Synthesis of novel coumarin derivatives by using Pd-catalysed reactions and their structural characterization

U ovom radu opisana je sinteza derivata 7-hidroksikumarina pripravljenih reakcijom bromiranja, nitriranja, te paladijem kataliziranim reakcijama. Bromiranjem 7-hidroksikumarina s N-bromsukcinimidom uz cerijev amonijev nitrat pripravljeni su 8-brom-7-hidroksikumarin (1) i 3,8-dibrom-7-hidroksikumarin (2). Reakcijom nitriranja 7-hidroksikumarina sintetizirani su derivati kumarina supstituirani nitro skupinom u položajima 3 i/ili 6 i 8 kumarinskog prstena (3-5). 7-hidroksi-4-(3-(p-tolil)prop-2-in-1-il)kumarin (6) supstituiran u položaju C-4 pripravljen je Sonogashira-inom reakcijom unakrsnog povezivanja 7-hidroksi-4-klormetilkumarina s 4-metilfenilacetilenom uz Pd-katalizator. Suzuki-jevom reakcijom 7-hidroksi-4-klormetilkumarina s (4-hidroksifenil)bornom kiselinom uz Pd-katalizator sintetiziran je 7-hidroksi-4-(4-hidroksibenzil)kumarin (7). Strukture sintetiziranih spojeva 1-7 potvrđene su 1H NMR spektroskopijom. Derivati kumarina 1-3 spektroskopski su okarakterizirani UV/Vis i fluorimetrijskom spektroskopijom, te su im određeni maksimumi apsorbancije i valne duljine emisije.This work describes the synthesis of 7-hydroxycoumarin derivatives prepared by the bromination, nitration and palladium-catalyzed reactions. 8-bromo-7-hydroxycoumarin (1) and 3,8-dibromo-7-hydroxycoumarin (2) were prepared by the bromination of 7-hydroxycoumarin with N-bromosuccinimide and ceric ammonium nitrate. Coumarin derivates with nitro group substituted at the positions 3 and/ or 6 and 8 of coumarin ring (3-5) were synthesized by the nitration of 7-hydroxycoumarin. 7-hydroxy-4-(3-(p-tolyl)-2-yn-1-yl)-2H-chromen-2-one (6) substituted at C-4 was prepared by Sonogashira cross-coupling reaction of 4-(chloromethyl)-7-hydroxycoumarin and 2-(p-tolyl)ethyn-1-ylium with Pd-catalyst. 7-hydroxy-4-(4-hydroxybenzyl)-2H-chromen-2-one (7) was synthesized by Suzuki reaction of 4-(chloromethyl)-7-hydroxycoumarin and (4-hydroxyphenyl)boronic acid using Pd-catalyst. The structures of the synthesized compounds 1-7 were confirmed by 1H NMR spectroscopy. Coumarin derivates 1-3 were spectroscopically characterized by UV/ Vis and fluorimetric spectroscopy and their maxima of absorbance and emission wavelengths were determined

Synthesis of novel coumarin derivatives by using Pd-catalysed reactions and their structural characterization

