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Development and validation of analytical methods for the determination of potential genotoxic impurities in pimavanserin active pharmaceutical ingredient
No full textPimavanserin je farmaceutik koji se koristi za liječenje halucinacija i zabluda kod psihoze povezane s Parkinsonovom bolešću. Potencijalna onečišćenja u ljekovitoj djelatnoj tvari mogu nastati tijekom procesa proizvodnje ili skladištenjem gotovog lijeka. Također, onečišćenja mogu imati genotoksični učinak, stoga je vrlo važna njihova kontrola. Svrha ovog rada je razviti i validirati analitičke metode kako bi se pouzdano mogla odrediti potencijalna genotoksična onečišćenja u pimavanserin ljekovitoj djelatnoj tvari. Tekućinska kromatografija vezana sa spektrometrijom masa (LC-MS) i plinska kromatografija vezana sa spektrometrijom masa (GC-MS) spregnute su metode koje su korištene u ovom radu. Tijekom validacije analitičkih metoda ispitani su sljedeći parametri: specifičnost, linearnost, točnost, granica detekcije, granica kvantifikacije, ponovljivost, stabilnost otopine te robusnost.Pimavanserin is a pharmaceutical used to treat hallucinations and delusions in psychosis associated with Parkinson's disease. Potential impurities in the drug active substance may occur during the manufacturing process or storage of the finished drug. Also, impurities can have a genotoxic effect, so their control is very important. The purpose of this study is to develop and validate analytical methods in order to reliably determine potential genotoxic impurities in pimavanserin drug active substance. Liquid chromatography - mass spectrometry (LC-MS) and gas chromatography - mass spectrometry (GC-MS) are the combined methods used in this work. During the validation of the analytical methods, the following parameters were examined: specificity, linearity, accuracy, limit of detection, limit of quantification, repeatability, stability of the solution, and robustness
Synthesis and characterization of (2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methyl 2-bromo-2-methylpropanoate monomer
No full textPolimeri, lanci molekula velike molekulske mase, odigrali su ključnu ulogu u razvoju tehnologije i društva. Kao rezultat napretka u istraživanju, sintezi i primjeni, polimeri se koriste široko, od medicine do elektrotehnike. Njihova raznolika svojstva, poput male gustoće, fleksibilnosti i toplinske izolacije, omogućuju prilagodbu različitim potrebama. U moderno doba, fokus se premješta prema vodljivim polimerima koji kombiniraju električnu provodljivost s drugim svojstvima. Daljnja istraživanja su ključna za optimizaciju vodljivih polimera i proširenje njihove primjene, poput nosive elektronike i solarnih ćelija, te za stvaranje inovacija u područjima kao što je elektronička koža. Jedan primjer elektrovodljivog polimera čija se primjena konstantno širi je poli(3,4-etilendioksitiofen) (PEDOT). Prilagodbom svojstava PEDOT-a putem kontroliranih metoda polimerizacije kao što su kemijska oksidacijska polimerizacija ili elektrokemijska polimerizacija, moguće je usmjeriti njegovu upotrebu za specifičnu primjenu. U sklopu ovog rada kemijskom oksidacijskom polimerizacijom sintetiziran je PEDOT-HMBr makroinicijator. Sinteza se sastojala od dva stupnja. U prvom stupnju dobiven je monomer (2,3-dihidrotieno[3,4-b][1,4]dioksin-2-il)metil 2-bromo-2-methilpropanoat (HMBr), a u drugom polimer PEDOT-HMBr makroinicijator. Karakterizacija dobivenog uzorka provedena je infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), nuklearnom magnetskom rezonancijom (NMR), termogravimetrijskom analizom (TGA) te mjerenjem električne provodnosti. Karakterizacija materijala kroz FTIR, NMR i TGA analize potvrdila je prisutnost karakterističnih skupina, omjer HMBr i EDOT jedinica te toplinsku stabilnost polimera. Električna provodnost dopiranog uzorka značajno je povećana u odnosu na čisti polimer. Unatoč postignutim rezultatima, potrebno