Study On The Synthesis Of The Substituted2’,4’-dihydroxy Chalcone Thioscmicarbazone And Its Derivatives

This paper aims at designing and synthesizing new Schiff bases, aromatic hydrazone-thiazole and Mannich bases with hydroxyl chalcone (or flavanone) and thiosemicarbazide skeleton by substituted2’,4’-dihydroxy chalcone and thiosemicarbazide condensed in different ways. All the structures were characterized by IR, MS, NMR techniques. The main research contents are as follows:1.The structure, activity and research progresses of chalcone., flavanone, thiosemicarbazide, aromatic hydrazone-thiazole and their derivatives were briefly reviewed.2.Substituted2’,4’-dihydroxy chalcone were synthesized without hydroxyl protection by microwave assisted. The chalcone were then condensed with thiosemicarbazide in MeOH-H2O, catalyzed by glacial acetic acid to afford new flavanone-thiosemicarbazide Schiff base in one-pot via a chalcone-thiosemicarbazide condensation and a chalcone intramolecular cyclization. The feeding ratio, alcohol/water volume ratio, reaction temperature, reaction time and pH of the reaction were studied.3.Phenacyl bromide was synthesized with acetophenone and bromide, then condensed with flavanone-thiosemicarbazide Schiffs base in anhydrous methanol to afford new flavanone aromatic hydrazone thiazole.4.Designed and studied the synthesizing of2’,4’-dihydroxy chalcone-thiosemicarbazide Mannich bases from the following two routes:(1) The direct method,2’-4’dihydroxy chalcone, formalin solution and thiosemicarbazide were heated in refluxed ethanol to afford2’,4’-dihydroxy chalcone-thiosemicarbazide Mannich bases;(2) The indirect method,2,4-dihydroxy acetophenone Mannich base were firstly synthesized with2,4-dihydroxy acetophenone, formalin solution and thiosemicarbazide, then condensed with different substituted phenylaldehyde to afford2’,4’-dihydroxy chalcone-thiosemicarbazide Mannich bases via aldol reaction. The difference and application of these two routes were also discussed.