Facile synthesis of bis-thiosemicarbazone derivatives as key precursors for the preparation of functionalised bis-thiazoles

A new class of bis-thiosemicarbazones was designed and synthesised by the condensation of 2,6-diformylphenol derivatives and thiosemicarbazide using either ultrasound or conventional methods. Both thiosemicarbazone groups of these derivatives underwent a heterocyclisation process to give a series of novel bis-thiazole derivatives as major products. The structures of all the synthesised compounds were characterised by multinuclear NMR (1H and 13C), IR, HRMS and elemental analyses.