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Wide commercial application of azo pyridone dyes rests on the cost-effectiveness of their preparation and almost innumerable possibilities for the synthesis by combining various diazo and coupling pyridone components that enable tuning of targeted properties. The great significance of these dyes in the last few decades is due to their outstanding properties, such as vivid colors and good color fastness properties. Azo pyridone dyes are also applicable in different coloration related processes such as inkjet printing and liquid crystal displays. On the other hand, they are recognized as valuable compounds in biological studies, as they possess antioxidant, antimicrobial and antiproliferative properties. In this work, three novel 6-hydroxy-4-methyl-1-pyridinium-2-pyridone based dyes bearing three bioactive heterocyclic rings in their structures are synthesized, wherein thiazole based anilines (2-aminothiazole, 2-aminobenzothiazole, 6-methoxy-2-aminobenzothiazole) are used as diazo components. The compounds are characterized by melting points, NMR and FTIR spectroscopy. The solvatochromic properties are investigated in solvents of different properties. Furthermore, the antioxidant capacities of the compounds are evaluated by ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) assay, while antimicrobial activity is determined by broth microdilution method against five bacterial strains (S. aureus, E. faecalis, B. subtilis, E. coli and K. pneumoniae) and one fungal strain (C. albicans)., Široka komercijalna upotreba piridonskih azo boja zasniva se na njihovoj relativno jeftinoj i jednostavnoj pripremi, kao i činjenici da se veliki broj kuplujućih i diazo komponenti mogu međusobno kombinovati kako bi se dobile boje odgovarajućih svojstava. Veliki značaj ovih boja poslednjih nekoliko decenija, ogleda se u njihovim istaknutim svojstvima kao što su živopisna obojenja i dobra postojanost. Ove boje, takođe, nalaze primenu u ink-džet štampi i LCD ekranima. Sa druge strane, ove boje predstavljaju značajna jedinjenja u biološkim studijama, jer poseduju antioksidativnu, antimikrobnu i antiproliferativnu aktivnost. U ovom radu, sintetisane su tri boje koje u svojoj strukturi obuhvataju tri bioakativna heterociklična jezgra, pri čemu je kao kuplujuća komponenta korišćen 6-hidroksi-4-metil-1-piridinijum-2-piridon, a kao diazo komponente anilini na bazi tiazola (2-aminotiazol, 2-aminobenzotiazol i 6-metoksi-2-aminobenzotiazol). Jedinjenja su okarakterisana temperaturom topljenja, NMR i FTIR spektroskopijama. Solvatohromna svojstva su ispitana u rastvaračima različitih svojstava. Antioksidativna aktivnost jedinjenja ispitana je ABTS (2,2'-azino-bis-3-etilbenzotiazolin-6-sulfonat) testom, dok je minimalna inhibitorna koncentracija ispitana primenom mikrodilucione metode u bujonu prema 5 bakterijskih sojeva (S. aureus, E. faecalis, B. subtilis, E. coli i K. pneumoniae), kao i prema oportunističkoj gljivici C. albicans.

Hydrogels have unique properties and many potential applications, particularly in medicine and biotechnology. Gel porosity and swelling properties, stability, and biocompatibility are charac-teristics that are widely variable and easily adjusted. Stimuli-responsive or intelligent hydrogels are a class of thesematerials that shows a significant response to small changes in the surrounding environment. Poly(N-isopropylacrylamide) (PNiPAAm) is the best-known thermosensitive polymer with a well-defined volume phase transition temperature (VPTT) around 32C. On theother hand, silver nanoparticles (AgNPs) have been the subject of intense interest due to their size-dependent optical, catalytic, and electronic properties as well as remarkable antimicrobial potential. Within the last decade, scientists have demonstrated that anisotropic AgNPs can be synthesized in a controlled manner and that these materials exhibit distinctively different physicochemical properties from their spherical counterparts. A significant challenge that scientists face is establishing how thesenanoparticles can be used in a wider spectrum of practical applications. Therefore, we pre-sent a simple, straightforward two-step synthesis of AgNPs/PNiPAAm hydrogel nanocomposites that includes the chemical formation of both spherical and triangular AgNPs, followed by gamma irradiation-induced PNiPAAm crosslinking in the presence of nanoparticles. The gamma irradia-tion technique merges sterilization and synthesis in a single technological step, optimizing the pro-cess and opening up a wide range of innovative biomedical applications. The formation of stable and uniformly distributed AgNPs in the polymer was confirmed by UV-VIS spectroscopy, while the network porous sponge-like structure was observed by SEM analysis. Physicochemical characteri-zation was performed by examining the swelling and deswelling processes in water at 25C and 48C, respectively. In addition, AgNPs were shown to have an effect on VPT, Hidrogelovi su materijali koji poseduju specifičnu poroznost, stabilnost, biokompatibilnost i sposobnost apsorpcije okolne tečnosti, kao i svojstva koja su promenljiva i lako podesiva širokom spektru primena, naročito u oblasti medicine i biotehnologije. Posebno je interesantna oblast “inteligentnih“ hidrogelova, odnosno materijala koji reaguju na spoljašnje stimulanse i pokazuju značajanu fizičku ili hemijsku promenu pri malim promenama u okruženju. Poli(N-izopropilakrilamid) (PNiPAAm) je najpoznatiji termosenzitivni polimer sa jasno definisanom temperaturom faznog prelaza (VPTT) od oko 32°C. S druge strane, nanočestice srebra (AgNPs) poseduju optička, katalitička i električna svojstva koja se mogu modifikovati promenom njihove veličine i oblika a imaju i izražen antibakterijski potencijal, pa su stoga, poslednjih decenija intenzivno proučavane. Pokazano je da se anizotropne nanočestice srebra mogu kontrolisano sintetisati sa fizičkohemijskim svojstvima različitim od sfernih analoga, pri čemu su značajna istraživanja usmerena na njihovu praktičnu primenu. Zbog svega navedenog, u okviru ovog istraživanja biće izvedena jednostavna dvostepena sinteza AgNPs/PNiPAAm hidrogel nanokompozita koja uključuje hemijsko formiranje sfernih i trouglastih AgNPs u prvom koraku, a zatim gama-indukovano umrežavanje NiPAAm-a u prisustvu ovih AgNPs. Tehnika gama zračenja objedinjuje sterilizaciju i sintezu u jednom tehnološkom koraku čime se proces optimizuje i otvara širok spektar inovativnih biomedicinskih primena. Formiranje stabilnih i uniformno distribuiranih AgNPs unutar matrice hidrogela potvrđeno je UV-Vis spektroskopijom, a porozna sunđerasta struktura polimerne mreže SEM analizom. Fizičkohemijska karakterizacija izvršena je i ispitivanjem procesa bubrenja i kontrahovanja u vodi na 25°C i 48°C, redom. Pored toga, pokazano je da prisustvo AgNPs utiče na vrednosti temperature faznog prelaza polimera. Osnovni cilj ovog istraživanja je ispitivanje uticaja različite morfologije AgN