U ovom radu opisana je sinteza derivata 7-hidroksikumarina pripravljenih reakcijom bromiranja, nitriranja, te paladijem kataliziranim reakcijama. Bromiranjem 7-hidroksikumarina s N-bromsukcinimidom uz cerijev amonijev nitrat pripravljeni su 8-brom-7-hidroksikumarin (1) i 3,8-dibrom-7-hidroksikumarin (2). Reakcijom nitriranja 7-hidroksikumarina sintetizirani su derivati kumarina supstituirani nitro skupinom u položajima 3 i/ili 6 i 8 kumarinskog prstena (3-5). 7-hidroksi-4-(3-(p-tolil)prop-2-in-1-il)kumarin (6) supstituiran u položaju C-4 pripravljen je Sonogashira-inom reakcijom unakrsnog povezivanja 7-hidroksi-4-klormetilkumarina s 4-metilfenilacetilenom uz Pd-katalizator. Suzuki-jevom reakcijom 7-hidroksi-4-klormetilkumarina s (4-hidroksifenil)bornom kiselinom uz Pd-katalizator sintetiziran je 7-hidroksi-4-(4-hidroksibenzil)kumarin (7). Strukture sintetiziranih spojeva 1-7 potvrđene su 1H NMR spektroskopijom. Derivati kumarina 1-3 spektroskopski su okarakterizirani UV/Vis i fluorimetrijskom spektroskopijom, te su im određeni maksimumi apsorbancije i valne duljine emisije.This work describes the synthesis of 7-hydroxycoumarin derivatives prepared by the bromination, nitration and palladium-catalyzed reactions. 8-bromo-7-hydroxycoumarin (1) and 3,8-dibromo-7-hydroxycoumarin (2) were prepared by the bromination of 7-hydroxycoumarin with N-bromosuccinimide and ceric ammonium nitrate. Coumarin derivates with nitro group substituted at the positions 3 and/ or 6 and 8 of coumarin ring (3-5) were synthesized by the nitration of 7-hydroxycoumarin. 7-hydroxy-4-(3-(p-tolyl)-2-yn-1-yl)-2H-chromen-2-one (6) substituted at C-4 was prepared by Sonogashira cross-coupling reaction of 4-(chloromethyl)-7-hydroxycoumarin and 2-(p-tolyl)ethyn-1-ylium with Pd-catalyst. 7-hydroxy-4-(4-hydroxybenzyl)-2H-chromen-2-one (7) was synthesized by Suzuki reaction of 4-(chloromethyl)-7-hydroxycoumarin and (4-hydroxyphenyl)boronic acid using Pd-catalyst. The structures of the synthesized compounds 1-7 were confirmed by 1H NMR spectroscopy. Coumarin derivates 1-3 were spectroscopically characterized by UV/ Vis and fluorimetric spectroscopy and their maxima of absorbance and emission wavelengths were determined

Usporedba masenih koncentracija PAU-a u lebdećim česticama zraka priobalnog područja srednjeg Jadrana i središnje Hrvatske

Polycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants due to their distribution, persistence, bioaccumulation, and adverse effects on human health. The aim of this study was to obtain the first insight into PAHs mass concentrations bound to airborne particulate matter (PM) in the mid Adriatic coast area of Croatia, and compare them with the PAH levels in Croatia’s urban central area. Relatively low values of PAH mass concentrations were measured in the coastal area, compared to the continental urban region of Croatia impacted by increased emissions due to intensive traffic, industry, and residential heating. A high PM10 contribution of four-ring PAHs (Flu and Pyr) at Martinska site indicated that wood burning heating as well as open fire events, including waste incineration, could be important emission sources of PAHs in the mid Adriatic coast region. This work is licensed under a Creative Commons Attribution 4.0 International License.Policiklički aromatski ugljikovodici (PAU) zbog rasprostranjenosti, postojanosti, bioakumulacije i štetnih utjecaja na zdravlje ljudi te biljnog i životinjskog svijeta smatraju se prioritetnim onečišćujućim tvarima. Cilj istraživanja je po prvi put dobiti uvid u masene koncentracije specifičnih PAU-a u lebdećim česticama u zraku priobalnog područja srednjeg Jadrana te napraviti usporedbu s razinama PAU-a urbanog područja središnje Hrvatske. Koncentracije PAU-a u priobalnom području bile su relativno niske u odnosu na koncentracije u urbanoj središnjoj Hrvatskoj, gdje se i očekuju njihove povišene emisije uslijed znatno jačeg intenziteta prometa, industrije te izgaranja biomase uslijed loženja u kućanstvima. Veća zastupljenost PAU-a četirima aromatskim prstenovima (Flu i Pyr) u ukupnoj masi PM10 čestica na mjernoj postaji Martinska upućuju na to da izgaranje drvne biomase uslijed grijanja kućanstava te uslijed požara otvorenog tipa mogu biti važan izvor PAU-a na obalnom dijelu srednjeg Jadrana. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Cystic Fibrosis – results of CFTR modulators in Croatia

