Sintesis, Karakterisasi dan Uji Aktivitas Antibakteri Turunan Senyawa 3,5-Diaril-2-Pirazolina-1-Karbaldehida Berbahan Dasar Veratraldehida

PUTRI NUR FADHILLA, Dra. Tutik Dwi Wahyuningsih, M. Si., Ph. D. ; Dr. Chairil Anwar

2015 | Skripsi | S1 KIMIA

Telah dilakukan sintesis, karakterisasi dan uji aktivitas antibakteri turunan senyawa 3,5-diaril-2-pirazolina-1-karbaldehida berbahan dasar veratraldehida. Penelitian ini dilakukan dengan tujuan untuk mempelajari sintesis turunan senyawa 3,5-diaril-2-pirazolina-1-karbaldehida dan uji aktivitas antibakterinya terhadap beberapa bakteri Gram positif dan Gram negatif. Penelitian ini diawali dengan melakukan sintesis senyawa 1-(2,4-dihidroksifenil)-3-(3,4-dimetoksifenil)-2-propen-1-on (kalkon) melalui reaksi kondensasi Claisen Schmidt antara veratraldehida, 2,4-dihidroksiasetofenon dan KOH 40% (b/b) pada temperatur ruang selama 48 jam. Selanjutnya senyawa kalkon hasil sintesis direaksikan dengan hidrazin monohidrat dalam asam format menggunakan metode refluks selama 24 jam untuk menghasilkan senyawa 3-(2,4-dihidroksifenil)-5-(3,4-dimetoksifenil)-2-pirazolina-1-karbaldehida (pirazolina). Elusidasi struktur senyawa hasil sintesis dilakukan menggunakan spektrometer FTIR, GC-MS, 1H- dan 13C-NMR. Senyawa pirazolina diuji aktivitas antibakterinya menggunakan metode difusi sumuran pada agar terhadap beberapa bakteri Gram positif yaitu Bacillus subtilis, Bacillus cereus dan Staphylococcus aureus serta bakteri Gram negatif yaitu Escherichia coli dan Shigella flexneri. Reaksi kondensasi Claisen Schmidt menghasilkan senyawa kalkon berupa padatan berwarna kuning dengan rendemen sebesar 19,27%. Senyawa pirazolina berupa padatan berwarna kuning kehijauan telah berhasil disintesis menghasilkan rendemen sebesar 81,87%. Uji antibakteri menunjukkan bahwa senyawa pirazolina menunjukkan aktivitas sebagai antibakteri pada bakteri Gram positif dan Gram negatif yang diujikan dengan nilai DDH (mm)/konsentrasi senyawa uji (ppm) terbaik pada bakteri Gram positif Bacillus subtilis (5,25/1000) dan bakteri Gram negatif Shigella flexneri (4,75/1000).

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 : Kata kunci: kalkon, 2-pirazolina-1-karbaldehida, antibakteri, veratraldehida