Antioxidants have a significant contribution in the cell protection against free radicals which may induce oxidative stress, and permanently damage the cells causing different disorders such as tumors, degenerative diseases, and accelerated aging. Nowadays, a multi-functionalized heterocyclic framework plays an important role in drug development, and it is of great importance in organic synthesis and medicinal chemistry. Encouraged by the bioactivity of the pyrido-dipyrimidine scaffold and vanillin core, herein, we made an effort to thoroughly investigate the antioxidant potential of the vanillin-based pyrido-dipyrimidines A–E to reveal novel promising free radical inhibitors. The structural analysis and the antioxidant action of the investigated molecules were performed in silico by DFT calculations. Studied compounds were screened for their antioxidant capacity using in vitro ABTS and DPPH assays. All the investigated compounds showed remarkable antioxidant activity, especially derivative A exhibiting inhibition of free radicals at the IC50 value (ABTS and DPPH assay 0.1 mg ml−1 and 0.081 mg ml−1, respectively). Compound A has higher TEAC values implying its stronger antioxidant activity compared to a trolox standard. The applied calculation method and in vitro tests confirmed that compound A has a strong potential against free radicals and may be a novel candidate for application in antioxidant therapy.

Predmetnim pronalaskom postignuta je inkapsulacija slabo vodorastvorne aktivne supstance heterocikličnog azo jedinjenja sa antikancerogenim svojstvima u hidrofilni hidrogel na bazi poli(metakrilne kiseline) modifikovanog amfifilnim kazeinom, ciljana dostava inkapsuliranog azo derivata i njegovo kontrolisano i produženo otpuštanje (i do 72h) bez naglog inicijalnog oslobadanja iz hidrofilnog hidrogela. Takođe, predmetnim pronalaskom su dobijeni nosači koji bi imali potencijalnu primenu u tretmanu hronične mijeloidne leukemije (HML), čijom bi se primenom smanjio broj potrebnih terapeutskih doza i redukovali neželjeni efekti (kao što je povraćanje i iritacija gastrointestinalnog trakta) koji se najčešće javljaju kod primene lekova za terapiju HML.

Chitosan is a natural polymer obtained by deacetylation of chitin. Due to its biocompatibility and biodegradability, chitosan-based materials have a wide range of biomedical applications in wound dressings, drug delivery systems, and tissue engineering. Also, studies in the fields of organic and medicinal chemistry show that compounds based on the pyridone core exhibit biological properties including antimicrobial, anticancer, and antioxidant activity, and moreover have the potential as new therapeutics for various diseases from cardiovascular to antitumor therapy. In this study, new biomaterials were synthesized using low and medium molecular weight chitosan polymers and pyridone-based hydrazone. In order to improve stability of the obtained scaffolds, scaffolds’ neutralization was carried out using ethanol and sodium hydroxide solutions. The interactions established between chitosan polymer chains and pyridone compound were analyzed by FT-IR spectroscopy. Swelling and degradation tests of the materials were studied in water and PBS, and the influence of different polymer molecular weights on the scaffolds’ properties was evaluated. The results indicated that synthetized scaffolds have a high potential for biomedical use.

Researchers are faced with everyday demands for safer and more efficient therapy for many diseases, especially serious one such as various types of cancer. Numerous anticancer drugs are poorly-water soluble and therefore their encapsulation and controlled release remain quite challenge. In present study, we deepened our research of hydrophilic carrier based on poly(methacrylic acid) and casein (PMAC) by investigating its potential for encapsulation and controlled release of novel poorly water-soluble dihydropyrimidion-azo-pyridon compound (DHPMP). DHPMP is a dye that has been proven to show cytotoxic activity against chronic myeloid leukemia K562 cells. By encapsulating DHPMP into the carrier and delivering it into the intestines, DHPMP absorption could be the fastest and the number of therapeutic doses and side effects can be reduced. Carriers based on PMAC and DHPMP (PMAC-DHPMP) were synthetized and characterized by FTIR, SEM and single compression tests. The swelling behavior of PMAC-DHPMP carriers and cumulative DHPMP release were investigated depending on the amount of crosslinker and encapsulated DHPMP in two media which were simulating pH environments in human stomach and intestines. The prolonged and controlled release of DHPMP was achieved. In vitro cytotoxic activity of PMAC-DHPMP carriers against K562 cells and the cell cycle analysis showed great potential of the carriers for application in leukemia treatment.

