Effect of cations (Mg2+, Zn2+, Cd2+) on formation of the mineral phase in Ca(NO3)2-Mg(NO3)2-Na2HPO4-H2O system

Synthesis of hydroxyapatite in the system Ca(NO3)2-Me(NO3)2-NaHPO4-H2O with pH in the range of 6-12.2 is performed, and hydroxyapatite of B-type is formed. The effect of magnesium, zinc and cadmium ions on the properties of hydroxyapatite is studied. It is shown that as the concentration of these ions increases, the crystallinity of hydroxyapatite and the Ca/P ratio decreases. It is found that in all the experiments Zn2+ cations affect the hydroxyapatite structure to a lesser extent which results in less structural defects, wherein the Ca/P ratio attains the highest values. It is shown that the solubility of the samples containing zinc ions is greater than that of the samples with other additives

Синтез, протимікробна активність та докінгові дослідження 6-(1H-бензімідазол-2- іл)-5-метилтієно[2,3-d]піримідин-4(3H)-онів з ацетамідними та 1,2,4-оксадіазол-5- ілметильними замісниками

Aim. To synthesize, study the antimicrobial activity and suggest antimicrobial activity mechanism for the novel derivatives of 6-(1H-benzimidazol-2-yl)-5-methylthieno[2,3-d]pyrimidin-4(3H)-one. Results and discussion. As the result of the targeted modification of 6-(1H-benzimidazol-2-yl)-5-methylthieno[2,3-d]-pyrimidin-4(3H)-one in position 3 with acetamide and 1,2,4-oxadiazol-5-ylmethyl substituents, the compounds, which demonstrated better antimicrobial activity in the agar well diffusion assay than the reference drug Streptomycin, were obtained. To elucidate the mechanism of action of the novel compounds, the docking studies were con-ducted to the active site of the 16S subunit of ribosomal RNA, the proven target for aminoglycoside antibiotics, as well as tRNA (Guanine37-N1)-methyltransferase (TrmD), which inhibitors were considered as a new potential class of antibiotics. Experimental part. By the interaction of 6-(1H-benzimidazol-2-yl)-5-methylthieno[2,3-d]pyrimidin-4(3H)-one with a series of N-arylchloroacetamides and 3-aryl-5-(chloromethyl)-1,2,4-oxadiazoles in DMF in the presence of K2CO3 the target compounds were obtained. The antimicrobial activity was assessed by the agar well diffusion method. The concentration of microbial cells was determined by the McFarland standard; the value was 107 cells in 1 mL of the media. The 18 – 24 hour culture of microorganisms was used for tests. For the bacteria cultivation, Müller-Hinton agar was used, Sabouraud agar was applied for C. albicans cultivation. The compounds were tested as the DMSO solution with the concentration of 100 µg/mL; the volume of the solution was 0.3 mL, the same volume was used for Streptomycin (the concentration 30 µg/mL). The docking studies were performed using Autodock Vina. Crystallographic data for the complexes