SINTESIS TURUNAN 1-FENIL-3-(4'-NITROFENIL)-5-ARIL-2-PIRAZOLINA DARI VANILIN DAN UJI ANTIBAKTERINYA SECARA IN-VITRO
LINA FAUZI'AH, Dr. Tutik Dwi Wahyuningsih, M.Si; Dr. Bambang Purwono, M.Sc
2014 | Tesis | S2 Ilmu KimiaTelah dilakukan sintesis turunan senyawa 1-fenil-3-(4'nitrofenil)-5-aril-2-pirazolina dan uji antibakterinya secara in-vitro. Sintesis senyawa pirazolina dilakukan melalui reaksi sikloadisi antara 1,3-difenil-2-propen-1-on (kalkon A, B dan C) dengan fenilhidrazina. Senyawa kalkon disintesis dari vanilin dan turunannya (veratraldehida dan 6-nitroveratraldehida) dengan 4-nitroasetofenon melalui kondensasi Claisen Schmidt dengan NaOH sebagai katalis. Senyawa kalkon A disintesis dari vanilin menggunakan NaOH 60% (b/v dalam akuades) melalui pengadukan selama 24 jam pada temperatur kamar. Senyawa kalkon B dan C disintesis dengan pengadukan campuran veratraldehida dengan NaOH 15% dan 6-nitroveratraldehida dengan NaOH 5% (b/v dalam etanol) masing-masing selama 4 dan 6 jam. Pirazolina B disintesis dengan merefluks kalkon dan fenilhidrazina dalam etanol dengan katalis asam asetat glasial selama 6 jam. Pirazolina A dan C direfluks dalam pelarut 2-butanol masing-masing selama 30 dan 24 jam. Produk hasil sintesis dikarakterisasi dengan spektrometer FTIR, GC-MS, 1H- dan 13C-NMR. Uji antibakteri dilakukan dengan metode difusi sumuran terhadap bakteri Gram positif (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis) dan Gram negatif (Eschericia coli, Shigella flexneri) dengan kontrol positif tetrasiklin (100 ppm) dan kontrol negatif dimetilsulfoksida DMSO (99,9%). Hasil penelitian menunjukkan bahwa senyawa kalkon A, B dan C telah berhasil disintesis dengan rendemen berturut-turut sebesar 16,80; 75,83 dan 44,11%. Senyawa target pirazolina A, B dan C telah berhasil disintesis dengan rendemen berturut-turut sebesar 45,07; 53,80 dan 33,06%. Hasil uji antibakteri senyawa pirazolina menunjukkan bahwa perbedaan substituen mempengaruhi aktivitas antibakteri. Pirazolina A, B dan C memiliki aktivitas yang paling tinggi terhadap S. flexneri dengan diameter zona hambat berturut-turut 5,75 (500 dan 1000 ppm), 5,75 (500 ppm) dan 9,25 mm (1000 ppm).
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 : kalkon, pirazolina, antibakteri