U ovom radu prikazana je sinteza i karakterizacija 6-hidroksi-4-metil-3-(piridinijum-1-il)-2-piridona. Sintetisano jedinjenje dobijeno je u obliku dipol-jona. Spektrofotometrijskom titracijom u rastvoru etanola ispitan je uticaj pH vrijednosti na strukturu jedinjenja. Kako bi se detaljno opisala struktura derivata 2-piridona, eksperimentalno dobijene vrijednosti dobijenih apsorpcionih maksimuma upoređeni su sa kvantno-hemijskim proračunima optimizovanih geometrija i teorijskih UV-Vis spektara pri različitim pH vrijednostima., In this research, synthesis and characterization of 6-hydroxy-4-methyl-3-(pyridinium-1-yl)-2-pyridone was shown. Synthesized compound was achieved in the zwitterionic form. UV-Vis spectrophotometric titration was performed in order to examine the influence of pH values on the structure of the compound. For the purpose of detail characterization of 2-pyridone derivative, experimentally obtained results were compared to quantum-chemical calculations of optimized geometries and theoretical UV-Vis spectra of solution for different pH values.

Recently, one of the fastest growing areas in materials sciences is the development of polymer-based smart materials, which can autonomously change their physical and/or chemical properties under external stimuli. Among them, photoactuators as smart materials that can produce a reversible mechanical deformation under light stimuli have attracted tremendous interest due to their potential applications in soft robotics, artificial muscles, and smart devices. Currently, the fabrication of photoactuators is mainly based on photothermal actuation mechanisms which include expansion/contraction, molecule sorption/desorption, and phase transition. Thermosensitive hydrogels with gold nanoparticles are probably the most commonly used active layers. The functional gold nanoparticles exhibit unique photo-thermal properties as a result of a surface plasmon resonance (SPR) electron-phonon process and intrinsic inter-band transitions. Upon immobilization in thermoresponsive hydrogel, they induce local photo-thermal shrinking under visible light irradiation and thus enable external wireless remote control of hydrogel device and programmable photo-thermomechanical motions such as bending, curling, and spiralling. In this work, bi-layered photoactuators based on thermosensitive poly(N-isopropylacrylamide) (PNiPAAm) hydrogel with incorporated gold nanoparticles as an active layer, and poly(vinyl alcohol) hydrogel as a passive layer were produced. Crosslinking of polymer matrix was done by combination of freeze-thaw and radiolytic methods, while nanoparticles were synthesized using the seed-mediated approach. Two different shapes of nanoparticles were incorporated into PNiPAAm hydrogel, gold nanospheres (AuNPs) with radius around 10 nm and gold nanorods (AuNRs) with aspect ratio of 5 (radius of 10 nm, length of 50 nm). The formation of nanoparticles within the active layer was confirmed by appearance of characteristic SPR bands with maxima around 540 nm for AuNPs, and transversal oscil

In this study, bi-layered hydrogel nanocomposites, based on gold nanoparticles (AuNPs) embedded in poly(N-isopropylacrylamide) (PNiPAAm) and poly(vinyl alcohol) (PVA) hydrogel were developed. PNiPAAm with AuNPs represents an active, while PVA represents a passive layer. Crosslinking of polymer matrix with stable 3D structure was obtained by the combination of freezethaw and radiolytic methods, while nanoparticles were synthesized using the seed-mediated approach. The UV-Vis absorption spectra and TEM measurements confirm the presence of spherical AuNPs, with a diameter of 30 nm. The influence of AuNPs on the swelling/deswelling behavior and on volume phase transition temperature (VPTT) in distilled water was investigated. The obtained results showed that values of network and diffusion parameters increase with the incorporation of AuNPs and that the swelling transport mechanism is a non-Fickian transport.

The heterocyclic azo dyes represent significant synthetic organic colorants. In addition to their exceptional coloration properties, heterocyclic azo compounds exhibit antibacterial, antifungal, an-tiviral, antioxidant, anti-inflammatory and anticancer properties. The antimicrobial resistance is one of the major problems for global public health. Therefore, finding new organic structures with anti-microbial properties represents a challenging research field. In this study, antimicrobial screening of two Biginelli-based azo pyridone dyes has been carried out. The antimicrobial activity of synthe-tized dyes wasstudied against bacteria (Staphylococcus aureus, Escherichia coli) and yeast (Candida albicans), using agar diffusion method. The preliminary research results indicate the antimicrobial potential of the investigated compounds., Heterociklična azo jedinjenja predstavljaju značajnu klasnu organskih sintetskih boja. Pored njihovih izuzetnih svojstava za bojenje, heterociklična azo jedinjenja imaju i biološku aktivnost. Mnoge studije pokazuju da azo boje sa heterocikličnim fragmentima u strukturi mogu ispoljavati antibakterijska, antifungalna, antivirusna, antiinflamatorna i antikancerogena svojstva. Rezistencija mikroorganizama na postojeće antimikrobne agense predstavlja jedan od najvećih problema u svetskom zdravstvu. Zbog toga je razvijanje novih molekula sa antimikrobnim svojstvima kako značajno, tako i neophodno za globalno očuvanje zdravlja. U ovom radu, ispitivanje antimikrobne aktivnosti dve Biđineli-azo piridonske boje je urađeno pomoću metode difuzije na agarnoj podlozi. Antimikrobna svojstva su ispitana prema patogenim sojevima Staphylococcus aureus (Gram-pozitivna bakterija), Escherichia coli (Gram-negativna bakterija) i Candida albicans (oportunistički kvasac). Preliminarni rezultati istraživanja ukazali su na antimikrobni potencijal ispitivanih azo jedinjenja.

