are prepared by reacting a compound of the formula R<1>NHCONH2 with cyanoacetic acid, cyclising the produced 1-cyanoycetyl-3-R<1>urea with alkali, nitrosing the so produced 1-R<1>-6-aminouracil with HNO2 and reducing the so produced 1-R<1>-5-nitroso-6-aminouracil with H2//PtO2.