Synthesis of 4-Arylidene-3-Methyl-1-(4-Phenylthiazol-2-yl)-1H-Pyrazol-5(4H)-Ones through a Four-Component Condensation

A novel method for thiazolyl-pyrazolone rings formation is established using the reaction of phenacyl bromide and thiosemicarbazide with ethyl acetoacetate in the presence of aryl aldehyde to give 4-arylidene-3-methyl-1-(4-phenylthiazol-2-yl)-1H-pyrazol-5(4H)-ones in good yields.