Heterociklična azo jedinjenja predstavljaju značajnu klasnu organskih sintetskih boja. Pored njihovih izuzetnih svojstava za bojenje, heterociklična azo jedinjenja imaju i biološku aktivnost. Mnoge studije pokazuju da azo boje sa heterocikličnim fragmentima u strukturi mogu ispoljavati antibakterijska, antifungalna, antivirusna, antiinflamatorna i antikancerogena svojstva. Rezistencija mikroorganizama na postojeće antimikrobne agense predstavlja jedan odnajvećih problema u svet-skom zdravstvu. Zbog toga je razvijanje novih molekula sa antimikrobnim svojstvima kako značajno, tako i neophodno za globalno očuvanje zdravlja. U ovom radu, ispitivanje antimikrobne aktivnosti dve Biđineli-azo piridonske boje je urađeno pomoću metode difuzije na agarnoj podlozi. Anti-mikrobna svojstva su ispitana prema patogenim sojevima Staphylococcus aureus (Gram-pozitivna bakterija), Escherichia coli (Gram-negativna bakterija) i Candida albicans (oportunistički kvasac). Preliminarni rezultati istraživanja ukazali su na antimikrobni potencijal ispitivanih azo jedinjenja., The heterocyclic azo dyes represent significant synthetic organic colorants. In addition to their exceptional coloration properties, heterocyclic azo compounds exhibit antibacterial, antifungal, an-tiviral, antioxidant, anti-inflammatory and anticancer properties. The antimicrobial resistance is one of the major problems for global public health. Therefore, finding new organic structures with anti-microbial properties represents a challenging research field. In this study, antimicrobial screening of two Biginelli-based azo pyridone dyes has been carried out. The antimicrobial activity of synthe-tized dyes wasstudied against bacteria (Staphylococcus aureus, Escherichia coli) and yeast (Candida albicans), using agar diffusion method. The preliminary research results indicate the antimicrobial potential of the investigated compounds

Schiff bases, or azomethine compounds, are commonly employed in the fields of organic synthesis, metal complexes, materials, and engineering. Especially, they have gained importance in medicinal researches, considering their antimicrobial, anticancer, antiinflammatory, and antioxidant properties. On the other side, azo dyes are the most significant group of synthetic dyes, utilized in textile fiber dyeing. Conjugation of Schiff bases with azo compounds leads to the class of azo-azomethine dyes, which have numerous applications related to their coloration and biological properties. Viscose is a textile material widely used in the medicine. Moreover, viscose fiber can be engineered in many ways which are significant in the development of medical materials. The antioxidant effect is an important feature of medical textiles, such as wound dressings. In this work, the microwave-assisted synthesis and characterization of novel azo-azomethine dye are reported. The azo-azomethine dye is obtained by the condensation between arylazo pyridone dye and 4-aminophenol. The structure of synthesized dye was determined by ATR-FTIR, NMR, and UV-Vis spectroscopy. Azoazomethine dye was used for dyeing viscose, and the washing fastness of dyed material was evaluated according to the standard method. The viscose fabrics, before and after washing, were analyzed in terms of their color coordinates in the CIELab color space. The antioxidant properties of azo-azomethine dye and dyed viscose fabrics were examined by the ABTS method.

Seven novel azo dyes with 2-pyridone and dihydropyrimidinone moieties have been synthesized and thoroughly characterized. The azo-hydrazone tautomerism has been investigated by experimental and theoretical approaches. The optimizations of geometries have been performed with density functional theory (DFT). The vibrational and NMR spectra were calculated and correlated with experimental ones. Furthermore, quantum chemical descriptors were calculated and MEP maps were plotted to determine biological reactivity of dyes. The antioxidant assay evinced that 5, 6 and 7 are promising antioxidant candidates. In vitro cytotoxic activity was studied against three malignant cell lines: prostate adenocarcinoma (PC-3), lung carcinoma (A549) and chronic myelogenous leukemia (K562), as well as against human normal lung fibroblasts (MRC-5), using MTT assay. Examination of cytotoxic effects on human cancer cell lines showed the concentration dependent cytotoxicity of all investigated compounds. The K562 cells were the most sensitive to the cytotoxicity of the compounds 3, 5 and 6, wherein compound 5 was particularly prominent and selective in cytotoxic action between K562 (24.97 mu M) and PC-3 (48.98 mu M) cancer cells, and normal MRC-5 (91.11 mu M) cells. Moreover, the cell cycle analysis of compound 5 was examined in K562 cells, by flow cytometry, to study its mechanism of anticancer action. Finally, in silico evaluation of physicochemical parameters, druglikeness and ADME properties showed that investigated compounds are orally bioavailable with no permeation to the blood brain barrier.

