| Abstract | U ovom doktorskom radu opisana je sinteza, strukturna karakterizacija i biološka aktivnost novih derivata 2-arilbenzimidazola i 2-arilbenzotiazola, hidrazonskih derivata benzotiazola te 1,2,3-triazolnih derivata kumarina i iminokumarina. U sintezama su pored konvencionalnih metoda korištene i ekološki prihvatljive zelene metode poput sinteza potpomognutih mikrovalovima i ultrazvukom te mehanokemijske reakcije. Ultrazvukom potpomognutom reakcijom ciklokondenzacije pripravljenih O-alkiliranih benzaldehida (1‒6) ili 1,2,3-triazolnih derivata benzaldehida (10 i 11) s različito supstituiranim 1,2-diaminobenzenima uz Na2S2O5 kao oksidacijsko sredstvo, pripravljeni su novi O-alkilirani (12‒27) i 1,2,3-triazolni derivati 2-arilbenzimidazola (28‒33). Derivati 2-(4-alkoksifenil)benzotiazola (47–55) sintetizirani su konvencionalnim načinom reakcijom O-alkiliranja priređenih 2-(4-hidroksifenil)benzotiazola (40–46) s odgovarajućim aminoalkil-halogenidima uz K2CO3, dok su derivati
2-(4-alkoksifenil)-6-halobenzotiazola (56–67) pripravljeni mikrovalovima potpomognutom reakcijom O-alkiliranja 2-(4-hidroksifenil)benzotiazola (43–46). Bakrom kataliziranom Huisgenovom 1,3-dipolarnom cikloadicijom morfolinskog azida (9) i sintetiziranih derivata 2-(4-O-(propargilfenil)benzotiazola (68–74) pripravljeni su 1,2,3-triazolni derivati benzotiazola (75–81). U svrhu odabira metode sinteze derivata 2- i 3-O-(1-aril-1,2,3-triazolil)fenilbenzotiazola (88‒117) provedeno je optimiranje reakcijskih uvjeta na modelnoj klik reakciji s azidobenzenom uključujući konvencionalnu, mehanokemijsku i sintezu potpomognutu ultrazvukom. Mehanokemijskom klik reakcijom uz pomoć kapljevine su postignuta najveća iskorištenja benzotiazolnih derivata (88, 98 i 108) uz najkraće vrijeme trajanja reakcije te je mehanokemija odabrana kao metoda za pripravu 2- i 3-O-(1-aril-1,2,3-triazolil)fenilbenzotiazola (88‒117) te derivata 2-(4-O-(1-aril-1,2,3-triazolil)fenil)benzotiazola (118‒156). Hibridi benzotiazola i 4-alkilaminobenzena povezani hidrazonskom spojnicom (169–202) pripravljeni su kao E-izomeri mehanokemijskom sintezom bez otapala reakcijom kondenzacije sintetiziranih 4-alkoksibenzaldehida (1, 2, 4, 5, 161‒168) i 2-hidrazinilbenzotiazola (158–160). Mikrovalovima potpomognutom klik reakcijom kataliziranom bakrom iz odgovarajućih azida i terminalnih alkina sintetizirani su 1,2,3-triazolni iminokumarinski (207–212) i kumarinski derivati (213–223). Pripravljenim derivatima strukture su potvrđene spektroskopijom 1H- i 13C-NMR kao i dvodimenzijskim metodama NOESY, HSQC i HMBC. Antiproliferativna aktivnost in vitro pripravljenim spojevima ispitana je na nizu humanih tumorskih staničnih linija te na zdravim stanicama. Antibakterijska aktivnost in vitro je ispitana na Gram-pozitivnim i Gram-negativnim bakterijskim sojevima uključujući klinički rezistentne sojeve MRSA i VRE. Derivatima benzotiazola s 1,4-disupstituiranim
1,2,3-triazolnim prstenom (88‒97, 108‒117 i 118–156) ispitana je i antivirusna aktivnost. Kako bi se utvrdila moguća korelacija između antiproliferativne i antioksidativne aktivnosti, derivatima koji su pokazali izraženu antiproliferativnu aktivnost ispitana je antioksidativna aktivnost in vitro metodom DPPH. Od svih ispitanih spojeva najizraženiju antiproliferativnu aktivnost in vitro su pokazali: 2-(4-(2-N,N-dietiletoksi)-3-fluorfenil)-6-klorbenzimidazol (23) (K-562, Z-138, IC50 = 2.0 μM), 2-(4-(N,N-dietiletoksi)-3-metoksifenil)-6-klorbenzotiazol (59) (CFPAC, IC50 = 1.03 μM) i (E)-2-(3-(4-(N,N-dimetiletoksi)-3-fluorfenil)hidrazonil)-6-klorbenzotiazol (188) (CAPAN, IC50 = 0.6 μM, NCI-H460, IC50 = 0.9 μM). Najsnažniju selektivnu antibakterijsku aktivnost su pokazali derivati 2-(4-alkoksifenil)-6-klorbenzimidazola (15‒17) prema Enterococcus faecalis (MIC = 0.25‒1 mg/mL) te 2-(4-(N,N-dietiletoksi)fenil)-6-klorbenzotiazol (50) koji je pokazao najizraženiju aktivnost prema soju MRSA 13276
(MIC = 2 μg/mL). Najizraženiju antivirusnu aktivnost pokazao je triazolni derivat 2-klorbenzotiazola (89) prema virusu gripe H1N1 (EC50 = 6.7 μM). |
| Abstract (english) | This doctoral thesis describes the synthesis, structural characterization and biological activity of new derivatives of 2-arylbenzimidazole and 2-arylbenzothiazole, hydrazone derivatives of benzothiazole and 1,2,3-triazole derivatives of coumarin and iminocoumarin. In addition to conventional synthetic methods, ecologically acceptable green methods were also used, such as synthesis assisted by microwaves, ultrasound and mechanochemical reactions. Ultrasound-assisted cyclocondensation reaction of prepared O-alkylated benzaldehydes (1‒6) or 1,2,3-triazole derivatives of benzaldehyde (10 and 11) with differently substituted 1,2-diaminobenzenes in the presence of Na2S2O5 as an oxidizing agent, gave new O-alkylated (12 ‒27) and 1,2,3-triazole derivatives of 2-arylbenzimidazole (28‒33).
