Sintesis senyawa E-1(-4-aminofenil)-3-(4-klorofenil)-2-propen-1-on (kalkon 1), E-3-(4-klorofenil)-1-(2,4-dimetoksifenil)-2-propen-1-on (kalkon 2), N-fenil-3-(4-klorofenil)-5-(4-aminofenil)-2-pirazolina (N-fenilpirazolina) dan 5-(4-klorofenil)-3-(2,4-dimetoksifenil)-1H-pirazol (pirazol) telah dilakukan. Senyawa kalkon disintesis melalui reaksi kondensasi Claisen-Schmidt, sementara sintesis senyawa pirazolina dilakukan melalui reaksi siklokondensasi senyawa kalkon dengan suatu hidrazin. Sintesis senyawa kalkon 1 dan 2 dilakukan dengan mereaksikan 4-klorobenzaldehida dan 4-aminoasetofenon atau 2,4-dimetoksiasetofenon dalam pelarut etanol menggunakan katalis KOH 40% dengan metode pengadukan. Tahap selanjutnya, sintesis N-fenilpirazolina dilakukan dengan mereaksikan kalkon 1 dan fenilhidrazin menggunakan katalis NaOH 40% pada suhu refluks selama 1 jam. Reaksi siklisasi terhadap kalkon 2 menggunakan hidrazin hidrat dilakukan dengan metode pengadukan selama 24 jam. Elusidasi struktur senyawa produk dilakukan menggunakan KLT, KLT scanner, FT-IR, GC-MS, 1H- dan 13C-NMR. Produk hasil sintesis diuji aktivitasnya sebagai antimalaria dengan metode penghambatan polimerisasi hem. Hasil sintesis senyawa kalkon 1, 2, N-fenilpirazolina diperoleh dengan rendemen beturut-turut sebesar 97, 94, dan 42%. Reaksi siklokondensasi antara kalkon 2 dan hidrazin hidrat menghasilkan pirazol dengan rendemen 95%. Hasil uji aktivitas antimalaria melalui penghambatan polimerisasi hem terhadap senyawa kalkon 1, 2, dan pirazol memberikan nilai IC50 berturut-turut sebesar 26,50; 56,33; dan 113,56 mM. Hasil ini menunjukkan bahwa senyawa kalkon 1 dapat menghambat terjadinya polimerisasi hematin, sehingga berpotensi sebagai agen antimalaria.

Synthesis of compound E-1(-4-aminophenyl)-3-(4-chlorophenyl)-2-propen-1-on (chalcone 1), E-3-(4-chlorophenyl)-1-(2,4-dimethoxyphenyl)-2-propen-1-on (chalcone 2), N-phenyl-3-(4-chlorophenyl)-5-(4-aminophenyl)-2-pyrazoline (N-phenylpyrazoline) and 5-(4-chlorophenyl)-3-(2,4-dimethoxyphenyl)-1H-pyrazole (pyrazole) have been carried out. Chalcone 1 and 2 were synthesized by Claisen-Schmidt condensation reaction, while the synthesis of pyrazoline compounds was done by cyclocondensation reaction of chalcone with hydrazine. The synthesis of chalcone 1 and 2 was performed by reacting 4-chlorobenzaldehyde with 4-aminoacetophenone or 2,4-dimethoxyacetophenone in ethanol using 40% KOH as a catalyst. The next step was synthesis of N-phenylpyrazoline by mixing chalcone 1 and phenylhydrazine using 40% NaOH as a catalyst under reflux for 1 h. Cyclization reaction of chalcone 2 with hydrazine hydrate. was carried out by stirring method for 24 h. Structure elucidation of the products was performed using TLC, TLC scanner, FT-IR, GC-MS, 1H-, and 13C-NMR. The synthesized products were tested for its activity as an antimalarial agent by the heme polymerization inhibition method. The product of chalcone 1, 2, and N-phenylpyrazoline was yielded in 97, 94, and 42%, respectively, while cyclocondenzation reaction of chalcone 2 with hydrazine hydrate produced pyrazole in 95% yield. The antimalarial activity test showed that inhibition of heme polymerization by chalcone 1, 2, and pyrazole give IC50 values of 26.50; 56.33; and 113.56 mM, respectively. These results indicate that chalcone 1 could inhibit the hematin polymerization so that it has potential as an antimalarial agent.

Kata Kunci : 4-klorobenzaldehida, antimalaria, kalkon, pirazolina, siklokondensasi