In recent years, the growing interest in the synthesis of heterocyclic azo dyes can be assigned to a versatile application and biological activities such as antibacterial, antifungal, antioxidant, analgesic, antitubercular and anticancer, of these compounds. Azo dyes based on 2-pyridone core are important since they manifest a variety of biological properties, including potency for the cancer therapy. Moreover, DHPM (3,4-dihydropyrimidin-2(1H)-on) scaffold displays a wide range of biological activities, which has led to the development of numerous drug candidates, based on this structure. Since the cancer is one of the main targets in therapeutic chemistry, we have made an effort to design azo molecules with potential anticancer activity. In this direction, we have synthesized DHPM scaffold suitable for diazo coupling reaction with different 2-pyridones, in order to design a novel series of azo pyridone molecules. The chemical structures of obtained dyes have been confirmed by ATR-FTIR, NMR, UV-Vis, MS and elemental analysis. The antioxidant activity has been evaluated by ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) assay. In vitro antitumor action of DHPM precursor and related azo dyes was determined against prostate adenocarcinoma (PC-3), lung carcinoma (A549) and chronic myelogenous leukemia (K562) tumor cell lines, as well as against human normal lung fibroblast (MRC-5), using MTT (microculture tetrazolium test) assay. The physicochemical parameters, druglikeness and ADME properties of novel compounds were evaluated in silico by SwissADME. The ATR-FTIR and NMR spectroscopy confirmed that obtained dyes exist in hydrazone tautomeric form. The antioxidant assay evinced that three members of this dyes’ series are promising antioxidant candidates. Examination of cytotoxic effects on human cancer cell lines showed the concentration dependent cytotoxicity of all investigated compounds. It has been noted that cytotoxic activity of investigated dyes depe

Azo dyes are the most important group of organic synthetic dyes. High molar extinction coefficients, which characterize azo compounds, contribute to their wide use in traditional dyeing of various materials, as well as the increasing application in new technologies such as optical devices and solar cells. Numerous studies show that azo dyes based on heterocyclic molecules possess biological activity. Arylazo pyridone dyes belong to the class of disperse dyes, which exhibit antibacterial, antifungal, anticancer and antioxidant properties. In this work, three azo dyes were synthesized starting from 2-, 3- and 4-aminophenol and 3-cyano-6-hydroxy-4-methyl-1-propyl-2-pyridone. The structure of dyes was confirmed by ATR-FTIR, NMR and UV-Vis spectroscopy. The antioxidant activity of compounds was examined by the ABTS method. Physico-chemical descriptors and ADME parameters were determined in silico using SwissADME program., Azo boje su najznačajnija grupa organskih sintetskih boja. Visoki molarni ekstencioni koefici-jenti, koji karakterišu azo jedinjena, doprinose njihovoj širokoj upotrebi kako u tradicionalnom bo-jenju materijala, tako i sve većoj primeni u novijim tehnologijama kao što su optički materijali i solarne ćelije. Mnoga istraživanja pokazuju da azo boje dobijene iz heterocikličnih molekula imaju biološku aktivnost. Arilazo piridonske boje pripadaju klasi disperznih boja koje ispoljavaju antibak-terijsku, antifungalnu, antikancerogenu i antioksidativnu aktivnost. U ovom radu sintetisane su tri azo boje polazeći iz 2-, 3-i 4-aminofenola i 3-cijano-6-hidroksi-4-metil-1-propil-2-piridona. Struk-tura jedinjenja potvrđena je ATR-FTIR, NMR i UV-Vis podacima. Antioksidsativna aktivnost jedinje-nja ispitana je ABTS metodom. Fizičko-hemijski deskriptori i ADME parametari određeni su in silico pomoću SwissADME programa.

Budući da tekstilna industrija predstavlja jednu od glavnih grana industrije, razvoj globalne ekonomije je direktno povezan sa razvojem tekstilne industrije. Sa druge strane, razvoj novih boja je od ključnog značaja za samu tekstilnu industriju. Boje predstavljaju jednu od glavnih zagađujućih materija u otpadnim vodama što predstavlja ekološki problem. Azo boje se nerijetko koriste u industriji kao jedna od najvećih grupa sintetskih boja. Piridinski prsten pokazuje odlično vezivanje za vunu, dok sa druge strane hromofore azo boja daju odlično obojenje. U ovom radu, dvije boje su korišćene za bojenje vune, pri čemu je isti rastvor za bojenje korišćen više puta. Cilj ovog rada je da se smanji udio boja u otpadnoj vodi. Količina boje koja se vezela za vunu, tj. koja je ostala u rastvoru, praćena je UV-Vis spektroskopijom., Considering that the textile industry is an evergrowing industry and its growth directly contributes to economic growth, the interest in developement is strongly dependent with developing new colorants. On the other hand, colored effluent from the textile industry cause water pollution which has an acute effect on the enviorment. The reduction of dye waste and toxicity represents a global problem. As state-of-the art showed pyridine ring allows excellent sublimation fastness for dying wool fibers, wherein azo dyes show brilliant chromophoric strength. Herein, we present the wool dyed with two pyridone based azo dyes bearing pyridinium ring as a substituent. The aim of this work is to reduce the water waste by using the same dyebath for dying wool multiple times. The amount of the dye absorbed on the fabric is determined by the absorption spectra of the dye solution used in the dyebath, followed by the UV-Vis spectra. Therefore the principle of reusing the same dyebath multiple times were determined, wherein the concentration of the dye in the final product is reduced.