je daljnje istraživanje kako bi se poboljšala elektrovodljivost makroinicijatora za šire mogućnosti primjene.Polymers, chains of molecules of high molecular weight, have played a key role in the development of technology and society. As a result of advances in research, synthesis and application, polymers are used widely, from medicine to electrical engineering. Their diverse properties, such as low density, flexibility and thermal insulation, allow adaptation to different needs. In modern times, the focus is shifting towards conductive polymers that combine electrical conductivity with other properties. Further research is essential to optimize conductive polymers and expand their applications, such as wearable electronics and solar cells, and to create innovations in areas such as electronic skin. One example of an electrically conductive polymer whose application is constantly expanding is poly(3,4-ethylenedioxythiophene) (PEDOT). By tailoring the properties of PEDOT through controlled polymerization methods such as chemical oxidation polymerization or electrochemical polymerization, it is possible to direct its use to a specific application. Within this study, a PEDOT-HMBr macroinitiator was synthesized by chemical oxidative polymerization. The synthesis consisted of two stages. In the first stage, the (2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methyl 2-bromo-2-methylpropanoate (HMBr) monomer was obtained, and in the second, the PEDOT-HMBr macroinitiator polymer. The obtained sample was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA) and electrical conductivity measurement. Characterization of the material through FTIR, NMR and TGA analyses confirmed the presence of characteristic groups, the HMBr to EDOT unit ratio and the thermal stability of the polymer. The electrical conductivity of the doped sample was significantly increased compared to the pure polymer. Despite achieved results, further research is required to enhance the macroinitiator's electrical conductivity for broader application possibilities
Synthesis and photochemistry of new 1,2,3-triazole stilbenes with potential anti-inflammatory activity
No full textCilj ovog rada bila je sinteza novih 1,2,3-triazolnih stiblena s potencijalnom protuupalnom aktivnosti. Za sintezu triazolnih derivata stilbena korištena je Wittigova reakcija. Općenito se ona koristi za pripravu alkena pri čemu aldehidi ili ketoni reagiraju s fosforovim ilidom. U ovom slučaju korišteni su različiti 1-supstituirani 4-formil-1,2,3-triazoli koji su reakcijom s odgovarajućim fosforovim ilidom dali 1,2,3-triazolne stilbene. Tako dobiveni produkti, zbog konjugirane dvostruke veze koju sadrže, podvrgnuti su fotokemijskim reakcijama. Prilikom osvjetljavanja sintetiziranih derivata došlo je do ciklizacije odnosno zatvaranja prstena. Elektrociklizacijski produkti testirani su na protuupalnu aktivnost. Najbolju protuupalnu aktivnost pokazao je 8-metoksi-1-(3-metoksibenzil)-1H-nafto[1,2-d][1,2,3]triazol čija
IC50 vrijednost iznosi 1,9 μM. Što je IC50 vrijednost manja, spoj je aktivniji.The aim of this work was the synthesis of new 1,2,3-triazole stilbenes with potential anti-inflammatory activity. For the synthesis of triazole derivatives of stilbenes Wittig reaction is used. It is generally used to prepare alkenes in which aldehydes or ketones react with phosphorus ylide. In this case, different 1-substitued 4-formyl-1,2,3-triazoles were used, which by reaction with the corresponding phosphorus ylide gave 1,2,3-triazole stilbenes. Products obtained in this way, because of the presence of conjugated double bond they contain, are subjected to photochemical reactions. When illuminating triazole stilbenes cyclization or closure of the ring occurred. Electrocyclization products have been tested for anti-inflammatory activity. The best anti-inflammatory activity was shown by
8-methoxy-1-(3-methoxybenzyl)-1H-nafto[1,2-d][1,2,3]triazole with IC50 value of 1.9 μM.
