Sinteza i spektroskopska karakterizacija novih derivata imidazo[4,5-b]piridina kao potencijalnih senzora za pH u otopinama

undergraduate thesis

• Title (english): Synthesis and spectroscopic characterization of novel imidazo[4,5-b]pyridine derivatives as potential sensors for pH in solutions
• Author: Leonarda Frljak
• Mentor: Marijana Hranjec (mentor)
• Committee member: Marijana Hranjec (predsjednik povjerenstva)
• Committee member: Dragana Vuk (član povjerenstva)
• Committee member: Petar Kassal (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

U sklopu ovog rada provedene su sinteze novih derivata imidazo[4,5-b]piridina. Željeni spojevi 8-13 pripremljeni su standardnim metodama organske sinteze, kao i reakcijama potpomognutim mikrovalovima. 5-brom-N-metil-3-nitropiridin-2-amin 3 priređen je nekataliziranom aminacijom početnog 5-brom-2-klor-3-nitropiridina 1. Redukcijom 5-brom-N-metil-3-nitropiridin-2-amina 3 uz korištenje kositrovog klorida dihidrata u etanolu, priređen je diamino supstituirani prekursor 4. 2-fenil supstituirani derivati, 6-brom-3-metil-2-fenil-3H-imidazo[4,5-b]piridin 6 i 6-brom-2-fenil-3H-imidazo[4,5-b]piridin 7 priređeni su kondenzacijom diamino supstituiranih piridina 4 i 5 s benzaldehidom uz p-benzokinon. Željeni konačni 6-(p-fenil) supstituirani spojevi 8-11 priređeni su iz početnih 6-brom supstituiranih derivata imidazo[4,5-b]piridina 6 i 7 u Suzukijevoj reakciji uz korištenje tetrakis(trifenilfosin)paladija(0) kao katalizatora, kalijevog karbonata kao baze u sustavu otapala dioksan/voda. Spoj 4-(6-(metilamino)-5-nitropiridin-3-il)benzonitril 12 priređen je iz početnog spoja, 5-brom-N-metil-3-nitropiridin-2-amina 3. Spoj 13 je priređen reakcijom reduktivne ciklizacije s benzaldehidom uz korištenje natrijevog ditionita u smjesi otapala etanol i DMSO. Strukture spojeva potvrđene su 1H NMR i 13C NMR spektroskopijom. Željeni spojevi 8-13 karakterizirani su UV/Vis spektroskopijom u otapalima različitih polarnosti. Promjene u spektroskopskim svojstvima otopina spojeva promatrane su pH titracijama u puferima različitih pH vrijednosti. Na taj način provedena ispitivanja potvrdila su mogućnosti primjene ovakvih derivata kao optičkih pH senzora.

Abstract (english)

This work presents the synthesis of novel imidazo[4,5-b]pyridine derivatives. Targeted compounds 8-13 were prepared using standard methods of organic synthesis, as well as by microwave-assisted reactions. 5-bromo-N-methyl-3-nitropyridin-2-amine 3 was prepared by uncatalyzed amination of starting 5-bromo-2-chloro-3-nitropyridine 1. Within the reduction of 5-bromo-N-methyl-3-nitropyridin-2-amine 3 using stannous chloride dihydrate in ethanol, the diamino substituted precursor 4 was prepared. 2-phenyl substituted derivatives, 6-bromo-3- methyl-2-phenyl-3H-imidazo[4,5-b]pyridine 6 and 6-bromo-2-phenyl-3H-imidazo[4,5- b]pyridine 7 were prepared by condensation of diamino substituted pyridines 4 and 5 with benzaldehyde with p-benzoquinone. The preferred 6-(p-phenyl) substituted compounds 8-11 were prepared from the 6-bromo substituted imidazo[4,5-b]pyridine derivatives 6 and 7 in the Suzuki reaction using tetrakis(triphenylphosine)palladium(0) as a catalyst, and potassium carbonate as a base in the dioxane/water solvent system. Compound 4-(6-(methylamino)-5- nitropyridin-3-yl)benzonitrile 12 was prepared from the starting compound, 5-bromo-Nmethyl- 3-nitropyridin-2-amine 3. Compound 13 was prepared by a reductive cyclization reaction with benzaldehyde by using sodium dithionite in a solvent mixture of ethanol and DMSO. The structures of the compounds were confirmed by 1H NMR and 13C NMR spectroscopy. Preferred compounds 8-13 were characterized by UV/Vis spectroscopy in solvents of different polarities. Changes in the spectroscopic properties of the compounds solution were observed by pH titrations using buffers of different pH values. The obtained results confirmed the possible application of these derivatives as optical pH sensors.

• Keywords: imidazo[4 5-b]piridin; NMR spektroskopija; UV/Vid spektroskopija; pH senzori; optički senzori; Suzukijeva reakcija
• Keywords (english): imidazo[4 5-b]pyridine; NMR spectroscopy; UV/Vis spectroscopy; pH sensors; optical sensors; Suzuki reaction
• Language: croatian
• URN:NBN: urn:nbn:hr:149:985071
• Project: Number: IP-2018-01-4379; Title: Istraživanje antioksidativnog djelovanja benzazolskog skeleta u dizajnu novih antitumorskih agensa; Acronym: AntioxPot; Leader: Marijana Hranjec; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Project: Number: IP-2020-02-8090; Title: Dizajn, sinteza i računalna analiza novih optičkih kemijskih pH osjetilnih derivata benzazola; Title: Design, Synthesis and Computational Analysis of Novel Optical Chemical pH Sensing Benzazole Derivatives; Acronym: BenzpHSens; Leader: Robert Vianello; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Chemical Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-02-23 06:38:41