Substituted thiazoles VI. Synthesis and antitumor activity of new 2-acetamido- and 2 or 3-propanamido-thiazole analogs

► 2-Acetamido and 2-propanamido derivatives of 4- or 5-substituted-thiazoles were designed and synthesized. ► In-vitro antitumor activity of the new compounds was evaluated. ► Compounds 23 and 27 proved lethal to Leukemia CCRF-CEM cell line. ► Compound 37 proved lethal to non-small cell lung HOP-92, NCI-H522 and Breast MDA-MB-468 cancers. ► Compounds 37, 41 and 42 are the most active broad spectrum antitumor agents.