The compound is more active when the IC50 value is lower
Chlorine compounds as oxidanrs for advanced oxidation processes
No full textNapredni oksidacijski procesi (NOP, engl. Advanced oxidation processes, AOP) su procesi koji se koriste u svrhu razgradnje biokemijskih ili kemijskih postojanih organskih komponenata u otpadnim vodama uz određeni utrošak energije. Koriste se kao zamjena za biološke postupke pročišćavanja vode kada oni nisu djelotvorni pri uklanjanju određenih organskih komponenata. Njihova glavna uloga je mineralizacija onečišćivala i dezinfekcija voda kako bi one bile sigurne za ponovni povratak u okoliš ili za piće. Razgradnja organskih komponenata odvija se uz utrošak energije koja je potrebna za nastajanje reaktivnih međuprodukata. Napredni oksidacijski procesi se prema utrošku energije dijele u tri grupe. U grupu niske potrošnje energije spadaju procesi poput O3, O3/H2O2, O3/UV, UV/H2O2, UV/S2O82- i UV/Cl2. Druga grupa zahtijeva srednju potrošnju energije i tu spadaju foto-Fenton, plazma i elektrolitički napredni oksidacijski procesi. Treća grupa zahtijeva visoku potrošnju energije i uključuje UV-fotokatalize te procese koji se temelje na mikrovalovima i ultrazvuku. U ovom radu dan je pregled naprednog oksidacijskog procesa iz prve grupe procesa koji zahtijevaju malu potrošnju energije, UV/Cl2 procesa. Njegova učinkovitost temelji se na nastajanju HO● (hidroksil radikala) te Cl●, ClO● i Cl2●− koji imaju zajednički naziv „reaktivne vrste klora“. UV/Cl2 napredni oksidacijski proces ima svoje prednosti i nedostatke, a kao proces je relativno nov zbog čega se radi na njegovom razvoju kako bi bio što efikasniji i ekološki prihvatljiviji.Advanced oxidation processes (AOP) are processes that are used for the purpose of breaking down biochemical or chemical persistent organic components in waste water with a certain consumption of energy. They are used as a substitute for biological water purification processes when they are not effective in removing certain organic components. Their main role is the mineralization of pollutants disinfection of water so that it is safe to return to the environment or to drink. The decomposition of organic components takes place with the expenditure of energy, which is necessary for the formation of reactive intermediates. Advanced oxidation processes are divided into three groups according to energy consumption. The low energy consumption group includes processes like O3, O3/H2O2, O3/UV, UV/H2O2, UV/S2O82- and UV/Cl2. The second group requires medium energy consumption and includes photo-Fenton, plasma and electrolytic advanced oxidation processes. The third group requires high energy consumption and includes UV-photocatalysis and processes based on microwaves and ultrasound. This paper provides an overview of an advanced oxidation process from the first group of processes that require low energy consumption, the UV/Cl2 process. Its effectiveness is based on the formation of HO● (hydroxyl radicals) and Cl●, ClO● and Cl2●−, which have the common name of "reactive chlorine species". The UV/Cl2 advanced oxidation process has its advantages and disadvantages, and as a process it is relatively new, which is why it is working on its development to make it as efficient and environmentally friendly as possible
Preparation of therapeutic deep eutectic solvent
No full textNiskotemperaturna eutektička otapala su otapala za koje je karakteristično sniženje tališta s obzirom na čiste komponente od kojega su napravljene. U posljednje vrijeme, niskotemperaturna eutktička otapala se istražuju radi potencijalne primjene u farmaceutskoj industriji budući da djelatne tvari otopljene u njima ili ukomponirane u terapeutsko niskotemperaturno eutektičko otapalo imaju bolja svojstva, bolju topljivost, veću bioraspoloživost i permeabilnost u organizmu s obzirom na samu djelatnu tvar. U ovom radu, pripremljena su i karakterizirana niskotemperaturna eutektička otapala miješanjem djelatne tvari ceritiniba s različitim netoksičnim komponentama u različitim molarnim omjerima.
