[Potential cardiotonic agents. 10. Synthesis and positive inotropic action of 5-(4-pyridinyl)- and 5-phenyl-substituted 2-alkylthio-3-cyan-pyridines and their S-oxidation products].

The alkylation of the 5-(4-pyridinyl)- and 5-phenyl-substituted 3-cyan-2(1H)-pyridinethiones 1 with alkyl iodides and halomethylcarbonyl compounds led to the 2-alkylthio-pyridines 3a-c, 3e, 3f and the thieno[2,3-b]pyridines 4, respectively. In an other way the 2-ethylthio-5-(4-pyridinyl)pyridines 3b and 3d were formed from the corresponding 2-chloroderivatives and ethylmercaptan. By means of oxidation of the 2-alkylthio-pyridines 3 with 3-chloroperbenzoic acid and potassium permanganate, respectively, the 2-sulfinyl- and 2-sulfonyl-pyridines 5 and 6 were obtained. The 3-cyano-5-(4-pyridinyl)pyridine-2-sulfonic acid 7 was prepared by oxidation of the 2(1H)-pyridinethione 1a with potassium permanganate. Some derivatives possess positive inotropic properties.