U ovom radu prikazane su sinteza i primena dve azo boje na bazi 6-hidroksi-4-metil-3-piridinijum2-piridona. Supstituisani piridon dobijen je Guareši-Torpeovom reakcijom kondenzacije, dok su azo boje sintetisane klasičnim postupkom diazo kuplovanja pri čemu su korišćena dva različito supstituisana anilina. Primenom FTIR, 1H i 13C NMR, UV-Vis i masene spektroskopije dobijena jedinjenja su okarakterisana. U zavisnosti od rastvarača i supstituenta, boje se nalaze u ravnoteži dva tautomerna oblika, hidrazonskog i cviterjonskog, za razliku od literaturnih analoga u kojima se navodi hidrazon-azo anjon ravnoteža. Specifična struktura dobijenih boja omogućava bolju rastvorljivost, pre svega u vodi. Primena se sastoji u bojenju vune pri ranije optimizovanim uslovima bojenja. U ovom radu na osnovu predloženog mehanizma vidi se da, pored očekivanih vodoničnih veza, jon-jon interakcije učestvuju u vezivanju boje za tkaninu. Komparativna studija antioksidativne aktivnosti boja i obojenih tkanina urađena je pomoću ABTS metode., Herein, we report the synthesis and application of two azo dyes based on 6-hydroxy-4-methyl-3- pyridinium-2-pyridone. The substituted pyridone was synthesized via Guareschi-Thorpe condensation, wherein dyes are obtained by the classical reaction of diazo coupling by using two diversely p-substituted anilines. The characterization of the synthesized compounds was carried out by FTIR, 1H and 13C NMR, UV-Vis and mass spectroscopy. These compounds exist in an equilibrium of two tautomeric forms in solution depending on the solvent as well as on the substituent and are water-soluble. It is worth mentioning that the hydrazone form of the dyes is in equilibrium with the zwitterion form of the dyes unlike the literature analogs existing in the anionic form. The application of the dyes consists of dying wool fiber at optimized conditions. The dying mechanism is suggested, wherein it revealed that these like dyes utilize ion-ion interactions next to expected hydrogen bonds. A comparative study on the antioxidant activity of the dyes and the dyestuff was conducted using ABTS assay.

A carbon-rich product, hydrochar, was synthesized by hydrothermal carbonization (HTC) of spent mushroom substrate (SMS), at temperature of 260 °C. The thermal kinetic analysis has shown that hydrothermally treatment improve the combustion behavior of hydrochar. The kinetic parameters were determined by Kissinger and Ozawa methods. The SMS-260 had a significantly lower activation energy compared to the SMS, which means that this hydrochar needs a smaller amount of energy to start combustion. Generally, the preliminary results show that HTC is an effective way to transform SMS into alternative solid biofuel.

Nowadays, humanity are faced with many challenges which affect health of people all aroundthe globe (such as climate change, new diseases and/or already present ones for which cure hasnot been found yet – cancer). The efforts of researchers on the field of drug delivery systemsbring everyday novel tools for safer and more effective therapy. pH sensitive hydrogels basedon poly(methacrylic acid) are recognized as materials with huge potential for controlled releaseof drugs. The encapsulation and controlled release of many chemotherapeutics is quitechallenge due to their poorly water-solubility. In our previous research we overcome thisproblem by modifying hydrophilic pol(methacrylic acid) with amphiphilic casein and showedthat prepared material have potential for encapsulation and controlled release of poorly watersoluble model drug – caffeine (PMAC carriers). In present study we deepened further ourresearch and employed various models: Ritger-Peppas, Higuchi and Kopcha model to analyzehow the change of crosslinker amount affect the mechanism of release kinetics of caffeine inmedium with pH of 6.8 (which simulated the environment in human intestines). Obtainedresults showed that only by changing one parameter such as crosslinker amount it is possible tofine tune the type of drug release mechanism, due to which the PMAC carriers would be ableto respond to the specific demands of therapy.

A new heterocyclic azo dye 5-(2,6-dimethylphenyl)-6-hydroxy-4-methyl-2-oxo-1,2- dihydropyridine-3-carboxamide was synthesized and structurally characterized by elemental analysis, FTIR, 1H and 13C NMR spectroscopy techniques. These analysis have confirmed that synthesized dye exists in the tinctorial strongest tautomeric form, hydrazone form. The dye is characterized by reflection spectrum, while absorption and emisson spectra are recorded in nine different solvents. The antioxidant activity of the synthesized dye has been chemically tested and has been shown to have great potential as an antioxidant molecule.

Removal of heavy metals is important because of their toxic effects on living organisms and unwanted anthropogenic effects. Biochar is suitable as an adsorbent of heavy metals due to its advantages such as various sources of biomass, a large number of microporous channels and surface functional groups, as well as due to its economic viability. There is no data about the plum pomace biochar usage as adsorbent for lead removal. In this study, the plum pomace biochar modified with gamma irradiation (IrPP) is used for the removal of Pb2+ ions from the aqueous solution. The SEM micrographs revealed that surface morphology of plum pomace is suitable for metal adsorption. The results of adsorption kinetics demonstrated that the removal process of Pb2+ ions onto IrPP follows a pseudo-second kinetic model, which is confirmed by a better agreement between qe,cal=227 mg g–1 and qe,exp=224 mg g–1. Therefore, based on preliminary research, it can be concluded that IrPP originating from biowaste is a promising, eco-friendly sorbent of heavy metal from wastewater.

Molecular imaging is a relatively new research field, which has demonstrated great potential, especially in clinical oncology – from drug development to cancer early detection. The key of fluorescence imaging is the construction of fluorescent probe which is composed of two parts, the recognition groups to recognize cancer cells, and fluorophores to signal the recognition events. In this research, the structure of new fluorescent azo dye based on 2-oxo-1,2,3,4-tetrahydropyrimidin and 2-pyridone moieties has been reported. The absorption and emission properties of the investigated azo dye have been studied using UV-Vis and fluorescence spectroscopy. The obtained results suggest that studied dye meets the requirements for new green-emitting fluorescent probe, suitable for further application in biomedical researches.