Svrha ovog rada je bila dobiti stabilno niskotemperaturno otapalo poboljšanih karakteristika, bolje topljivosti, bioraspoloživosti i permeabilnosti. Karakterizacija pripremljenih niskotemperaturnih otapala provedena je diferencijalnom pretražnom kalorimetrijskom analizom, dok je UV/VIS spektrofotometrijska analiza korištena je za praćenje koncentracije pri ispitivanju topljivosti. Različitim matematičkim modelima opisano je kinetičko ponašanje oslobađanja djelatne tvari iz pripremljenih niskotemperaturnih otapala.Deep eutectic solvents are solvents characterized by a lowering of the melting point considering the pure components from which they are made. Deep eutectic solvents have recently been investigated for their potential application in the pharmaceutical industry because the active pharmaceutical ingredients dissolved in them or incorporated into the therapeutic deep eutectic solvents have better properties, solubility, bioavailability, and permeability in the body than the active substance itself. In this work, deep eutectic solvents were prepared and characterized by mixing the active substance ceritinib with different non-toxic components in different molar ratios. The purpose of this work was to obtain a stable low-temperature solvent with improved characteristics, better solubility, bioavailability and permeability. Characterization of the prepared low-temperature solvents was carried out by differential scanning calorimetric analysis, while UV/VIS spectrophotometric analysis was used for monitoring concentration during the solubility test. Different mathematical models describe the kinetics and release behavior of the active substance from the prepared low-temperature solvents
Influence of printing and post-treatment parameters on epoxy resin properties used in digital light processing
No full textAditivna proizvodnja, poznata kao i 3D-ispis je tehnologija koja omogućuje stvaranje trodimenzionalnih predmeta sloj po sloj. Postupak proizvodnje započinje konstruiranjem modela u CAD (engl. Computer Aided Design) programu koji se potom sprema u STL format i prenosi na stroj za aditivnu proizvodnju. Nakon što se podese parametri stroja, započinje izrada prototipa, a nakon vađenja prototipa slijedi naknadna obrada, ako je potrebna.
Cilj ovog rada bio je odrediti utjecaj parametara izrade i postobrade na svojstva epoksidne smole korištene za 3D-ispis tehnologijom digitalne obrade svjetlom (DLP). Ova tehnologija temelji se na upotrebi 405 nm svjetla za očvršćivanje slojeva polimernog materijala. Ispitana je ovisnost mehaničkih, toplinskih i kemijskih svojstava o kutu ispisa te vremenu očvršćivanja u 405 nm komori. Smola korištena za 3D-ispis je smola na osnovi epoksida (AnyCubic 3D Printing UV Sensitive Resin). Rezultati ispitivanja pokazali su kako kut ispisa te trajanje naknadnog očvršćivanja utječu na mehanička i kemijska svojstva 3D-ispisanih epruveta. Epruvete ispisane pod kutom od 90° pokazuju najveću čvrstoću i žilavost, a najmanji modul elastičnosti. Kako se kut ispisa smanjuje, smanjuju se čvrstoća i žilavost pa tako epruvete ispisane pod kutom 0° imaju u pravilu najmanju čvrstoću i žilavost, ali najveći modul elastičnosti. Također, uzorci koji nisu naknadno obrađeni ili koji su kraće očvrsnuti pokazuju manju čvrstoću, ali veće prekidno istezanje i žilavost u odnosu na uzorke ispisane pod istim kutom, ali uz duže očvršćivanje. Ispitivanjem kemijskih svojstava bubrenjem u vodi, acetonu i metanolu može se zaključiti da svi uzorci bubre u određenoj mjeri u svim otapalima. Najveće stupnjeve bubrenja postižu uzorci bubreni u organskim otapalima acetonu i metanolu, dok voda kao anorgansko otapalo najmanje prodire u uzorke. Isto tako, primijećen je trend smanjenja apsorpcije otapala s porastom vremena izlaganja uzoraka zračenju u 405 nm komori. Prilikom ispitivanja toplinskih svojstava nije uočen značajan utjecaj parametara izrade i naknadne obrade na toplinska svojstva uzoraka. FTIR analizom potvrđene su karakteristične funkcionalne skupine i vibracije prisutne u 3D-ispisanim epruvetama te u uzorku tekuće smole.Additive manufacturing, also known as 3D printing, is a technology that enables the creation of three-dimensional objects layer by layer. The manufacturing process begins with designing a model in CAD (Computer Aided Design) software, which is then saved in STL format and transferred to the additive manufacturing machine. After setting the machine parameters, the prototype production begins, followed by post-processing if necessary.