2-(4-alkoxyphenyl)benzothiazole derivatives (47–55) were synthesized conventionally by O-alkylation reaction of prepared 2-(4-hydroxyphenyl)benzothiazole (40–46) with corresponding aminoalkyl halides in the presence of K2CO3, while 2-(4-alkoxyphenyl)-6-halobenzothiazole derivatives (56–67) were prepared by microwave-assisted O-alkylation reaction of 2-(4-hydroxyphenyl)benzothiazole (43–46). Copper-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of morpholine azide (9) and 2-(4-O-(propargylphenyl)benzothiazole derivatives (68–74) gave 1,2,3-triazole derivatives of benzothiazole (75–81). In order to select the synthetic metod of target 2-arylbenzothiazole derivatives substituted at different position of the benzene ring with 1,2,3-triazole ring (88–117), optimization of the reaction conditions was conducted on a model reaction including conventional synthesis, ultrasound-assisted synthesis and mechanochemical synthesis. Since the liquid assisted mechanochemical reactions gave the highest yields of benzothiazole derivatives (88, 98 and 108) with the shortest reaction time, mechanochemistry was selected as the method for the preparation of 2- and 3-O-(1-aryl-1,2,3-triazolyl))phenylbenzothiazole (88‒117) and
2-(4-O-(1-aryl-1,2,3-triazolyl)phenyl)benzothiazole derivatives (118‒156). Hybrids of benzothiazole and 4-alkylaminobenzene bridged by a hydrazone moiety (169–202) were prepared as an E-isomers using solvent-free mechanochemical synthesis by condensation reaction of 4-alkoxybenzaldehydes (1, 2, 4, 5, 161‒168) and 2-hydrazinylbenzothiazoles (158–160). 1,2,3-triazole iminocoumarin (207–212) and coumarin derivatives (213–223) were synthesized by copper-catalyzed microwave-assisted click reaction of the corresponding azides and terminal alkynes. The structures of the prepared derivatives were confirmed by 1H- and 13C-NMR spectroscopy as well as by two-dimensional methods NOESY, HSQC and HMBC. The antiproliferative activity in vitro of the prepared compounds was evaluated against a range human tumor cell lines as well as on healthy cells. Antibacterial activity in vitro was performed on Gram-positive and Gram-negative bacterial strains including clinically resistant strains of MRSA and VRE. Benzothiazole derivatives with a 1,4-disubstituted 1,2,3-triazole ring (88‒97, 108‒117 and 118–156) were also tested for antiviral activity. In order to establish a possible correlation between antitumor and antioxidative activity, derivatives that showed pronounced antiproliferative activity were evaluated for antioxidant activity in vitro by the DPPH method. Among all the prepared derivatives the most significant antiproliferative activity in vitro showed 6-chloro-2-(4-N,N-diethyl-3-fluorophenyl)benzimidazole (23) (K-562, Z-138, IC50 = 2.0 μM), 6-chloro-2-(4-N,N-diethyl-3-methoxyphenyl)benzothiazole (59) (CFPAC, IC50 = 1.03 μM) and (E)-6-chloro-2-(3-(4-(N,N-dimethylethoxy)-3-fluorophenyl)hidrazonyl)benzothiazole (188) (CAPAN,
IC50 = 0.6 μM, NCI-H460, IC50 = 0.9 μM). The strongest selective antibacterial activity was shown by 2-(4-alkoxyphenyl)-6-chlorobenzimidazole derivatives (15‒17) on Enterococcus faecalis (MIC = 0.25–1 mg/mL) and 6-chloro-2-(4-N,N-diethylphenyl)benzothiazole (50), which showed the most pronounced activity against MRSA strain 13276 (MIC=2 μg/mL). Triazole derivative of 2-chlorobenzothiazole (89) showed the strongest antiviral activity against influenza virus H1N1 (EC50 = 6.7 μM). |
