Синтез та антимікробна активність 1-алкіл-5-метил-3-феніл-6-(5-феніл-1,3,4-оксадіазол-2-іл)тієно[2,3-d]піримідин-2,4(1H,3H)-діонів

An effective approach for synthesis of 5-methyl-3-phenyl-6-(5-phenyl-1,3,4-oxadiazol-2-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione by 1,1’-carbonyldiimidazole promoted interaction of 5-methyl-2,4-dioxo-3-phenyl-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidine-6-carboxylic acid with benzohydrazide has been developed. The procedure also includes cyclization of N’-benzoyl-5-methyl-2,4-dioxo-3-phenyl-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidine-6-carbohydrazide obtained by boiling in phosphorous oxychloride and further hydrolysis of the chlorine atom at position 2 of the thieno[2,3-d]pyrimidine system. Alkylation of the assembly of two heterocyclic units obtained with benzyl chlorides, chloroacetamides, and 5-(chloromethyl)-3-aryl-1,2,4-oxadiazoles has allowed obtaining of 1-alkyl-5-methyl-3-phenyl-6-(5-phenyl-1,3,4-oxadiazol-2-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-diones. The structures of the compounds obtained have been confirmed by the 1H NMR, chromato-mass spectral and elemental microanalysis data. The results of the screening performed by the agar diffusion method (“well method”) have shown the absence of the antimicrobial activity for 1-benzyl-5-methyl-3-phenyl-6-(5-phenyl-1,3,4-oxadiazol-2-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-diones and 2-[5-methyl-2,4-dioxo-3-phenyl-6-(5-phenyl-1,3,4-oxadiazol-2-yl)-3,4-dihydrothieno[2,3-d]pyrimidin-1(2H)-yl]-N-arylacetamides; but the activity for 1-{[3-aryl-1,2,4-oxadiazol-5-yl]methyl}-5-methyl-3-phenyl-6-(5-phenyl-1,3,4-oxadiazol-2-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-diones has been found. The compounds of this range appeared to be active against the strains of Staphylococcus aureus, Escherichia coli and Bacillus subtilis; the diameters of their growth inhibition zones were similar to those for the reference drugs Metronidazole and Streptomycin.Разработан эффективный подход к синтезу 5-метил-3-фенил-6-(5-фенил-1,3,4-оксадиазол-2-ил)тиено[2,3-d]пиримидин-2,4(1H,3H)-диона путем промотированного 1,1’-карбонилдиимидазолом взаимодействия 5-метил-2,4-диоксо-3-фенил-1,2,3,4-тетрагидротиено[2,3-d]пиримидин-6-карбоновой кислоты с бензогидразидом. Процедура также включает циклизацию полученного N’-бензоил-5-метил-2,4-диоксо-3-фенил-1,2,3,4-тетрагидротиено[2,3-d]пиримидин-6-карбогидразида кипячением в хлорокиси фосфора и дальнейший гидролиз атома хлора в положении 2 тиено[2,3-d]пиримидиновой системы. Алкилирование полученного двухзвенного ансамбля гетероциклов бензилхлоридами, хлорацетамидами и 5-(хлорметил)-3-арил-1,2,4-оксадиазолами позволило получить 1-алкил-5-метил-3-фенил-6-(5-фенил-1,3,4-оксадиазол-2-ил)тиено[2,3-d]пиримидин-2,4(1H,3H)-дионы. Структуры полученных соединений были подтверждены на основе данных 1Н ЯМР, хроматомас спектров и элементного анализа. По результатам скрининга методом диффузии в агар («метод колодцев») установлено отсутствие противомикробной активности у 1-бензил-5-метил-3-фенил-6-(5-фенил-1,3,4-оксадиазол-2-ил)тиено[2,3-d]пиримидин-2,4(1H,3H)-дионов и 2-[5-метил-2,4-диоксо-3-фенил-6-(5-фенил-1,3,4-оксадиазол-2-ил)-3,4-дигидротиено[2,3-d]пиримидин-1(2H)-ил]-N-арилацетамидов, а также наличие противомикробной активности для 1-{[3-арил-1,2,4-оксадиазол-5-ил]метил}-5-метил-3-фенил-6-(5-фенил-1,3,4-оксадиазол-2-ил)тиено[2,3-d]пиримидин-2,4(1H,3H)-дионов. Данные вещества проявили противомикробную активность к штаммам Staphylococcus aureus, Escherichia coli и Baсillus subtilis со значениями зон задержки роста, близкими к препаратам сравнения метронидазолу и стрептомицину.Розроблено ефективний підхід до синтезу 5-метил-3-феніл-6-(5-феніл-1,3,4-оксадіазол-2-іл)тієно[2,3-d]піримідин-2,4(1H,3H)-діону шляхом промотованої 1,1’-карбонілдіімідазолом взаємодії 5-метил-2,4-діоксо-3-феніл-1,2,3,4-тетрагідротієно[2,3-d]піримідин-6-карбонової кислоти з бензогідразидом. Процедура також включає наступну циклізацію отриманого N’-бензоїл-5-метил-2,4-діоксо-3-феніл-1,2,3,4-тетра-гідротієно[2,3-d]піримідин-6-карбогідразиду кип’ятінням у хлорокисі фосфору та подальший гідроліз атома хлору у положенні 2 тієно[2,3-d]піримідинової системи. Алкілювання отриманого дволанкового ансамблю гетероциклів бензилхлоридами, хлороацетамідами та 5-(хлорометил)-3-арил-1,2,4-оксадіазо-лами дозволило отримати 1-алкіл-5-метил-3-феніл-6-(5-феніл-1,3,4-оксадіазол-2-іл)тієно[2,3-d]піримі-дин-2,4(1H,3H)-діони. Структури отриманих сполук були підтверджені на основі даних 1Н ЯМР, хроматомас спектрів та елементного аналізу. За результатами скринінгу методом дифузії в агар («метод колодязів») встановлено відсутність антимікробної активності у 1-бензил-5-метил-3-феніл-6-(5-феніл-1,3,4-оксадіазол-2-іл)тієно[2,3-d]піримідин-2,4(1H,3H)-діонів та 2-[5-метил-2,4-діоксо-3-феніл-6-(5-феніл-1,3,4-оксадіазол-2-іл)-3,4-дигідротієно[2,3-d]піримідин-1(2H)-іл]-N-арилацетамідів, а також наявність антимікробної активності для 1-{[3-арил-1,2,4-оксадіазол-5-іл]метил}-5-метил-3-феніл-6-(5-феніл-1,3,4-окса-діазол-2-іл)тієно[2,3-d]піримідин-2,4(1H,3H)-діонів. Дані речовини виявили антимікробну активність до штамів Staphylococcus aureus, Escherichia coli та Baсillus subtilis із значеннями зон затримки росту, близькими до препаратів порівняння метронідазолу та стрептоміцину