The aim of this study was to determine the influence of manufacturing and post-processing parameters on the properties of epoxy resin used for 3D printing with digital light processing (DLP). The dependence of mechanical, thermal, and chemical properties on the printing angle and curing time in a 405 nm chamber was examined. The resin used for 3D printing is epoxy-based resin (AnyCubic 3D Printing UV Sensitive Resin). The test results showed that the printing angle and duration of post-curing have an impact on the mechanical and chemical properties of the 3D printed test samples. Test samples printed at a 90° angle exhibit the highest strength and toughness, but the lowest elastic modulus. As the printing angle decreases, the strength and toughness decrease as well, so test samples printed at a 0° angle generally have the lowest strength and toughness, but the highest elastic modulus. Additionally, samples that were not post-processed or had shorter curing times show lower strength, but higher elongation at break and toughness compared to samples printed at the same angle but with longer post-curing. By examining the chemical properties through swelling in water, acetone, and methanol, it can be concluded that all samples swell to a certain extent in all solvents. The highest degree of swelling is achieved by samples swollen in organic solvents such as acetone and methanol, while water, as an inorganic solvent, penetrates the samples to the least extent. Additionally, a trend of decreasing solvent absorption was observed with an increase in the exposure time of the samples to radiation in the 405 nm chamber. During the examination of thermal properties, no significant influence of manufacturing and post-processing parameters on the thermal properties of the samples was observed. FTIR analysis confirmed the presence of characteristic functional groups and vibrations in the 3D printed test tubes and in the liquid resin sample
Thermal and morphological properties of linear low density polyethylene/ polylactid blends
No full textPlastika je u današnje vrijeme jedan od najkorištenijih materijala i gotovo da ne možemo zamisliti svakodnevnicu bez proizvoda napravljenih od nje. Masovna uporaba plastičnih proizvoda dovela je do velike akumulacije tih proizvoda u prirodi, koji se ne mogu razgraditi te time negativno utječu na biljni i žvotinjski svijet, također i narušavaju izgled okoliša. Budući da sintetski polimeri nisu razgradljivi proizvođači polimernih materijala trebaju zamijeniti nerazgradljive polimere s ekološki prihvatljivim i biorazgradljivim polimernim materijalima koji se razgrađuju u kraćem vremenu. Linearni polietilen niske gustoće (LLDPE) ima široku primjenu kao ambalažni materijal zbog njegovih dobrih mehaničkih svojstava. Međutim nedostatak je njegova nemogućnost biorazgradnje. Koriste se različite alternative kako bi se smanjio učinak LLDP-a na okoliš, npr. miješanje termoplastičnog polimera s biorazgradljivim polimerima. PLA je biorazgradljivi polimer koji se može koristiti kao potencijalna zamjena za termoplastične polimere. Međutim njegova lomljivost (krtost) na sobnoj temperaturi predstavlja jedan od glavnih nedostataka za njegovu primjenu. Cilj ovoga rada bio je pripraviti mješavine LLDPE/PLA u omjerima 85/15 , 80/20, 75/25, 70/30, 65/35, 60/40, 55/45, 50/50 mas % u Brabender gnjetilici. Pripravljenje mješavine karakterizirane su diferencijalnom pretražnom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA),
u cilju praćenja toplinskih svojstava i toplinske stabilnosti.Plastic is nowadays one of the most widely used materials, and it's hard to imagine daily life without products made from it. The mass use of plastic products has led to a significant accumulation of these items in nature, which cannot decompose and therefore negatively interfere with the plant and animal world, also disrupting the appearance of the environment. The non-degradable nature of the synthetic polymers have forced the industries seek out other eco-friendly and biodegradable polymeric materials which are being utilized for a shorter time interval. Linear low-density polyethylene (LLDPE) are well-known because of their excellent mechanical properties they are used for the packaging industries. The lack of LLDPE is due to its inability to be biodegrade. Various alternatives are being utilized to reduce the effect of LLDPE on the environment e.g. blending of thermoplastic polymer with a biodegradable polymers. Poly(lactic) acid (PLA) is a biodegradable polymer that has attracted interest as a potential substitute for some thermoplastic polymers. However, its advanced brittleness at room temperature represents one of the major drawbacks for its general use. The aim of this study is to prepare a blend of LLDPE/PLA in ratios of 85/15, 80/20, 75/25, 70/30, 65/35, 60/40, 55/45, 50/50 wt. % using a Brabender mixer.