Targeted drug delivery is powerful tool which researchers use to achieve safer and more efficienttherapy of many diseases, including various types of cancer. Many chemotherapeutics are poorly watersoluble, so their encapsulation and targeted delivery remain quite challenge. Hydrogels based onpoly(methacrylic acid) (PMAA) are widely investigated for targeted drug delivery due to their pHsensitivity, non-toxicity and biocompatibility. Still, due to the PMAA highly hydrophilic nature, PMAAcan only be used for encapsulation and targeted delivery of water-soluble drugs. Our previous researchwas directed towards overcoming this limitation: PMAA was modified with amphiphilic protein –casein and poorly-water soluble model drug – caffeine – was encapsulated (PMAC). Present study isfocused on investigation how variation of amount of one of the most important hydrogels networkparameter such as crosslinker affect PMAC swelling properties and caffeine release. The group ofhybrid hydrogels – PMAC – was synthesized with various amount of crosslinker: 0.4mol%, 0.8mol%,1.6mol% and 3.2mol% with respect to methacrylic acid. Swelling behavior of hybrid hydrogels andcaffeine release was investigated in two environments which simulated human stomach and intestines.Obtained results showed that targeted delivery of poorly water-soluble model drug was achieved andthat its release can be prolonged up to 24h. Also, kinetic of poorly water-soluble drug release can beeasily modified only by changing crosslinker amount. PMAC hybrid hydrogels have huge potential fortargeted delivery of poorly water-soluble active substances.

Schiff bases, or azomethine compounds, are commonly employed in the fields of organic synthesis, metal complexes, materials, and engineering. Especially, they have gained importance in medicinal researches, considering their antimicrobial, anticancer, antiinflammatory, and antioxidant properties. On the other side, azo dyes are the most significant group of synthetic dyes, utilized in textile fiber dyeing. Conjugation of Schiff bases with azo compounds leads to the class of azo-azomethine dyes, which have numerous applications related to their coloration and biological properties. Viscose is a textile material widely used in the medicine. Moreover, viscose fiber can be engineered in many ways which are significant in the development of medical materials. The antioxidant effect is an important feature of medical textiles, such as wound dressings. In this work, the microwave-assisted synthesis and characterization of novel azo-azomethine dye are reported. The azo-azomethine dye is obtained by the condensation between arylazo pyridone dye and 4-aminophenol. The structure of synthesized dye was determined by ATR-FTIR, NMR, and UV-Vis spectroscopy. Azoazomethine dye was used for dyeing viscose, and the washing fastness of dyed material was evaluated according to the standard method. The viscose fabrics, before and after washing, were analyzed in terms of their color coordinates in the CIELab color space. The antioxidant properties of azo-azomethine dye and dyed viscose fabrics were examined by the ABTS method.

Dyes bearing imino group along with azo one in the structure, present the class of azo-azomethine dyes. Azomethine compounds, known as Schiff bases, find application in biomedical research considering their potential antibacterial, antifungal, antimalaric, anticancer, antiinflammatory and antiviral activity. Furthermore, azo dyes are used in textile fiber dyeing, ink-jet and laser printers, LCDs, photovoltaic devices and metal complexes. With respects to the strong biological activity and a broad spectrum of potential application in industry, herein the microwave assisted synthesis and characterization of three new azo-azomethine dyes is presented. New azo-azomethine dyes were obtained by merging arylazo pyridone dye with different aniline cores resulting in azo-azomethine structure. In addition, tautomerism and solvatochromic properties of the dyes have been discussed., Organske sintetske boje koje u svojoj strukturi sadrže azo i imino grupu predstavljaju klasu azo-azometinskih jedinjenja. Azometinska jedinjenja, poznata kao Schiff-ove baze, imaju značajnu ulogu u biomedicinskim istraživanjima zbog potencijalne antibakterijske, antifungalne, antimalarijske, antikancerogene, antiinflamatorne i antivirusne aktivnosti. Azo-azometinske boje se mogu koristiti u industriji za bojenje tekstilnih vlakana, zatim u LCD ekranima, ink-džet i laserskim štampačima, fotonaponskim uređajima i metalnim kompleksima. U ovom radu prikazana je mikrotalasna sinteza i strukturna karakterizacija tri nove azo-azometinske boje, polazeći iz arilazo piridonske boje i različito supstituisanih anilina. Solvatohromna svojstva i tautomerija novih azo-azometinskih jedinjenja proučavani su u rastvaračima različitih svojstava.

In this study, six 6- and 1,6-substituted-3-cyano-4-methyl-2-pyridones were synthesized in a continuous flow microreactor system. The syntheses were realized at room temperature and the obtained results were compared to those achieved within classical syntheses. In order to optimize the continuous flow syntheses and increase the yield of the products, the retention time in the microreactor was varied by changing the flow rates of the reactant solutions. Furthermore, the reaction was optimized for 3-cyano-4,6-dimethyl-2-pyridone and 3-cyano-6-hydroxy-4-methyl-2-pyridone, which are comercially important in the pharmaceutical and dye industries. Both 2-pyridones were obtained in satisfactory yield of circa 60 % in less than 10 min. The resulting compounds were characterized by their melting points, FT-IR, H-1-NMR and UV-Vis spectra. The efficiency of the presented method for the synthesis of 2-pyridone-based molecules has promising potential for industrial production.

