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"Resistensi bakteri merupakan kemampuan bakteri bertahan hidup dari senyawa antibakteri akibat adanya mutasi. Untuk menghadapi fenomena tersebut, dibutuhkan senyawa baru yang memiliki aktivitas antibakteri dengan mekanisme penghambatan yang berbeda. 2-Kuinolon merupakan senyawa heterosiklik yang dikenal memiliki aktivitas antibakteri yang dapat diisolasi dari tanaman dan disintesis di laboratorium. Dalam studi ini, dilakukan sintesis senyawa turunan 4-metil-2-kuinolon menggunakan bantuan iradiasi microwave tanpa pelarut dari o-, m-, p-aminoanilin (fenilendiamina) serta m-hidroksianilin (m-aminofenol) dengan etilasetoasetat dan kehadiran katalis asam AlCl3 sesuai reaksi kondensasi Pechmann-like. Senyawa turunan 4-metil-2-kuinolon kemudian dianalisis aktivitas antibakterinya menggunakan metode difusi cakram terhadap Escherichia coli (gram negatif) dan Staphylococcus aureus (gram positif). Sintesis menggunakan m-aminoanilin dan m-hidroksianilin menghasilkan 7-amino-4-metil-2-kuinolon (43,42%) dan 7-hidroksi-4-metil-2-kuinolon (26,36%) dalam kondisi reaksi iradiasi microwave 800 W, rasio mol anilin:etil asetoasetat 1:1 (mol/mol), katalis 10% (b/b), dan tanpa pelarut selama 5 menit. Sintesis dari o- dan p-aminoanilin menghasilkan suatu senyawa campuran. Seluruh senyawa hasil sintesis selanjutnya diidentifikasi dengan KLT dan diuji titik lelehnya serta dikarakterisasi dengan FTIR, UV-Vis, NMR, dan LC-MS. Hasil pengujian antibakteri menunjukkan keempat senyawa hasil sintesis memiliki aktivitas antibakteri sedang terhadap E. coli dengan zona inhibisi 6-10 mm dan tidak aktif terhadap S. aureus pada rentang konsentrasi 62,5-1000 ppm. Oleh karena itu, senyawa turunan 4-metil-2-kuinolon hasil sintesis berpotensi digunakan sebagai antibakteri terhadap bakteri E. coli.

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Antibacterial resistance is an adaptive change in bacteria (mutation) that allows them to grow in the presence of an antibiotic that would normally kill them. To overcome this problem, a new antibacterial compound with different bacteria inhibition mechanisms is needed. 2-Quinolones are heterocyclic compounds with an antibacterial activity that can be isolated from plants and synthesized in the laboratory. In this study, derivatives of 4-methyl-2-quinolone are synthesized using microwave irradiation from o-, m-, p-aminoaniline (phenylenediamine), and m-hydroxyaniline (m-aminophenol) with ethyl acetoacetate in the presence of AlCl3 as a catalyst. Antibacterial activity of 4-methyl-2-quinolone derivatives were evaluated against Escherichia coli and Staphylococcus aureus using the disc diffusion method. 7-amino-4-methyl-2-quinolone (43,42%) and 7-hydroxy-4-methyl-2-quinolone (26,36%) were obtain from m-aminoaniline dan m-hydroxyaniline precursor, respectively, under conditions of 800 W microwave irradiation without solvent for 5 minutes, mole ratio of aniline: ethyl acetoacetate 1:1 (mole/mole), and 10% (w/w) catalyst. Synthesis of derivatives 4-methyl-2-quinolone from o- and p-aminoaniline produce a mixed compound. All synthesized compounds were identified by TLC and melting points, followed by further characterization using FTIR, UV-Vis, NMR, and LC-MS. The results of the antibacterial test showed that the four synthesized compounds had moderate antibacterial activity against E. coli with 6-10 mm of inhibition zone and inactive against S. aureus in the range of 62.5-1000 ppm concentration. Therefore, the derivatives of 4-methyl-2-quinolone have the potential to an antibacterial against E. coli bacteria."