Cistična fibroza najčešća je nasljedna bolest, koja skraćuje životni vijek, a uzrokuje je defekt u genu za transmembranski regulator provodljivosti cistične fibroze (eng. cystic fibrosis transmembrane regulator – CFTR). Poremećena je homeostaza elektrolita, što se očituje simptomima u više organskih sustava. Plućne manifestacije, s kroničnim infekcijama, upalom i, na kraju, respiratornim zatajenjem, ostaju i dalje najvažnija prijetnja životnom vijeku bolesnika. Do prije jednog desetljeća bilo je dostupno samo simptomatsko liječenje. Od 2012. g. dostupno je liječenje tzv. modulatorima CFTR-proteina i njihovim kombinacijama za osobe s cističnom fibrozom koje nose različite varijante CFTR-gena. Pojavom tih lijekova uvelike se promijenila perspektiva i kvaliteta života ljudi s cističnom fibrozom, ali postavljeni i novi izazovi u vezi s dugoročnim komplikacijama, pitanje eventualnog smanjenja konvencionalnog liječenja, ali i financiranja terapije, koja je mnogim bolesnicima nedostupna. Iznesene su bazične spoznaje o cističnoj fibrozi i funkciji CFTR-proteina, klasifikaciji varijanata CFTR-gena, mogućnostima liječenja CFTR-modulatorima te osnovni ishodi liječenja bolesnika s cističnom fibrozom u Hrvatskoj, gdje se ta terapija primjenjuje od jeseni 2021. godine.Cystic fibrosis, the most frequent lifespan shortening hereditary disease in Caucasians, is caused by a defect in the CFTR (cystic fibrosis transmembrane regulator) gene. Disturbed electrolyte homeostasis leads to the development of different symptoms in multiple organs. Pulmonary manifestations with chronic infections and inflammation result in respiratory failure and remain the most important life-shortening factor. Until recently only symptomatic treatment was available. In year 2012. a new treatment approach with small molecules that modulate the CFTR protein was introduced. Different combinations of CFTR modulators are applicable to certain patients carrying different variants of the CFTR gene. CFTR modulators made a huge difference in the quality of life and perspectives of people with cystic fibrosis. At the same time, new challenges emerged regarding long term complications and possible reduction of conventional treatment options, as well as financial issues that are an obstacle to the use of these drugs for many patients. This paper brings basic insight into cystic fibrosis, the function of CFTR protein, the classification of CFTR gene variants and possibilities of treatment with CFTR modulators as well as basic outcomes of CFTR modulators treatment in Croatia, where this therapy was introduced in autumn 2021

Synthesis of novel coumarin derivatives by using Pd-catalysed reactions and their structural characterization