of Streptomycin with the 16S subunit of ribosomal RNA (1NTB) and its active site, as well as for tRNA (Guanine37-N1)-methyltransferase (EC 2.1.1.228; TrmD) (5ZHN) and its active site were obtained from the Protein Data Bank.Conclusions. It has been determined that 2-[6-(1H-benzimidazol-2-yl)-5-methyl-4-oxothieno[2,3-d]pyrimidin-3(4H)-yl]-N-[4-(ethoxy)phenyl]acetamide, which is the most active as an antimicrobial agent among the compounds tested, also shows the best binding activity towards the active site of tRNA (guanine37-N1)-methyltransferase.Мета. Синтезувати й дослідити протимікробну активність нових похідних 6-(1H-бензімідазол-2-іл)-5-метилтієно[2,3-d]піримідин-4(3H)-онів та запропонувати механізм протимікробної активності.Результати та їх обговорення. У результаті цілеспрямованої модифікації положення 3 6-(1H-бензімідазол-2-іл)-5-метилтієно[2,3-d]піримідин-4(3H)-ону ацетамідним та 1,2,4-оксадіазол-5-ілметильним замісниками було одержано сполуки з визначеною методом дифузії в агар протимікробною активністю, що є більшою за активність препарату порівняння Стрептоміцину. З метою з’ясування механізму дії синтезованих сполук було проведено докінгові дослідження щодо активного сайту субодиниці 16S рибосомальної РНК, яка є підтвердженою мішенню для аміноглікозидних антибіотиків, а також тРНК (Гуанін-37-N1)-метилтрансферази (TrmD), інгібітори якої розглядаються як новий потенційний клас антибіотиків. Експериментальна частина. Шляхом взаємодії 6-(1H-бензімідазол-2-іл)-5-метилтієно[2,3-d]піримідин-4(3H)-ону з рядом N-арилхлороацетамідів та 3-арил-5-(хлорометил)-1,2,4-оксадіазолів в умовах ДМФА-K2CO3 було одержано цільові сполуки. Антимікробну активність визначали методом дифузії в агар. Концентрацію мікробних клітин визначали за МакФарландом; мікробне навантаження склало 107 мікробних одиниць в 1 мл середовища. Для тестів використовували 18 – 24 годинну культуру мікроорганізмів. Для культивування бактерій використовували агар Мюллера-Гінтона; для культивування C. albicans використовували агар Сабуро. Сполуки вводили методом дифузії в агар (лунками) у вигляді розчину у ДМСО в концентрації 100 мкг/мл в об’ємі 0,3 мл; аналогічний об’єм використовували для Стрептоміцину (конц. 30 мкг/мл). Докінгові дослідження проводили за допомогою програми Autodock Vina. Кристалографічні дані для комплексів стрептоміцину з 16S субодиницею рибосомальної РНК (1NTB) та її активного сайту і для тРНК (Гуанін-37-N1)-метилтрансферази (EC 2.1.1.228; TrmD) (5ZHN) та її активного сайту було отримано з Protein Data Bank.Висновки. Виявлено, що сполука 2-[6-(1H-бензімідазол-2-іл)-5-метил-4-оксотієно[2,3-d]піримідин-3(4H)-іл]-N-[4-(етокси)феніл]ацетамід, яка характеризується найбільшою протимікробною активністю, у докінгових розрахунках є також найбільш ефективним інгібітором тРНК (Гуанін-37-N1)-метилтрансферази