"Senyawa 7-hidroksi-4-metilkumarin (hymecromone) merupakan senyawa heterosiklik turunan kumarin yang memiliki banyak aktivitas biologis. Hymecromone disintesis melalui reaksi kondensasi Pechmann antara resorsinol dan etil asetoasetat dengan variasi katalis asam dan metode. Katalis asam heterogen zeolit disintesis melalui reaksi kalsinasi dari NH4/MOR, NH4/Y dan NH4/USY dan katalis H-ZSM-5 didapat secara komersil lalu dikarakterisasi dengan FT-IR, NH3-TPD, XRD, SEM-EDX, dan BET. Katalis asam homogen yang digunakan adalah H3BO3 dan AlCl3 sebagai asam Lewis serta asam p-toluensulfonat monohidrat (PTSA.H2O) dan H2SO4 sebagai asam Brønsted. Reaksi dijalankan dengan metode konvensional (pengadukan), Microwave Assisted Organic Synthesis (MAOS), dan Ultrasound Assisted Organic Synthesis (UAOS) dengan variasi jumlah katalis, suhu, dan waktu reaksi. Kemudian produk dikarakterisasi dengan FT-IR, UV-Vis, NMR, dan LC/MS. Katalis heterogen H/Y memberikan yield optimum sebesar 8,06% dengan kondisi reaksi perbandingan mol reaktan 1:1, jumlah katalis 10 wt%, waktu 9 jam, suhu 80 oC menggunakan metode konvensional. Zeolit H/Y kemudian digunakan dalam studi reaksi recycle sebanyak 3 kali menggunakan metode UAOS dan menunjukkan kemampuan untuk digunakan berulang kali. Katalis homogen PTSA.H2O memberikan yield optimum sebesar 76,15% dengan kondisi reaksi perbandingan mol reaktan 1:1, konsentrasi katalis 10%, waktu 3 menit, suhu 70 oC menggunakan metode MAOS. Zeolit memberikan pilihan alternatif untuk katalis yang ramah lingkungan, mudah dipisahkan, dan dapat digunakan berulang kali.

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7-Hydroxy-4-methyl coumarin (hymecromone) is a heterocyclic coumarin with a wide range of biological activities. In this study, hymecromone was successfully synthesized by reacting resorcinol and ethyl acetoacetate with several acidic catalysts using various methods. Acidic zeolite catalysts were synthesized by calcination of NH4/MOR, NH4/Y, and NH4/USY, while H/ZSM-5 were commercially obtained. All zeolites then were characterized by FT-IR, NH3-TPD, XRD, SEM-EDX, and BET. The homogenous catalysts used were H3BO3 and AlCl3 as Lewis acids, as well as p-toluene sulfonic acid monohydrate (PTSA.H2O) and H2SO4 as Brønsted acids. Reactions were conducted using conventional heating with stirring, Microwave-Assisted Organic Synthesis (MAOS), and Ultrasound-Assisted Organic Synthesis (UAOS) with variations in catalyst amount, temperature, and reaction times. The product was characterized using FT-IR, UV-Vis, NMR, and LC/MS. The heterogeneous catalyst H/Y afforded an optimum yield of 8.06% with the reaction conditions as follows: 1:1 (mole/mole) of reactant ratio, 10 wt% of catalyst, 9 hours of reaction time at 80oC using a conventional method. H/Y was recycled 3 times and showed good recyclability. The homogenous catalyst PTSA.H2O gave the optimum yield of 76.15% with the reaction conditions as follows: 1:1 (mole/mole) of reactant ratio, concentration catalyst of 10%, 3 minutes of reaction time at 70oC using the MAOS method. In conclusion, zeolites offer an alternative for a more environmentally friendly catalyst that is easy to separate and recyclable."