U ovom radu opisana je sinteza derivata 7-hidroksikumarina pripravljenih reakcijom bromiranja, nitriranja, te paladijem kataliziranim reakcijama. Bromiranjem 7-hidroksikumarina s N-bromsukcinimidom uz cerijev amonijev nitrat pripravljeni su 8-brom-7-hidroksikumarin (1) i 3,8-dibrom-7-hidroksikumarin (2). Reakcijom nitriranja 7-hidroksikumarina sintetizirani su derivati kumarina supstituirani nitro skupinom u položajima 3 i/ili 6 i 8 kumarinskog prstena (3-5). 7-hidroksi-4-(3-(p-tolil)prop-2-in-1-il)kumarin (6) supstituiran u položaju C-4 pripravljen je Sonogashira-inom reakcijom unakrsnog povezivanja 7-hidroksi-4-klormetilkumarina s 4-metilfenilacetilenom uz Pd-katalizator. Suzuki-jevom reakcijom 7-hidroksi-4-klormetilkumarina s (4-hidroksifenil)bornom kiselinom uz Pd-katalizator sintetiziran je 7-hidroksi-4-(4-hidroksibenzil)kumarin (7). Strukture sintetiziranih spojeva 1-7 potvrđene su 1H NMR spektroskopijom. Derivati kumarina 1-3 spektroskopski su okarakterizirani UV/Vis i fluorimetrijskom spektroskopijom, te su im određeni maksimumi apsorbancije i valne duljine emisije.This work describes the synthesis of 7-hydroxycoumarin derivatives prepared by the bromination, nitration and palladium-catalyzed reactions. 8-bromo-7-hydroxycoumarin (1) and 3,8-dibromo-7-hydroxycoumarin (2) were prepared by the bromination of 7-hydroxycoumarin with N-bromosuccinimide and ceric ammonium nitrate. Coumarin derivates with nitro group substituted at the positions 3 and/ or 6 and 8 of coumarin ring (3-5) were synthesized by the nitration of 7-hydroxycoumarin. 7-hydroxy-4-(3-(p-tolyl)-2-yn-1-yl)-2H-chromen-2-one (6) substituted at C-4 was prepared by Sonogashira cross-coupling reaction of 4-(chloromethyl)-7-hydroxycoumarin and 2-(p-tolyl)ethyn-1-ylium with Pd-catalyst. 7-hydroxy-4-(4-hydroxybenzyl)-2H-chromen-2-one (7) was synthesized by Suzuki reaction of 4-(chloromethyl)-7-hydroxycoumarin and (4-hydroxyphenyl)boronic acid using Pd-catalyst. The structures of the synthesized compounds 1-7 were confirmed by 1H NMR spectroscopy. Coumarin derivates 1-3 were spectroscopically characterized by UV/ Vis and fluorimetric spectroscopy and their maxima of absorbance and emission wavelengths were determined

Electrochemical determination of conductivity for silver patterns prepared using ink-jet printer

U ovom radu opisana je sinteza vodljive tinte na bazi nanočestica srebra. U obje reakcije prekursor, AgNO3 otopljen je i istaložen kao oksid u otopini NaOH. Nakon toga dodan je hidrazin kao reducens te, ovisno o reakciji, poli(akrilna kiselina) ili poli(metakrilna kiselina) kao stabilizator. Nakon sinteze dodan je etilen glikol koji omogućava ravnomjerno sušenje tinte te pufer. Homogenizacija pripravljene tinte provedena je na ultrazvučnoj kupelji. Homogeniziranost smjese praćena je spektrofotometrijski. Dobivenom tintom, uz pomoć inkjet pisača, otisnute su vodljive linije na fleksibilnoj podlozi koje su potom sinterirane na dva načina. Prvo sinteriranje provodilo se u periodima po 20 min u temperaturnom rasponu od 20 do 140 °C dok je drugo sinteriranje uključivalo zagrijavanje na 120 °C u periodima od 30 do 180 min. Sinteriranim linijama, odnosno elektrodama izmjereni su otpori u dvije i četiri točke te su SEM mikroskopijom određene debljine vodljivog sloja. Na temelju izmjerenih veličina izračunate su električne otpornosti otisnutih elektroda čije se minimalne vrijednosti kreću u području od 1,78*10^-8 do 2,77*10^-8 Ωm što je vrlo blizu vrijednosti idealne otpornosti makroskopskog srebra koja iznosi 1,68*10^-8 Ωm. Debljina otisnutog sloja je, osim mikroskopski, određena i elektrokemijski, potenciostatkom metodom primjenom troelektrodnog mjernog sustava. Provedbom ispitivanja uočeno je da prilikom povećanja temperature, odnosno produljenja vremena sinteriranja dolazi do pada otpora, a samim time i do pada otpornosti otisnutih elektroda.This work describes the synthesis of a conductive ink based on silver nanoparticles. In the reactions, the precursor AgNO3 was dissolved in water and precipitated as silver oxide by NaOH. Hydrazine was added as a reducing agent and depending on the reaction, poly(acrylic acid) or poly(methacrylic acid) as a stabilizer. After the synthesis, the ink formulation was performed by homogenization on the ultrasonic bath. Some addition of ethylene glycol to ink formulation enables uniform ink drying while buffer addition enables stable basic ink conditions. Homogenization of the mixture was monitored spectrophotometrically. With the obtained ink and with the aid of a printer, silver lines were printed on a flexible substrate and then sintered in two ways. The first sintering was carried out in periods of 20 minutes at temperatures ranging from 20 to 140 °C while the other sintering involved heating at 120 °C for periods from 30 to 180 minutes. Resistances of the sintered lines or electrodes were measured with two- and four- point measurements while the thickness of the conductive layer was determined using SEM microscopy. Based on the measured dimensions, electrical resistivity of electrodes with minimal values ranging from 1,78*10^-8 to 2,77*10^-8 Ωm were calculated. Obtained results are very close to the ideal macroscopic silver resistivity value of 1,68*10^-8 Ωm. The thickness of the printed layer was, apart from microscopic, determined electrochemically. It has been observed that during the increase of the temperature, or the extension of the sintering time, the resistance drops, and thus the resistivity of the printed electrodes

