SINTESIS, KARAKTERISASI DAN UJI AKTIVITAS ANTIBAKTERI TURUNAN SENYAWA 3,5-DIARIL-2-PIRAZOLINA-1-KARBALDEHIDA BERBAHAN DASAR VERATRALDEHIDA; SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY TEST OF 3,5-DIARYL-2-PYRAZOLINE-1-CARBALDEHYDE DERIVATIVE FROM VERATRALDEHYDE

Fadhilla, Putri Nur, Tutik Dwi Wahyuningsih

2015 | Skripsi | FMIPA

Synthesis, characterization and antibacterial activity test of 3,5-diaryl-2-pyrazoline-1-carbaldehyde derivative have been conducted. The aims of this research are to study the synthesis of 3,5-diaryl-2-pyrazoline-1-carbaldehyde derivative and its antibacterial activity test against several Gram positive and Gram negative bacteria. This research begins with a synthesis of 1-(2,4-dihydroxyphenyl)-3-(3,4-dimethoxyphenyl)-2-propene-1-one (chalcone) by Claisen Schmidt condensation reaction of veratraldehyde, 2,4-dihydroxyacetophenone and KOH 40% (b/b) at room temperature for 48 hours. Furthermore, chalcone synthesized is reacted with hydrazine monohydrate in the presence of formic acid under reflux for 24 hours to produce 3-(2,4- dihydroxyphenyl)-5-(3,4- dimethoxyphenyl)-2-pyrazoline-1-carbaldehyde (pyrazoline). The structure elucidation of the synthesized compounds was confirmed by FTIR, GC-MS, 1H- dan 13C-NMR spectrometers. The pyrazoline was tested for antibacterial activity by agar well-diffusion against Gram positive bacteria such as Bacillus subtilis, Bacillus cereus and Staphylococcus aureus as well as Gram negative bacteria, namely Escherichia coli and Shigella flexneri. Claisen Schmidt condensation reaction has produced a yellow solid of chalcone compound with 19.27% yield. The greenish yellow pyrazoline compound has been synthesized to give 81.87% yield. Antibacterial test showed that pyrazoline was active against selected Gram positive and Gram negative bacteria with the best zone of inbition (mm)/concentration of the test compound (ppm) in Gram positive bacteria Bacillus subtilis (5.25/1000) and Gram negative bacteria Shigella flexneri (4.75/1000).

Kata Kunci : chalcone; 2-pyrazoline-1-carbaldehyde; antibacterial; veratraldehyde