Thermal properties were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis
The influence of polyethylene glycol on the biocompatibility and mechanical properties of PLA/PEG carriers for use in tissue engineering
No full textSve većim razvojem tehnologije i generiranjem novih ideja danas se sve više radi na poboljšanju standarda života i produljenju životnog vijeka. U skladu s tim radi se na razvijanju biomaterijala, odnosno materijala koji mogu biti implementirani unutar ljudskog organizma kao medicinski uređaj ili implantat na način da zamijene ili potpomognu funkciju nekog organa. Tkivno inženjerstvo i proizvodnja funkcionalnih tkiva i organa dio su moderne biomedicinske znanosti. Ova grana primarno je fokusirana na zamjenu biomaterijala, koji se koriste za popravak ili zamjenu oštećenog tkiva s 3D nosačima pomoću kojih bi se moglo oštećeno tkivo obnoviti. Tijekom istraživanja provedenog za ovaj rad proučavane su polimerne mješavine polilaktida (PLA) i polietilen-glikola (PEG) kao PLA/PEG nosača. Izuzetno je važno da svaki materijal koji se koristi u medicini i dolazi u doticaj s određenim tkivom s istim bude biokompatibilan. Biokompatibilnost je sposobnost materijala da u dodiru sa živim tkivom ne izaziva oštećenje tkiva ili alergijske reakcije organizma. PLA ima odlična svojstva biokompatibilnosti i biorazgradivosti, a dodatkom PEG-a povećava se hidrofilnost, čime se utječe na bolju biorazgradivost PLA/PEG nosača. Toplinske tehnike kojima će se istražiti svojstva pripravljenih polimernih mješavina su diferencijalna pretražna kalorimetrija (DSC), termogravimetrijska analiza (TGA) kao i spektroskopska tehnika infracrvene spektroskopije s Fourierovom transformacijom (FTIR), te analiza kontaktnog kuta.With the increasing development of technologies and the generation of new ideas, today more and more people want to work on improving the standard of living and extending life expectancy. Accordingly, a lot of work is being done on the development of biomaterials, that is, materials that can be implemented inside the human organism as a medical device or implant in such a way as to replace or support the function of an organ. Tissue engineering and the production of functional tissues and organs are part of modern biomedical science. This branch of biomedicine is primarily focused on replacing biomaterials, which are used to repair or replace damaged tissue, with 3D supports that could be used to reproduce the damaged tissue. During the research conducted for this work, polymer mixtures of polylactide (PLA) and polyethylene glycol (PEG) were studied as PLA/PEG scaffolds. It is extremely important that every material that is used in medicine and comes into contact with a specific tissue is biocompatible with it. Biocompatibility is the ability of a material not to cause tissue damage or allergic reactions of the organism in contact with living tissue. PLA has excellent biocompatibility and biodegradability properties, and the addition of PEG increases hydrophilicity, which affects the better biodegradability of the PLA/PEG scaffolds.
The thermal techniques used to investigate the properties of the prepared polymer blends are differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) as well as spectroscopic technique of infrared spectroscopy with Fourier transformation (FTIR) and contact angle
The influence of temperature on the electrochemical cyclization reaction of N-benzylamides and N-benzylthioamides
No full textRazličiti derivati 4H-1,3-benzotiazina i 4H-1,3-benzoksazina zadnjih se godina intenzivno proučavaju zbog svog potencijalnog farmakološkog djelovanja. Način njihove sinteze, ali i sinteze drugih organskih molekula, sve se više okreće ka elektrokemijskoj metodi koja prednjači kada je u pitanju ekonomičnost i ekološka prihvatljivost. U ovom je radu korištena metoda elektrokemijske dehidrogenativne ciklizacije za sintezu halogeniranih derivata navedenih spojeva, pri čemu su uspješno izolirani spojevi 6a, 6a', 6b i 7a'. Praćen je utjecaj temperature, ali i drugih čimbenika, na uspješnost reakcije. Struktura svih dobivenih spojeva potvrđena je 1H-NMR spektroskopskom metodom, a mase spojeva detektirane su na
UPLC-MS/UV uređaju.In recent years, different derivatives of 4H-1,3-benzothiazine and 4H-1,3-benzoxazine have been extensively studied due to their potential pharmacological activity. The method of their synthesis, as well as the synthesis of other organic molecules, is increasingly shifting towards electrochemical methods, which excel in terms of cost-effectiveness and environmental friendliness. In this study, an electrochemical dehydrogenative cyclization method was employed for the synthesis of halogenated derivatives of the previously mentioned compounds, resulting in the successful isolation of compounds 6a, 6a', 6b, and 7a'.
