Study On The Synthesis And Antibacterial Activities Of7-hydroxy Coumarin Derivatives

The coumarins distributes in the umbelliferae and microorganism metabolite, it has been wildely used in the medicine, the dye and the optical material domain, due to the large range of biological activity and fluorescence performance. But with the development of the society, the natural origin is unable to meet people’s need, so the chemical synthesis of coumarins is particularly important. Twenty eight of7-hydroxy coumarin derivatives were synthesized and25of targets compounds are novel compounds. Antibacterial activities were performed for some targets compouns.The present paper divides into following four parts:1. A series of7-hydroxy coumarin were synthesized by Pechmann condensation. Six kinds of coumarins were synthesized through two ways:2-methylresorcinol and resorcinol chloride with ethyl acetoacetate or d,l-malic. The structures of1-6coumarins were comfirmed by IR, NMR and MS. The Pechmann condensation was researched through the way of d,l-malic under microwave irradiation. The optimum reaction conditions are as follows:microwave power240W, reaction time30s×5, concen-trated sulfuric aicd6mL, the ratio of2-methylresorcinol and d,l-malic aicd is1:1.2, the yields is52.2%.2. Eighteen kinds of O-alkylation coumarins were synthesized through the way of Williamson condensation. The structures of target compounds were comfirmed by IR, NMR and MS. Using tetrabutylammonium bromide (TBAB) as a phase transfer catalyst and acetone as solvent in presence of Kl, optimum conditions of Williamson reaction were as follows:n(7-hydroxy coumarin):n(alkyl halid):n(K2CO3):n(TBAB)=1.0:1.5:2.5:0.1, at60℃-100℃for4h-17h, the yields were60%-93%.3. Four coumarins containing alkyl attached to benzene ring were synthesized as material of O-allylation coumarins via classien rearrangement. The structures of4target compounds were comfirmed by IR, NMR and MS. Two different kinds heating methods are given, the result of experiment showed that the reaction would be completely in10-15min under microwave in the yields of42%-75%, but by the way of oil bath always need10-60h.4. Antibacterial activities were performed. Using Rhizoctonia solani, Gibberella zeae, Botrytis cinerea Pers, Phytophara capsici and Alternaria solani as research object,16coumarins were choiced to screen on the antibacterial activities. The results showed that coumarins with allyl structure have good antibacterial activities, especially compounds4a and5e could inhibit the growth of Rhizoctonia solani and Gibberella zeae, with an inhibitory rate more than90%.