SINTESIS NITROPIRAZOLINA DARI BENZALDEHIDA DAN UJI AKTIVITASNYA SEBAGAI ANTIBAKTERI

LENNI MARGIYANI, Dra. Tutik Dwi Wahyuningsih, M.Si., Ph.D.; Deni Pranowo, S.Si., M.Si.

2014 | Skripsi | KIMIA

Sintesis nitropirazolina dari benzaldehida dan uji aktivitasnya sebagai antibakteri telah dilakukan dengan diawali reaksi nitrasi benzaldehida, kondensasi aldol antara nitrobenzaldehida dan asetofenon membentuk khalkon, kemudian siklisasi khalkon dengan fenilhidrazina membentuk senyawa nitropirazolina. Pirazolina hasil sintesis diuji aktivitasnya sebagai antibakteri terhadap Staphylococcus aureus dan Eschericia coli. Reaksi nitrasi benzaldehida dilakukan dengan cara mereaksikan asam nitrat dan benzadehida dengan katalis asam sulfat. m-Nitrobenzaldehida direaksikan dengan asetofenon pada suhu ruang sehingga terbentuk senyawa 3-nitrokhalkon. Sintesis nitropirazolina dilakukan dengan mereaksikan 3-nitrokhalkon dan fenilhidrazina dalam pelarut asam asetat glasial dengan refluks selama 2,5 jam. Semua produk hasil sintesis dianalisis menggunakan FTIR, GC-MS dan 1H-NMR. Uji antibakteri dilakukan terhadap bakteri S. aureus (bakteri gram positif) dan E. coli (bakteri gram negatif) dengan kontrol positif kloramfenikol dan kontrol negatif DMSO. Hasil sintesis memberikan rendemen m-nitrobenzaldehida sebesar 32,32%, 3-nitrokhalkon 55,69% dan nitropirazolina sebesar 41,99%. Dari uji antibakteri yang telah dilakukan menunjukkan bahwa nitropirazolina hasil sintesis tidak aktif terhadap bakteri S. aureus dan E. coli.

Synthesis and antibacterial activity of nitropyrazoline from benzadehyde have been investigated. The reaction was began by nitration of benzaldehyde, aldol condensation between nitrobenzaldehyde and acetophenone followed by cyclization of chalcone by addition of phenilhidrazine. Nitration of benzaldehyde was carried out by reacting nitric acid, sulfuric acid and benzaldehyde at 15 oC. m-Nitrobenzaldehyde was reacted with acetophenone at room temperature in alkaline condition to give 3-nitrochalcone. Synthesis of pyrazoline was performed by refluxing 3-nitrochalcone and phenilhidrazine in acetic acid glacial for 2.5 hour . All products were analyzed using FTIR, GC-MS and 1H-NMR spectrometers. Antibacterial test was integrated to S. aureus (gram positive bacteria) and E. coli (gram negative bacteria), chloramphenicol as positive control and DMSO as negative control. The result showed that synthesis of m-nitrobenzaldehyde produced yellow solid in 32.32% yield, while 3-nitrochalcone was yielded in 55.69% and cyclization reaction gave nitropyrazoline as yellow solid in 41.99%. Antibacterial test showed that pyrazoline is inactive against bacteria S. aureus and E. coli

Kata Kunci : nitropirazolina, 3-nitrokhalkon, benzaldehida, antibakteri