Electrochemical determination of conductivity for silver patterns prepared using ink-jet printer

U ovom radu opisana je sinteza vodljive tinte na bazi nanočestica srebra. U obje reakcije prekursor, AgNO3 otopljen je i istaložen kao oksid u otopini NaOH. Nakon toga dodan je hidrazin kao reducens te, ovisno o reakciji, poli(akrilna kiselina) ili poli(metakrilna kiselina) kao stabilizator. Nakon sinteze dodan je etilen glikol koji omogućava ravnomjerno sušenje tinte te pufer. Homogenizacija pripravljene tinte provedena je na ultrazvučnoj kupelji. Homogeniziranost smjese praćena je spektrofotometrijski. Dobivenom tintom, uz pomoć inkjet pisača, otisnute su vodljive linije na fleksibilnoj podlozi koje su potom sinterirane na dva načina. Prvo sinteriranje provodilo se u periodima po 20 min u temperaturnom rasponu od 20 do 140 °C dok je drugo sinteriranje uključivalo zagrijavanje na 120 °C u periodima od 30 do 180 min. Sinteriranim linijama, odnosno elektrodama izmjereni su otpori u dvije i četiri točke te su SEM mikroskopijom određene debljine vodljivog sloja. Na temelju izmjerenih veličina izračunate su električne otpornosti otisnutih elektroda čije se minimalne vrijednosti kreću u području od 1,78*10^-8 do 2,77*10^-8 Ωm što je vrlo blizu vrijednosti idealne otpornosti makroskopskog srebra koja iznosi 1,68*10^-8 Ωm. Debljina otisnutog sloja je, osim mikroskopski, određena i elektrokemijski, potenciostatkom metodom primjenom troelektrodnog mjernog sustava. Provedbom ispitivanja uočeno je da prilikom povećanja temperature, odnosno produljenja vremena sinteriranja dolazi do pada otpora, a samim time i do pada otpornosti otisnutih elektroda.This work describes the synthesis of a conductive ink based on silver nanoparticles. In the reactions, the precursor AgNO3 was dissolved in water and precipitated as silver oxide by NaOH. Hydrazine was added as a reducing agent and depending on the reaction, poly(acrylic acid) or poly(methacrylic acid) as a stabilizer. After the synthesis, the ink formulation was performed by homogenization on the ultrasonic bath. Some addition of ethylene glycol to ink formulation enables uniform ink drying while buffer addition enables stable basic ink conditions. Homogenization of the mixture was monitored spectrophotometrically. With the obtained ink and with the aid of a printer, silver lines were printed on a flexible substrate and then sintered in two ways. The first sintering was carried out in periods of 20 minutes at temperatures ranging from 20 to 140 °C while the other sintering involved heating at 120 °C for periods from 30 to 180 minutes. Resistances of the sintered lines or electrodes were measured with two- and four- point measurements while the thickness of the conductive layer was determined using SEM microscopy. Based on the measured dimensions, electrical resistivity of electrodes with minimal values ranging from 1,78*10^-8 to 2,77*10^-8 Ωm were calculated. Obtained results are very close to the ideal macroscopic silver resistivity value of 1,68*10^-8 Ωm. The thickness of the printed layer was, apart from microscopic, determined electrochemically. It has been observed that during the increase of the temperature, or the extension of the sintering time, the resistance drops, and thus the resistivity of the printed electrodes

