Naslov
Application of green chemistry methods in synthesis of biologically active heterocyclic compounds

Autori
Markulinčić, Marko ; Đukić, Katarina ; Komar, Mario ; Lončarić, Melita ; Jakovljević, Martina ; Prkačin, Mirjana ; Molnar, Maja

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
5th International Cholnoky Symposium

Mjesto i datum
Pečuh, Mađarska, 24.04.2019. - 25.04.2019

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
deep eutectic solvents ; heterocycles ; green chemistry

Sažetak
Introduction: A synthesis of biologically active compounds for potential application in medicine, pharmacy, cosmetic industry, have been intensified in the last few decades. Not only it became desirable to find a new synthetic paths for the synthesis of such heterocyclic compounds, the focus has been put on finding the synthetic routes with the minimal adverse impact on the environment. When utilizing a green chemistry procedures and methods in the synthesis, one can be guided by the green chemistry principles. Deep eutectic solvents (DES), as a green solvents, fit these green chemistry principles, since they are synthesized from non-toxic and cheap biodegradable components, with 100% atom economy. They are formed from the hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD), mixed together in various ratios, to form a eutectic mixture. DES have been extensively used in a wide range of synthetic transformations, both as the solvents and catalysts. Our work is focus on choline chloride based DES which were successfully applied for the synthesis of different heterocyclic compounds. Materials and methods DES synthesis: an equimolar amount of choline chloride and corresponding HBD is mixed together and heated to 80 °C until a clear liquid is formed. Thus synthesized DES is used in the synthesis of desired compounds without further purification. N-Acetylation of different amines: Amines and acetic anhydride are mixed together (1:1.2 molar ratio) and added to choline chloride:urea (1:2) DES. The reaction was monitored by TLC, yielding acetylated amines in good to excellent yields. Synthesis of mercapto quinazolinones: An equimolar amount of anthranilic acid and various isothiocyanates was added to corresponding DES and stirred until the completion of reaction monitored on TLC. Synthesis of coumarinyl Schiff bases: an equimolar amount of coumarinyl hydrazide and substituted aldehydes was mixed together and stirred until all reactatns were consumed. A solid product precipitated upon addition of water. One-pot synthesis of 1, 2, 4-triazoles: Coumarinyl hydrazides and substituted isothiocyanates were mixed and stirred in DES until the completion of reaction. Water was added and the solid product precipitated. Results and discussion Since DES can be synthesized from different HBA and HBD, their physical and chemical properties vary greatly, depending on the components mixed together, so they can be referred to as tunable solvents. Their ability to be recycled for several times without adverse effect on the reaction products makes them even more desirable in synthetic chemistry. They have been successfully applied for the synthesis of different heterocyclic compounds with no need for catalysts. N-Acetylated amines were successfully synthesized in good to excellent yields in this improved reaction, since the amount of acetic anhydride which is often used in these kind of reactions, was drastically reduced. Mercapto quinazolinones were successfully synthesized in choline chloride:urea DES with no need for catalysts, which are usually utilized in this kind of reaction. Obviously, DES can serve as a solvent and as catalyst as well. Coumarinyl Schiff bases were also synthesized in good to excellent yields, with no need for addition of acetic acid as a catalyst. One-pot synthesis of 1, 2, 4-triazoles was also performed, with no catalysts needed, form corresponding hydrazide and isothiocyanates. Deep eutectic solvents were proven to be an excellent reaction media for all these reactions, while the isolation of the products was very easy, and included only the addition of water and filtration.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Prehrambena tehnologija

POVEZANOST RADA