Synthesis and Antibacterial Activities of N-Substituted Pyrazole Curcumin Derivatives

In order to find new lead compounds for the design of new antibacterial drugs, 13 novel N-substituted pyrazole curcumin derivatives were synthesized from curcumin and substituted hydrazide. The structures of all new compounds were confirmed by H-1 NMR, C-13 NMR, IR, MS techniques and elemental analysis. The results of their in vitro antibacterial tests indicated that, at the concentration of I X 10(-4) mol/L, all of the derivatives displayed better activities than curcumin against B. subtilis, S. (wrens, E. coli, A. niger, and Penicillium, ch. The compounds 3,5-bis(4-hydroxy-3-methoxystyryl)-1-amidinoparazole (3c), 3,5-bis(4-hydroxy-3-methoxystyryl)-1-(banzothiazol-2-sulfenyl)parazole (3k) and 3,5-bis(4-hydroxy-3-methoxystyryl)-1-(coumarin-3-formoryl)parazole (3m) showed remarkable antibacterial activities (with inhibition zone of up 16.34 to 23.81 mm). The results showed that thiazole ring, or guanyl and coumarin ring substituents may enhance the activities of N-substituted pyrazole curcumin derivatives.