Electrochemical determination of conductivity for silver patterns prepared using ink-jet printer

U ovom radu opisana je sinteza vodljive tinte na bazi nanočestica srebra. U obje reakcije prekursor, AgNO3 otopljen je i istaložen kao oksid u otopini NaOH. Nakon toga dodan je hidrazin kao reducens te, ovisno o reakciji, poli(akrilna kiselina) ili poli(metakrilna kiselina) kao stabilizator. Nakon sinteze dodan je etilen glikol koji omogućava ravnomjerno sušenje tinte te pufer. Homogenizacija pripravljene tinte provedena je na ultrazvučnoj kupelji. Homogeniziranost smjese praćena je spektrofotometrijski. Dobivenom tintom, uz pomoć inkjet pisača, otisnute su vodljive linije na fleksibilnoj podlozi koje su potom sinterirane na dva načina. Prvo sinteriranje provodilo se u periodima po 20 min u temperaturnom rasponu od 20 do 140 °C dok je drugo sinteriranje uključivalo zagrijavanje na 120 °C u periodima od 30 do 180 min. Sinteriranim linijama, odnosno elektrodama izmjereni su otpori u dvije i četiri točke te su SEM mikroskopijom određene debljine vodljivog sloja. Na temelju izmjerenih veličina izračunate su električne otpornosti otisnutih elektroda čije se minimalne vrijednosti kreću u području od 1,78*10^-8 do 2,77*10^-8 Ωm što je vrlo blizu vrijednosti idealne otpornosti makroskopskog srebra koja iznosi 1,68*10^-8 Ωm. Debljina otisnutog sloja je, osim mikroskopski, određena i elektrokemijski, potenciostatkom metodom primjenom troelektrodnog mjernog sustava. Provedbom ispitivanja uočeno je da prilikom povećanja temperature, odnosno produljenja vremena sinteriranja dolazi do pada otpora, a samim time i do pada otpornosti otisnutih elektroda.This work describes the synthesis of a conductive ink based on silver nanoparticles. In the reactions, the precursor AgNO3 was dissolved in water and precipitated as silver oxide by NaOH. Hydrazine was added as a reducing agent and depending on the reaction, poly(acrylic acid) or poly(methacrylic acid) as a stabilizer. After the synthesis, the ink formulation was performed by homogenization on the ultrasonic bath. Some addition of ethylene glycol to ink formulation enables uniform ink drying while buffer addition enables stable basic ink conditions. Homogenization of the mixture was monitored spectrophotometrically. With the obtained ink and with the aid of a printer, silver lines were printed on a flexible substrate and then sintered in two ways. The first sintering was carried out in periods of 20 minutes at temperatures ranging from 20 to 140 °C while the other sintering involved heating at 120 °C for periods from 30 to 180 minutes. Resistances of the sintered lines or electrodes were measured with two- and four- point measurements while the thickness of the conductive layer was determined using SEM microscopy. Based on the measured dimensions, electrical resistivity of electrodes with minimal values ranging from 1,78*10^-8 to 2,77*10^-8 Ωm were calculated. Obtained results are very close to the ideal macroscopic silver resistivity value of 1,68*10^-8 Ωm. The thickness of the printed layer was, apart from microscopic, determined electrochemically. It has been observed that during the increase of the temperature, or the extension of the sintering time, the resistance drops, and thus the resistivity of the printed electrodes