Synthesis and Properties of 4,6-Dimethyl-5-pentyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile and 3-Amino-4,6-dimethyl-5-pentylthieno[2,3-b]pyridines

The reaction of 3-pentylpentane-2,4-dione with cyanothioacetamide afforded 4,6-dimethyl-5-pentyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile. Alkylation of the latter led to the formation of 2-alkylsulfanyl-4,6-dimethyl-5-pentylpyridine-3-carbonitriles or 3-amino-4,6-dimethyl-5-pentylthieno[2,3-b]pyridines, depending on the alkylating agent and reaction conditions. The structures of the key compounds were proved by 2D NMR spectroscopy and X-ray analysis. Biological activity of the synthesized compounds was evaluated in silico. Some compounds were experimentally found to stimulate growth of sunflower seedlings.