"Kumarin merupakan kelompok senyawa heterosiklik yang secara alami terdapat pada tanaman. Senyawa turunan kumarin telah banyak disintesis dan beberapa di antaranya memiliki aktivitas antibakteri. Di sisi lain, resistensi bakteri terhadap antibiotik mendesak agar penelitian tentang senyawa yang berpotensi sebagai antibakteri terus dikembangkan. Oleh karena itu, pada penelitian ini disintesis senyawa turunan 4-metil kumarin dan dianalisis aktivitas antibakterinya terhadap Escherichia coli dan Staphylococcus aureus berdasarkan studi literatur. Bakteri E. coli dan S. aureus merupakan dua bakteri paling umum yang memiliki resistensi terhadap antibiotik. Senyawa turunan 4-metil kumarin yang berhasil disintesis adalah 7-hidroksi-4-metil kumarin dari reaksi kondensasi Pechmann antara resorsinol dan etil asetoasetat dengan katalis SnCl2.2H2O menggunakan metode Microwave Assisted Organic Synthesis (MAOS) dengan persentase yield optimum sebesar 49,85 ± 5,4% dengan kondisi reaksi rasio mol resorsinol/etil asetoasetat 1:1, 10% mol katalis terhadap resorsinol, waktu reaksi 260 detik, dan tanpa pelarut. Senyawa hasil sintesis telah diidentifikasi dengan KLT dan uji titik leleh, serta dikarakterisasi dengan menggunakan FTIR, UV-Vis, dan NMR (1D dan 2D). Sintesis senyawa turunan 4-metil kumarin lainnya dari katekol dan hidrokuinon sebagai pengganti resorsinol tidak berhasil dilakukan yang menunjukkan kereaktifan kedua senyawa dihidroksibenzena tersebut lebih rendah dibandingkan dengan resorsinol. Berdasarkan studi literatur, senyawa turunan 4-metil kumarin, 6-hidroksi- dan 7-hidroksi-4-metil kumarin, memiliki aktivitas antibakteri terhadap bakteri E. coli. Senyawa 7-hidroksi-4- metil kumarin juga dilaporkan memiliki aktivitas antibakteri terhadap S. aureus. Oleh karena itu, senyawa turunan 4-metil kumarin yang disintesis pada penelitian ini diharapkan memiliki potensi sebagai agen antibakteri.

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ABSTRACTCoumarin is classified as a group of heterocyclic compounds naturally found in plants. Coumarin and its derivatives have been widely synthesized and shown antibacterial activities. On the other hand, antibiotic resistance of some bacterial strains has urged the research development related to the new antibacterial agents. Accordingly, in this study, 4-methyl coumarin derivatives were synthesized and its antibacterial activities were also evaluated against Escherichia coli and Staphylococcus aureus based on literary study. Both bacteria are the most common multidrug-resistant bacteria. 7-Hydroxy-4-methyl coumarin was successfully synthesized via Pechmann condensation between resorcinol and ethyl acetoacetate with SnCl2.2H2O as catalyst using MAOS method. The synthesized compound was obtained with an optimum yield of 49,85 ± 5,4% under solvent free reaction with resorcinol/ethyl acetoaceate molar ratio of 1:1 (mol/mol), 10 mol% catalyst, and 260s reaction time. The synthesized product was identified by TLC and melting point apparatus, and further characterized by using FTIR, UV-Vis, and NMR (1D and 2D) instruments. However, other 4-methyl coumarin derivatives from catechol and hydroquinone to substitute resorcinol were failed to synthesize revealing that they have low reactivity compared to resorcinol in Pechmann condensation. Based on literary studies regarding its antibacterial activities, 4-methyl coumarin derivatives, i.e. 6- hydroxy- and 7-hydroxy-4-methyl coumarin showed good activity towards E. coli. In addition, 7-hydroxy-4-methyl coumarin was also reported having antibacterial activity against S. aureus. Therefore, 4-methyl coumarin derivatives may have potency as antibacterial agent."