The influence of temperature, among other factors, on the success of the reaction was monitored. The structure of all obtained compounds was confirmed using the 1H-NMR spectroscopic method, and the masses of the compounds were detected using a
UPLC-MS/UV device
Experimental and theoretical description of the vitamin C
No full textCilj ovog rada je pregled teorije vitamina C te izrada infracrvenog spektra za pet različitih uzoraka koji sadrže vitamin C. Prikazana su strukturna, fizikalna i kemijska svojstva ovog vitamina. Sprječava bolest skorbut pa se naziva askorbinska kiselina. Vitamin je L-enantiomer molekule. Gotovo je planarni peteročlani laktonski prsten s postraničnim lancem. Ima mogućnost reverzibilne oksidacije do dehidroaskorbinske kiseline i stvaranja relativno stabilnih slobodnih radikala te može djelovati kao sakupljač slobodnih radikala u reakcijama koje uključuju reaktivne oksidacijske vrste (ROS). Nasuprot tome, u nekim slučajevima može djelovati i prooksidativno. Albert Szent-Györgyi je 1928. godine izolirao molekulu vitamina C, a stvarnu strukturu je 1933. godine razradio Norman Haworth, nakon čega je Tadeus Reichstein objavio i patentirao komercijalno izvedivu metodu sinteze iz glukoze. Navedene su brojne funkcije i važnost kod biljaka, životinja i ljudi. Sudjeluje u zaštiti drugih antioksidansa, pomaže tijelu da apsorbira željezo, može inaktivirati i neutralizirati histamin te ima ulogu u imunološkom sustavu. Povezuje se sa zaštitom lipida, DNK i proteina od oksidansa te djeluje u mnogim mono- i dioksigenazama za održavanje metala u reduciranom stanju. Neophodan je za ispravno odvijanje fotosinteze te može kontrolirati diobu, produljenje i diferencijaciju stanica, kao i programiranu staničnu smrt. Navedene su količine vitamina C u prehrambenim izvorima te dnevne potrebe kod ljudi za sve uzraste. Kod većih doza ne dolazi do potpune apsorpcije, a velik dio apsorbirane doze se ne metabolizira i izlučuje urinom. Glavni metaboliti askorbinske kiseline u organizmu su dehidroaskorbinska kiselina, 2,3-diketo-gulonska kiselina i oksalna kiselina. Dostupne su brojne analitičke metode za opis vitamina C od kojih je u ovom radu korištena infracrvena spektroskopija s Fourierovom transformacijom. Vitamin C ima mnoge primjene u medicini te prehrambenoj, kemijskoj i kozmetičkoj industriji.The aim of this paper is to review the theory of vitamin C and to create an infrared spectrum for five different samples containing vitamin C. The structural, physical and chemical properties of this vitamin are presented. It prevents the disease scurvy, which is why it got the name ascorbic acid. Vitamin is the L-enantiomer of the molecule. It is an almost planar five-membered lactone ring with a side chain. In addition to the possibility of reversible oxidation to dehydroascorbic acid, it can form relatively stable free radicals and can act as a scavenger of free radicals in reactions involving reactive oxidizing species (ROS). On the other hand, in some cases it can also act as a pro-oxidant. Albert Szent-Györgyi isolated the vitamin C molecule in 1928, and the actual structure was worked out by Norman Haworth in 1933, after which Tadeus Reichstein published and patented a commercially viable method of synthesis from glucose. Numerous functions and importance in plants, animals and humans are listed. It participates in the protection of other antioxidants, helps the body to absorb iron, can inactivate and neutralize histamine and plays a role in the immune system. Further, it is associated with the protection of lipids, DNA and proteins from oxidants and acts in many mono- and dioxygenases to maintain metals in a reduced state. It is necessary for the proper development of photosynthesis and can control the division, elongation and differentiation of cells, as well as programmed cell death. Amounts of vitamin C in food sources and daily requirements for people of all ages are listed. With larger doses, complete absorption does not occur, and a large part of the absorbed dose is not metabolized and is excreted in the urine. The main metabolites of ascorbic acid in the body are dehydroascorbic acid, 2,3-diketo-gulonic acid and oxalic acid. Numerous analytical methods are available for the description of vitamin C, of which infrared spectroscopy with Fourier transformation was used in this work. Vitamin C has many applications in medicine as well as in the food, chemical and cosmetic industries