Homolytic alkylation of 6-chloro-2-pyrazinecarbonitrile by alkanoic acid and subsequent partial hydrolysis afforded 5-alkyl-6-chloro-2-pyrazinecarboxamides 1a-1e. Reaction of amides 1a-1e by Lawesson's reagent afforded corresponding thioamides 2a-2e. The structure of compounds was confirmed by elemental analysis, IR and 1H NMR spectra. The assessment of in vitro antimycobacterial activity of the compounds was carried out. The highest antituberculotic activity against Mycobacterium tuberculosis and other mycobacterial strains in this series was shown by 5-(1,1-dimethylethyl)-6-chloro-2-pyrazinecarbothioamide (2e).