The alpha-oxo ketene dithioacetalic derivatives (2a-e) were obtained by the reaction of 2-acetylpyrazine (1) with CS2 and appropriate mono- or dihalogeno-compound. An action of the primary amines and diamines upon 3,3-di(methylsulphanyl)-1-(2-pyrazinyl)-2-propen-1-one (2a) yielded 3-(alkylamino)-3-(methylsulphanyl)-1-(2-pyrazinyl)-2-propen-1-on e (3a-g), 1-(2-pyrazinyl)-2-tetrahydro-1H-2-imidazolyliden-1-ethanone (3h) and the 2-hexahydro-2-pyrimidinyliden-1-(2-pyrazinyl)-1-ethanone derivatives (3i-j), respectively. Tuberculostatic activity of the studied compounds was found to be low except the compound 2b (MIC 192-62 micrograms/cm3; MIC 210-31 micrograms/cm3).