Abstract: Substituted pyrazine derivatives were synthesized and tested against Mycobacterium tuberculosis strain H37Rv. The hydrophobicity of all the pyrazines was determined using the reversed phase high performance liquid chromatography (RP-HPLC) method (isocratic elution with methanol as an organic modifier in the mobile phase, end-capped non-polar C18 stationary RP column). Experimentally derived Log K values (the logarithm of capacity factor K) were that compared with Log P values calculated by commercially available programmes. The synthetic approach, analytical, spectroscopic, lipophilicity and biological data of ten newly synthesized compounds are presented. Structure—activity relationships among the chemical structure, the anti-mycobacterial activity of the evaluated compounds are discussed. 3-(3-Methylphenyl)-aminopyrazine-2,5-dicarboxamide (7) has shown the highest activity against M. tuberculosis H37Rv (63% inhibition).