One-pot Synthesis of new 4,5,6,7-tetrahydro-3H-[1,2]dithiolo[3,4-b]pyridines starting from N,N’-Diphenyldithiomalondiamide

Active methylene compounds such as thioamides are widely used in the organic chemistry for construction of a variety of heterocyclic systems such as thieno[2,3-b]pyridines, 1,2,4-dithiazoles, isothiazoles, 1,2,3-thiadiazoles etc. N,N’-Diphenyldithiomalondiamide (dithiomalondianilide) as compound with methylene active group also is of interest as starting reagent for the synthesis of new N,S-containing heterocycles with potential pharmacological application. However, the reactions of dithiomalondianilide are poorly studied. Thus, up to date only a few reactions with dithiomalondianilide were reported to give heterocyclic compounds. Recentle we have reported a new reaction of dithiomalondianilide with 2-cyanoacrylates resulted in the formation of new dithiolopyridines. We suggested that the reaction is applicable to a wide range of Michael acceptors. In the present study we report the first example of the synthesis of dithiolopyridine-5-carboxamides through the reaction of dithiomalondianilide with 3-aryl-2-cyanoacrylamides. The products were characterized by means of FTIR and NMR spectroscopy as well as X-ray analysis.