SINTESIS TURUNAN 1-FENIL-3-(4'-NITROFENIL)-5-ARIL-2- PIRAZOLINA DARI VANILIN DAN UJI ANTIBAKTERINYA SECARA IN-VITRO; SYNTHESIS OF 1-PHENYL-3-(4'-NITROPHENYL)-5-ARYL-2-PYRAZOLINE DERIVATIVES FROM VANILLIN AND ITS IN-VITRO ANTIBACTERIAL TEST

Lina Fauzi’ah, Tutik Dwi Wahyuningsih

2014 | Disertasi | PROGRAM STUDI S2 KIMIA

Synthesis of 1-phenyl-3-(4'nitrophenyl)-5-aryl-2-pyrazoline derivatives and its antibacterial activity have been carried out. The synthesis of pyrazolines were performed via cycloaddition of 1,3-diphenyl-2-propen-1-on (chalcones A, B, and C) and phenylhydrazine. Chalcones were synthesized from vanillin and its derivatives (veratraldehyde and 6-nitroveratraldehyde) with 4-nitroacetophenone by Claisen Schmidt condensation with NaOH as catalyst. Chalcone A was synthesized from vanillin using NaOH 60% (w/v in aquadest) under stirring at room temperature for 24 h. Chalcone B and C were produced by stirring the mixture of veratraldehyde with NaOH 15% and 6- nitroveratraldehyde with NaOH 5% (w/v in ethanol) for 4 and 6 h, respectively. Synthesis of pyrazoline B was performed by refluxing chalcone B and phenylhydrazine in glacial acetic acid for 6 h. In addition, Pirazolines A and C were refluxed in 2-buthanol for 30 and 24 h, respectively. All the synthesized compounds were characterized using FTIR, GC-MS 1H- and 13C-NMR spectrometers. Antibacterial tests were carried out by agar well-diffusion against Gram positive (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis) and negative (Eschericia coli, Shigella flexneri) bacteries, tetracycline (100 ppm) as positive control and dimethylsulfoxide (DMSO 99.9%) as negative control. The result showed that chalcones A, B and C have been succesfully synthesized in 16.80; 75.83 and 44.11% yield, respectively. Furthermore, the cycloaddition reaction yielded the pyrazoline A, B and C in 45.07; 53.80 and 33.06%, respectively. Antibacterial test of pyrazoline compounds showed that the substituent differences affect antibacterial activity. Pyrazoline compounds (A, B and C) have the highest activity againts S. flexneri with inhibition zone were 5.75 (500 and 1000 ppm), 5.75 (500 ppm) and 9.25 mm (1000 ppm).

Kata Kunci : chalcone, pyrazoline, antibacterial