SINTESIS DAN UJI ANTIBAKTERI SENYAWA TURUNAN 4'-HIDROKSIKALKON DAN PIRAZOLINA DARI SENYAWA TURUNAN BENZALDEHIDA

LINCE DAMERIA BR NADAPDAP, Dr. Tutik Dwi Wahyuningsih, M.Si.; Dr. Winarto Haryadi, M.Si.

2016 | Tesis | S2 Ilmu Kimia

Senyawa turunan 4'-hidroksikalkon, yakni (E)-3-(4-hidroksi-3-metoksifenil)-1-(4-hidroksifenil)-2-propena-1-on (1a), (E)-3-(3,4-dimetoksifenil)-1-(4-hidroksifenil)-2-propena-1-on (1b) dan (E)-1-(4-hidroksifenil)-3-(4-metoksifenil)-2-propena-1-on (1c) telah disintesis berturut-turut dari 3 senyawa turunan benzaldehida yakni 4-hidroksi-3 metoksibenzaldehida (a); 3,4-dimetoksibenzaldehida (b) dan 4-metoksibenzaldehida (c), masing-asing direaksikan dengan 4-hidroksiasetofenon melalui reaksi kondensasi Claisen-Schmidt pada kondisi basa. Selanjutnya senyawa turunan pirazolina, yakni 4-(4-hidroksi-3-metoksifenil)-3-(4-hidroksifenil)-4,5-dihidro-1H-pirazol-1-karbaldehida (2a), 5-(3,4-dimetoksifenil)-3-(4-hidroksifenil)-4,5-dihidro-1H-pirazol-1-karbaldehida (2b) dan 3-(4-hidroksifenil)-5-(4-metoksifenil)-4,5-dihidro-1H-pirazol-1-karbaldehida (2c) disintesis dari reaksi siklisasi senyawa turunan 4'-hidroksikalkon yang telah dihasilkan dengan 4-hidrazin monohidrat dan asam format. Semua senyawa turunan 4'-hidroksikalkon dan pirazolina hasil sintesis dikarakterisasi fisika - kimianya dan struktur kimia senyawanya dianalisis menggunakan spektrometer FT-IR, GC-MS, 1H- dan 13C-NMR serta aktivitas antibakteri diuji menggunakan metode sumuran. Hasil reaksi kondensasi Claisen-Schmidt antara turunan benzaldehida (a, b, dan c) dan 4-hidroksiasetofenon dalam suasana basa NaOH 40% menggunakan pelarut metanol yang direfluk selama 18 jam menghasilkan senyawa turunan 4'-hidroksikalkon (1a, 1b dan 1c) dengan rendemen berturut-turut 96,20; 96,37 dan 96,87%. Hasil reaksi siklisasi antara senyawa turunan 4'-hidroksikalkon dengan hidrazin monohidrat dan asam format yang direfluk selama 18 jam mampu menghasilkan senyawa turunan pirazolina (2a, 2b, dan 2c) dengan rendemen berturut-turut sebesar 96,12; 89,94; dan 96,24%. Berdasarkan hasil pengujian aktivitas antibakteri terhadap senyawa 4'-hidroksikalkon, senyawa 1a mampu menghambat pertumbuhan bakteri B. cereus pada konsentrasi 600-1000 ppm. Senyawa 1b dan 1c mampu menghambat pertumbuhan bakteri B. subtilis, B. cereus, E. coli dan S. flexneri pada konsentrasi yang sama, rata-rata 600-1000 ppm, tetapi 1c menunjukkan hasil yang lebih baik dibandingkan 1b. Hasil uji antibakteri terhadap senyawa pirazolina 2a, 2b, dan 2c tidak menunjukkan hasil positif terhadap bakteri, baik Gram positif maupun Gram negatif.

Syntheses of 4'-hydroxychalcone (1a, 1b, and 1c), ie. (E)-3-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenil)-2-propena-1-on (1a), (E)-3-(3,4-dimethoxyphenil)-1-(4-hydroxyphenyl)-2-propena-1-on (1b) dan (E)-1-(4-hydroxyphenyl)-3-(4-methoxyphenyl)-2-propena-1-on (1c) were synthesized from benzaldehyde derivatives, ie. 4-hydroxy-3-methoxybenzaldehyde (a), 3,4-dimethoxybenzaldehyde (b), and 4-methoxybenzaldehyde (c) through reaction of Claisen-Schmidt condensation. Fuhermore, pyrazoline derivatives, ie. 4-(4-hydroxy-3-methoxyphenyl)-3-(4-hydroxyphenyl)-4,5-dihydro-1H-pyrazol-1-carbaldehyde (2a), 5-(3,4-dimethoxyphenyl)-3-(4-hydroxyphenil)-4,5-dihydro-1H-pirazol-1-carbaldehyde (2b) dan 3-(4-hydroxyiphenyl)-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-1-carbaldehyde (2c) were synthesized by cyclization reaction of the resulted 4'-hydroxychalcone derivatives with hydrazine monohydrate and formic acid. All of 4'-hydroxychalcone and pyrazoline derivatives compound were characterized by physicochemical and their chemical structures were established by FT-IR, GC-MS, 1H- and 13C-NMR spectrometer and the antibacterial activity were evaluated by well-difusion method. The result of reaction through Claisen-Schmidt condensation between benzaldehyde derivatives (a, b and c) with 4-hydroxyacetophenone under NaOH 40% alkaline and methanol as solvent using reflux for 18 hours, obtained 4'-hydroxychalcone derivatives (1a, 1b, and 1c), repectively 96.20; 96.37 and 96.87%. The result of cyclization reaction between 4'-hydroxychalcone derivatives with hydrazine monohydrate and formic acid were produced by reflux for 18 hours and obtained pirazoline derivatives, respectively 96.12; 89.94 and 96.24%. Based on the result of antibacterial test of 4'-hydroxychalcones compound, 1a compound had capability for inhibition the growth of B. cereus bacteria at concentration of 600-1000 ppm. 1b and 1c compounds were showed their capability for inhibition all the growth of bacterias at concentration average on 600-1000 ppm, but 1c compound found the result better than 1b. The result of antibacteria test for pyrazoline derivatives (2a, 2b, 2c) did not show positive result against the bacterias, both Gram positive and Gram negative bacteria.

Kata Kunci : Vanilin, Veratraldehida, p-Anisaldehida, 4'-Hidroksikalkon, Pirazolina, Antibakteri