SINTESIS 3,4-DIMETOKSI-6-NITROKHALKON DAN 3,4-DIMETOKSIKHALKON SERTA UJI AKTIVITASNYA SEBAGAI ANTIOKSIDAN

Rizania Irmawati, Dr. Winarto Haryadi, M.Si ; Prof. Drs. Sabirin Matsjeh, Ph.D

2019 | Skripsi | S1 KIMIA

Telah dilakukan sintesis senyawa 3,4-dimetoksi-6-nitrokhalkon dan 3,4-dimetoksikhalkon serta uji aktivitasnya sebagai antioksidan. Senyawa 6-nitroveratraldehida diperoleh dari hasil reaksi nitrasi senyawa veratraldehida dengan HNO3 dan H2SO4. Senyawa khalkon disintesis melalui reaksi kondensasi Claisen-Schmidt. Sintesis senyawa 3,4-dimetoksi-6-nitrokhalkon (khalkon 1) dilakukan dengan mereaksikan asetofenon, 6-nitroveratraldehida dan katalis basa NaOH 8% dalam pelarut etanol selama 4 jam. Sintesis senyawa 3,4-dimetoksikhalkon (khalkon 2) dibuat dengan mereaksikan asetofenon dan veratraldehida dalam pelarut etanol menggunakan katalis KOH 13% selama 20 jam. Elusidasi struktur produk dilakukan menggunakan spektrofotometer FT-IR, DI-GC-MS, TLC Scanner, 1H-NMR dan 13C-NMR. Senyawa khalkon hasil sintesis diuji aktivitas antioksidannya menggunakan metode DPPH dengan asam askorbat sebagai kontrol positif. Produk sintesis nitrasi veratraldehida menghasilkan senyawa 6-nitroveratraldehida berupa padatan berwarna kuning dengan persentase hasil 86,77% dan titik leleh 110-113 ºC. Sintesis senyawa khalkon 1 menghasilkan padatan berwarna hijau dengan persentase hasil 30,62% dan titik leleh 173-176 ºC. Sintesis senyawa khalkon 2 menghasilkan padatan berwarna kuning dengan persentase hasil 48,97% dan titik leleh 78-79 ºC. Hasil uji aktivitas antioksidan senyawa khalkon 1 dan khalkon 2 memiliki nilai IC50 berturut-turut 19,972 µg/mL dan 31,177 µg/mL yang dapat dikategorikan sebagai antioksidan kuat.

Synthesis of 3,4-dimethoxy-6-nitrochalcone and 3,4-dimethoxychalcone compounds and activity test as antioxidant have been carried out. The 6-nitroveratraldehyde compound was obtained from the nitration reaction of veratraldehyde compound with HNO3 and H2SO4. Synthesis of chalcone was carried out by Claisen-Schmidt condensation reaction. The 3,4-dimethoxy-6-nitrochalcone (chalcone 1) compound was synthesized by reacting acetophenone, 6-nitroveratraldehyde and NaOH 8% catalyst in ethanol stirred for 4 hours. The 3,4-dimethoxychalcone (chalcone 2) compound was synthesized by reacting acetophenone and veratraldehyde with ethanol as solvent using a KOH 13% catalyst stirred for 20 hours. Elucidation of product structure was performed using FT-IR spectrofotometer, DI-GC-MS, TLC Scanner, and 1H-13C-NMR. The chalcone compound synthesized was tested for its antioxidant activity using DPPH method with ascorbic acid as positive control. The veratraldehyde nitration synthesis produced 6-nitroveratraldehyde compound in the form of yellow solid with yield 86.77% and melting point 110-113 ºC. Synthesis of chalcone 1 compound produced a green solid with yield 30.62% and melting point 173-176 ºC. Synthesis of chalcone 2 compound produced a yellow solid with yield 48.97% and melting point 78-79 ºC. The results of activity test for chalcone 1 and chalcone 2 as antioxidant gave IC50 19.972 µg / mL and 31.177 µg / mL respectively and both chalcones have activity as strong antioxidant.

Kata Kunci : Kata kunci : antioksidan, asetofenon, khalkon, nitroveratraldehida. / Keyword : antioxidant, acetophenone, chalcone, nitroveratraldehyde.