A new series of thiazole compounds are synthesized and theirs anticancer activity was tested against breast cancer cells MCF7. The starting ethyl 2-(4-hydroxyphenyl)-4-methylthiazole-5-carboxylate was alkylated by alkyl bromides in DMF. The resulted ethyl 4-methyl-2-(4-(alkyloxy)phenyl)thiazole-5-carboxylate compounds were refluxed with hydrazine hydrate in ethanol to afford 4-methyl-2-(4-(alkyloxy)phenyl)thiazole-5-carbohydrazide compounds. These hydrazides were reacted with various cyclizing reagents to give various 1,3,4-oxadiazole and pyrazole-ring containing thiazole compounds. The antiproliferative activity was calculated on the basis of IC50 values. The (5-amino-3-phenyl-1H-pyrazol-1-yl)(4-methyl-2-(4-(ethoxy)phenyl)thiazol-5-yl)methanone has comparable activity with standard Paclitaxel.