Effect of cations (Mg2+, Zn2+, Cd2+) on formation of the mineral phase in Ca(NO3)2-Mg(NO3)2-Na2HPO4-H2O system

Synthesis of hydroxyapatite in the system Ca(NO3)2-Me(NO3)2-NaHPO4-H2O with pH in the range of 6-12.2 is performed, and hydroxyapatite of B-type is formed. The effect of magnesium, zinc and cadmium ions on the properties of hydroxyapatite is studied. It is shown that as the concentration of these ions increases, the crystallinity of hydroxyapatite and the Ca/P ratio decreases. It is found that in all the experiments Zn2+ cations affect the hydroxyapatite structure to a lesser extent which results in less structural defects, wherein the Ca/P ratio attains the highest values. It is shown that the solubility of the samples containing zinc ions is greater than that of the samples with other additives

Preparation and Electron-Beam Surface Modification of Novel TiNi Material for Medical Applications

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations

Synthesis and Antimicrobial Activity of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)-2H-chromen-2-ones

The aim of this work is to study methods of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)-2H-chromen-2-ones preparation and their antimicrobial activity.Materials and methods. 1Н NMR spectra were recorded on Varian Mercury-200 (200 MHz), 13C NMR spectra were acquired on Bruker Avance 500 1H NMR (500 MHz) and 13C NMR (125 MHz) in DMSO-d6 and CDCl3. LC-MS analysis of compounds was performed on an Agilent 1100 HPLC instrument with chemical ionization at atmospheric pressure (APCI). The study of antimicrobial activity of compounds was performed by agar well diffusion method. The docking studies were performed using Autodock Vina.Results and discussion. The interaction of 3-(2-bromopropanoyl)-2H-chromen-2-ones with N-substituted thioureas produced novel derivatives of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)chromen-2-ones. The study of antimicrobial activity of the obtained compounds allowed to identify active samples against E. сoli and P. aeruginosa strains. Among the tested compounds, 8-methoxy-3-{2-[(2-methoxyphenyl)amino]-5-methyl-1,3-thiazol-4-yl}-2H-chromen-2-one showed higher activity than the reference drug Streptomycin against E. coli strain. Some compounds showed high activity against P. aeruginosa. Docking studies of the synthesized compounds indicated that they can bind in the active site to bacterial tRNA (guanine37-N1)-methyltransferase.Conclusions. Novel derivatives of 2H-chromen-2-ones with 2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol moiety at the position 3 were obtained by the Hantzsch thiazole synthesis starting from 3-(2-bromopropanoyl)-2H-chromen-2-ones. Studies of antimicrobial activity allowed to identify new 2H-chromen-2-one derivatives as equipotent antimicrobial agents to the reference drug Streptomycin or even more potent. The docking studies revealed that the synthesized compounds may be inhibitors of tRNA (guanine37-N1)-methyltransferase, which is a crucial enzyme for survival of different bacteria, e.g. P. aeruginosa during stress condition

Synthesis and Antimicrobial Activity of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)-2H-chromen-2-ones

The aim of this work is to study methods of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)-2H-chromen-2-ones preparation and their antimicrobial activity.Materials and methods. 1Н NMR spectra were recorded on Varian Mercury-200 (200 MHz), 13C NMR spectra were acquired on Bruker Avance 500 1H NMR (500 MHz) and 13C NMR (125 MHz) in DMSO-d6 and CDCl3. LC-MS analysis of compounds was performed on an Agilent 1100 HPLC instrument with chemical ionization at atmospheric pressure (APCI). The study of antimicrobial activity of compounds was performed by agar well diffusion method. The docking studies were performed using Autodock Vina.Results and discussion. The interaction of 3-(2-bromopropanoyl)-2H-chromen-2-ones with N-substituted thioureas produced novel derivatives of 3-(2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol-4-yl)chromen-2-ones. The study of antimicrobial activity of the obtained compounds allowed to identify active samples against E. сoli and P. aeruginosa strains. Among the tested compounds, 8-methoxy-3-{2-[(2-methoxyphenyl)amino]-5-methyl-1,3-thiazol-4-yl}-2H-chromen-2-one showed higher activity than the reference drug Streptomycin against E. coli strain. Some compounds showed high activity against P. aeruginosa. Docking studies of the synthesized compounds indicated that they can bind in the active site to bacterial tRNA (guanine37-N1)-methyltransferase.Conclusions. Novel derivatives of 2H-chromen-2-ones with 2-N-(aryl,acyl)amino-5-methyl-1,3-thiazol moiety at the position 3 were obtained by the Hantzsch thiazole synthesis starting from 3-(2-bromopropanoyl)-2H-chromen-2-ones. Studies of antimicrobial activity allowed to identify new 2H-chromen-2-one derivatives as equipotent antimicrobial agents to the reference drug Streptomycin or even more potent. The docking studies revealed that the synthesized compounds may be inhibitors of tRNA (guanine37-N1)-methyltransferase, which is a crucial enzyme for survival of different bacteria, e.g. P. aeruginosa during stress condition

Synthesis, in silico and in vitro antimicrobial activity of N-(benzyl)-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides

According to the recent studies bezylcarboxamide fragment attached to the thiophene ring of thieno[2,3-d]pyrimidine is beneficial for antimicrobial activity of the compounds. Therefore we focused our efforts on constructing of the simple molecules such as N-(benzyl)-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides to get deeper insight into their antimicrobial activity. As the optimal procedure for preparation of target compounds we choose 1,1’-carbonyldiimidazole promoted interaction of 5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylic acid with the series of substituted benzyl amines. The obtained amides showed good activity against the strains of S. aureus and B. subtilis, which was higher for the derivative without substituents in benzene ring or the compounds with small substituents like methyl or methoxyl groups in the para-position of the benzene ring. Docking studies showed that despite the good values of the scoring functions, the conformational analysis of the ligands’ poses in the active site revealed their ability for only partial inhibition of TrmD of P. aeruginosa