Aromatic heterocyclic compounds containing nitrogen in their structure have attracted considerable interest in medicine, because of their certain pharmacological properties including anticancer, anti-inflammatory, antihypertensive, antibacterial, antifungal and antiviral activities. Among them, derivatives with 2-pyridone moiety are particularly notable due to their wide application in pharmacological and dye industry. A usual procedure for synthesis of 2-pyridone moiety is classic condensation reaction of 1,3- dicarbonyl compounds with cyanoacetamide. However, in the case of various substituted reactants, drawback of this reaction can be a low yield of desirable products and long reaction time. This factor has led to the development of different methods for synthesis in order to overcome these defects. The microreactor technology and flow chemistry could play a significant role in the improving of organic synthesis efficiency. The microreactor approach could provide enhanced productivity, fast conversion and altogether less hazardous chemical synthesis. Furthermore, it pushes towards designing of chemistry with a lower environmental and economic impact. In this study the synthesis of 2-pyridone moiety in a continuous flow coil-type microreactor system was examined. In order to optimize reaction conditions, flow rates of starting reagents were varied. The desirable 2-pyridone was obtained in satisfactory yield of circa 60% in less than 10 minutes. The structure and purity of synthetized 2-pyridone moiety were confirmed by melting point, FT-IR, 1 H NMR and UV-Vis spectra. The efficiency of the presented method for the synthesis of 2-pyridone based molecules has promising scaleup potential.

In the industry, wastewater is important environmental problem. Due to the growing environmental concern this problem became one of key issues. Large amounts of highly contaminated wastewater, as consequence of industrial use, are important environmental polluters. Before discharging, wastewater has to be treated to achieve quality prescribed by law. One of solutions could be decomposition of pollutants. The decomposition of pollutants from industrial wastewaters is of critical importance in order to maintain a clean environment. Many process commonly used in polluter degradation processes commonly use different harmful chemicals or leads to formation of potentially harmful byproducts. Treatment of wastewater from industry in microreactor system is new ecological solution. Over the last few decades microreactors have been increasingly recognized as being an alternative to conventional batch reactors in chemical industry. Application of these systems have aim to transform conventional into more productive and environmental friendlier process. They are characterized by micrometer dimensions and continuous mode, resulting in significant intensification of the mass and heat transfer. Microreactor systems are already find application in chemical industry, biotechnology, pharmaceutical industry and medicine. Decomposition of pollutants in wastewater is complex, but microreactors allow purification with low quantities of chemical reagents. This paper represents review of possible fields of wastewater purification – waste material decomposition in microreactor systems.

Wastewater treatment is one of the most analysed issue in theory and practice because of its current and vast significance nowadays. Wide range of chemical, physical and biochemical processes are developed for wastewater treatment. Although biochemical processes are the most eco-friendly when compared to chemical and physical, they are still not the leading type of technology in this field. In recent years, microreactors are trending because of their particular characteristics that can be utilized in numerous areas. Continuous flow, higher reaction yields, scale independant and high selectivity are just a few of the beneficial characteristics of microreactors. Due to the micro channels, turbulent flow regime is avoided. Furthermore, high surface-to-area ratios aid in far greater and faster heat and mass transfer than in common reactors. Another asset of microreactors is short diffusion pathways, that together with small reaction pathways add to its favorable attributes. When it comes to enzymes, due to their small size and mild reaction conditions requirements, they are ideal for working in microreactos. Enzymes can be isolated from different sources, but isolation from plant waste material is what makes them even more interesting. Because of the above mentioned microreactor’s pros, several enzyme’s disadvantagious properties are overcome. In this study, a review of the positive characteristic of enzyme microreators in wastwater treatment will be discussed.

In this study, six 6- and 1,6-substituted-3-cyano-4-methyl-2-pyridones were synthesized in a continuous flow microreactor system. The syntheses were realized at room temperature and the obtained results were compared to those achieved within classical syntheses. In order to optimize the continuous flow syntheses and increase the yield of the products, the retention time in the microreactor was varied by changing the flow rates of the reactant solutions. Furthermore, the reaction was optimized for 3-cyano-4,6-dimethyl-2-pyridone and 3-cyano-6-hydroxy-4-methyl-2-pyridone, which are comercially important in the pharmaceutical and dye industries. Both 2-pyridones were obtained in satisfactory yield of circa 60 % in less than 10 min. The resulting compounds were characterized by their melting points, FT-IR, H-1-NMR and UV-Vis spectra. The efficiency of the presented method for the synthesis of 2-pyridone-based molecules has promising potential for industrial production.

Local structural and electronic properties around Fe in multi-component Cd0.99Fe0.01Te0.97S0.03 system were studied by means of X-ray absorption fine structure (XAFS). Composition of non-polar (110) surfaces of Cd0.97Fe0.03Te and Cd0.99Fe0.01Te0.97S0.03 systems and mechanism of their oxidation in ambient conditions were studied by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). It has been found that Fe preferentially substitutes Cd, but due to much smaller covalent radius and preferences for paring with S, it causes local distortion of the host CdTe lattice. The distortion is confined to the Fe-immediate surrounding and the second and third coordination shell atoms are (inside experimental uncertainties) placed at distances expected in CdTe. Although local structure around Fe is well defined in the bulk of both samples, their near-surface region is completely depleted from Fe, and in case of Cd0.99Fe0.01Te0.97S0.03 somewhat enriched in S. Special attention is, therefore, paid to characterization of the near-surface region and evaluation of its composition and structure. To that end we have introduced a general standard-free algorithm for XPS data analysis of the two-layer surface structure (bulk, oxide layer, and the impurity layer). Results of the in-depth composition analysis revealed that despite different bulk composition and impurity layer thickness, underneath the topmost impurity layer lays approximately one monolayer of CdTeO3 which passivates the surface. © 2018 Elsevier B.V.