SINTESIS DAN UJI AKTIVITAS ANTIBAKTERI SENYAWA PIRAZOLINA BERBAHAN DASAR 3-METOKSI-4-HIDROKSIBENZALDEHIDA (VANILIN) DAN 4-METOKSIBENZALDEHIDA (p-ANISALDEHIDA); SYNTHESES AND ANTIBACTERIAL ACTIVITIES OF PYRAZOLINES FROM 3-METHOXY-4-HYDROXYBENZALDEHYDE (VANILLIN) AND 4-METHOXYBENZALDEHYDE (p-ANISALDEHYDE)
Putra, Haryadi N, Chairil Anwar
2015 | Skripsi | FMIPA UGMSyntheses of pyrazoline derivatives and their antibacterial activities have been done. The pyrazolines that have been synthesized were N-phenyl-3-(4-chlorophenyl)-5-(4-hydroxy-3-methoxy-5-nitrophenyl)-2-pyrazoline (pyrazoline 1), N-phenyl-3-(4-hydroxyphenyl)-5-(4-hydroxy-3-methoxy-5-nitrophenyl)-2-pyrazoline (pyrazoline 2), and N-phenyl-3-(2,4-dihydroxyphenyl)-5-(4-methoxyphenyl)-2-pyrazoline (pyrazoline 3). Pyrazolines 1, 2, and 3 were synthesized by reflux method with glacial acetic acid as a catalyst. Both pyrazoline 1 or 2 were synthesized through cyclocondensation reaction between 1-(4-chlorophenyl)-3-(4-hydroxy-3-methoxy-5-nitrophenyl)-2-propen-1-on (chalcone 1) and 1-(4-hydroxyphenyl)-3-(4-hydroxy-3-methoxy-5-nitrophenyl)-2-propen-1-on (chalcone 2) with phenyl hydrazine, whereas pyrazoline 3 was synthesized through the cyclocondensation method, between 1-(2,4-dihydroxyphenil)-3-(4-methoxyphenyl)-2-propen-1-on (chalcone 3) and hydrazine monohydrate. Chalcones 1 and 2 were synthesized through Claisen Schmidt condensation method of 4-hydroxy-3-methoxy-5-nitrobenzaldehyde (nitrovanillin) with 4-chloroacetophenone and with 4-hydroxyacetophenone using catalyst of NaOH 40% (w/v), whereas chalcone 3 was synthesized from 4-methoxybenzaldehyde (p-anisaldehyde) and 2,4-dihydroxyacetophenone using catalyst of KOH 60% (w/v). Nitrovanillin was obtained by nitration of vanillin using calcium nitrate (Ca(NO3)2). The products of syntheses were analyzed by FTIR, GC-MS, 1H- and 13C-NMR. The antibacterial activity test was only performed on pyrazoline 3 because pyrazoline 3 has the highest purity than pyrazolines 1 and 2. The antibacterial activities test has been done with “wells diffusion method” using Gram positive bacteria (S. aureus, B. cereus, and B. subtillis) and Gram negative bacteria (E. coli and S. flexneri), also DMSO 99% as a negative control and tetracycline (100 ppm) as a positive control. The result from nitration of vanillin showed that nitrovanillin was obtained at 95.95% yield. On the other hand, Claisen Schmidt condensation has produced chalcones 1, 2, and 3 with the yield of 94.60%; 47.17%; and 30.34%, whereas products of pyrazolines 2 and 3 were 42.86% and 71.43%. Pyrazoline 3 showed good antibacterial activity both in Gram positive and Gram negative bacteria. The highest activity showed at 500 ppm for S. aureus and B. cereus, also 1000 ppm for B. subtillis, E. coli and S. flexneri.
Kata Kunci : pyrazoline; chalcone; vanillin; p-anisaldehyde; antibacterial activity.
