20.500.12556/RUL-183898 Optimizacija sintezne poti za pripravo monocikličnih β-laktamov Optimization of synthetic route for the preparation of monocyclic β-lactams Pojav večkratno odpornih bakterij je postal globalni izziv, ki narekuje nujno potrebo po razvoju novih protimikrobnih učinkovin. V nalogi smo se posvetili optimizaciji sinteznih poti za pripravo beta-laktamskih antibiotikov, specifično podskupini monobaktamov oziroma 2-azetidinonov, ki smo jih kasneje biološko ovrednotili. Ti delujejo preko zaviranja sinteze peptidoglikana, kar vodi v nastanek šibkih predelov celine stene, ki posledično podležejo osmotskemu pritisku in povzročijo smrt bakterijske celice. Spojine smo pripravili z različnimi večstopenjskimi sintezami in jih očistili s kolonsko kromatografijo ter tako izdelali 7 končnih in 2 kontrolni spojini, ki smo jih testirali za zaviralno aktivnost zoper encim PBP1b iz Streptococcus pneumoniae s pomočjo fluorescenčne anizotropije in jim določili minimalno zaviralno koncentracijo na štirih sevih bakterij. Izmed treh sinteznih poti, ki so privedle do C3 substituiranega produkta, je imela najboljši celokupni izkoristek (1,4 %) pot s predhodno terc-butil karbamatno zaščitno skupino na C3 in azidom na C4. Sintezna pot do C4 substituiranega produkta pa se je izkazala za primerljivo uspešno z 0,7 % celokupnim izkoristkom, kjer smo namesto terc-butil karbamatne zaščitne skupine uporabili benzil karbamatno. Kljub majhnim izkoristkom, nam je uspelo izolirati zadostne količine produktov za biokemijsko in biološko vrednotenje. Ugotovili smo, da nobena končna spojina nima zaviralne aktivnosti zoper encim PBP1b, medtem ko sta ga obe kontrolni spojini zavirali, spojina 33 pa je dosegla tudi zaviranje rasti Gram-negativne E. coli pri testi dilucijskega antibiograma. The emergence of multi-drug-resistant bacteria has become a global challenge, necessitating the urgent development of novel antimicrobial agents. In our work, we focused on the optimization of synthetic pathways for the preparation of β-lactam antibiotics, specifically the subgroup of monobactams or 2-azetidinones, which were afterwards evaluated biologically. These types of drugs work by inhibiting peptidoglycan synthesis leading to the formation of structural weaknesses in the cell wall that subsequently succumb to osmotic pressure and result in bacterial cell death. The compounds were synthesized via various multi-step procedures and purified using liquid chromatography. In the end we prepared seven final and two control compounds, which were evaluated for their inhibitory activity against the PBP1b enzyme from Streptococcus pneumoniae using fluorescence anisotropy. Additionally, their minimal inhibitory concentrations were determined against four bacterial strains. Out of three synthetical routes used to prepare the C3-substituted product, the pathway utilizing a tert-butyloxycarbonyl protecting group at C3 and an azide group at C4 exhibited the highest overall yield (1.4%). The synthetic pathway for the C4-substituted product proved comparably successful, achieving a 0.7% overall yield using a benzyloxycarbonyl protecting group instead of the tert-butyloxycarbonyl. despite the low yields, a sufficient amount of each product was isolated for biochemical and biological evaluation. The results indicated that none of the final compounds exhibited inhibitory activity towards the PBP1b enzyme, while both control compounds inhibited the enzyme, with compound 33 also achieving satisfactory results in the microdilution antimicrobial susceptibility test by inhibiting the growth of the Gram-negative bacterium E. coli. Bakterijska odpornost beta-laktamski antibiotiki monobaktami penicilin-vezoči proteini zaviralci sinteze celične stene Bacterial resistance beta-lactam antibiotics cell wall inhibitors monobactams penicillin-binding proteins true false false [N. Pavlišič] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-06-20 08:45:07 2026-06-20 08:45:34 2026-06-23 10:57:36 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 615.33:547.7(043.2) 125535 282490883 32183.pdf 32183.pdf 1 BACF9699C13697849B365BBB910DDB3F 52775f4433c0ba750c7f39d9b3c9a71498014f13c4254ca0ac0e5f7f08c98dc0 96922ee9-6c73-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=236208 Fakulteta za farmacijo 0 0 0