2,4-Disubstituted thiazoles II. A novel class of antitumor agents, synthesis and biological evaluation

A series of 2,4-disubstituted thiazole derivatives bearing N-n-butyl or N-cyclohexylthioureido synthon at position 2 and N-substituted thiosemicarbazone moiety at position 4 have been synthesized and tested for antitumor activity using the National Cancer Institute's in-vitro-disease-oriented antitumor screen. All of the tested compounds showed antineoplastic activity at concentrations less than 100 μM. Compounds 7, 9, 15 and 17 in particular showed activity with GI₅₀ (mean-graph midpoint) of 17.8, 8.5, 9.5 and 7.4 μM, respectively. The detailed syntheses, spectroscopic and biological data are discussed.