Synthesis, in silico and in vitro antimicrobial activity of N-(benzyl)-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides

According to the recent studies bezylcarboxamide fragment attached to the thiophene ring of thieno[2,3-d]pyrimidine is beneficial for antimicrobial activity of the compounds. Therefore we focused our efforts on constructing of the simple molecules such as N-(benzyl)-5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamides to get deeper insight into their antimicrobial activity. As the optimal procedure for preparation of target compounds we choose 1,1’-carbonyldiimidazole promoted interaction of 5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxylic acid with the series of substituted benzyl amines. The obtained amides showed good activity against the strains of S. aureus and B. subtilis, which was higher for the derivative without substituents in benzene ring or the compounds with small substituents like methyl or methoxyl groups in the para-position of the benzene ring. Docking studies showed that despite the good values of the scoring functions, the conformational analysis of the ligands’ poses in the active site revealed their ability for only partial inhibition of TrmD of P. aeruginosa

Synthesis and Antimicrobial Evaluation of 2-(6-Imidazo[1,2-a]pyridin-2-yl-5-methyl-2,4-dioxo-3-phenyl-3,4-dihydrothieno[2,3-d]pyrimidin-1(2H)-yl)-N-arylacetamide Derivatives

6-Heteryl-5-methylthieno[2,3-d]pyrimidin-2,4(1H,3H)-diones are of great interest as the promising objects for the search of antibacterials. In this communication, we obtained 6-(imidazo[1,2-a]pyridin-2-yl)-5-methyl-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione by interaction of 6-(bromoacetyl)-5-methyl-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione with 2-aminopyridine. The obtained heterocyclic hybrid was further modified by alkylation with 2-chloroarylacetamides. Antimicrobial activity studies for the synthesized compounds using the agar well diffusion method revealed their moderate activity against S. aureus, E. coli and B. subtilis. According to the double dilution assay MIC value results for 6-(imidazo[1,2-a]pyridin-2-yl)-5-methyl-3-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneagainst P. aeruginosa was less than the value determined for the reference drug streptomycin. The docking study of the synthesized compounds to the active site of TrmD isolated from P. aeruginosa did not show their effective inhibitory activity

Design, Synthesis and In Vitro Antimicrobial Activity of 6-(1<i>H</i>-Benzimidazol-2-yl)-3,5-dimethyl-4-oxo-2-thio-3,4-dihydrothieno[2,3-<i>d</i>]pyrimidines

The rapid development in bacterial resistance to many groups of known antibiotics forces the researchers to discover antibacterial drug candidates with previously unknown mechanisms of action, one of the most relevant being the inhibition of tRNA (Guanine37-N1)-methyltransferase (TrmD). The discovery of selective TrmD inhibitors in the series of carboxamide derivatives of thienopyrimidines became a background for further modification of the similar structures aimed at the development of promising antibacterial agents. As part of this research, we carried out the construction of heterocyclic hybrids bearing the moieties of thieno[2,3-d]pyrimidine and benzimidazole starting from 3,5-dimethyl-4-oxo-2-thioxo-1H-thieno[2,3-d]pyrimidine-6-carboxylic acid, which was used as the pivotal intermediate. The hybrid molecule of 6-(1H-benzimidazol-2-yl)-3,5-dimethyl-2-thioxo-1H-thieno[2,3-d]pyrimidin-4-one prepared via condensation of the carboxylic acid with ortho-phenylenediamine was further alkylated with aryl/hetaryl chloroacetamides and benzyl chloride to produce the series of S-alkyl derivatives. The results of molecular docking studies for the obtained series of S-alkyl benzimidazole-thienopyrimidines showed their high affinity to the TrmD isolated from the P. aeruginosa. The results of antimicrobial activity screening revealed the antimicrobial properties for all of the studied molecules against both Gram-positive and Gram-negative bacteria and the Candida albicans fungal strain. The highest antimicrobial activity was determined for 2-{[6-(1H-benzimidazol-2-yl)-3,5-dimethyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidin-2-yl]thio}-N-(4-isopropylphenyl)acetamide, which also had the highest affinity to the TrmD inhibitor’s binding site according to the docking studies results