Pair decay width of the Hoyle state and carbon production in stars

Electron scattering off the first excited 0+ state in 12C (the Hoyle state) has been performed at low momentum transfers at the S-DALINAC. The new data together with a novel model-independent analysis of the world data set covering a wide momentum transfer range result in a highly improved transition charge density from which a pair decay width Gamma_pi = (62.3 +- 2.0) micro-eV of the Hoyle state was extracted reducing the uncertainty of the literature values by more than a factor of three. A precise knowledge of Gamma_pi is mandatory for quantitative studies of some key issues in the modeling of supernovae and of asymptotic giant branch stars, the most likely site of the slow-neutron nucleosynthesis process.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

How quantum bound states bounce and the structure it reveals

We investigate how quantum bound states bounce from a hard surface. Our analysis has applications to ab initio calculations of nuclear structure and elastic deformation, energy levels of excitons in semiconductor quantum dots and wells, and cold atomic few-body systems on optical lattices with sharp boundaries. We develop the general theory of elastic reflection for a composite body from a hard wall. On the numerical side we present ab initio calculations for the compression of alpha particles and universal results for two-body states. On the analytical side we derive a universal effective potential that gives the reflection scattering length for shallow two-body states.Comment: final publication version, new lattice results on alpha particle compression, 5 pages, 2 figure

Signal recognition and background suppression by matched filters and neural networks for Tunka-Rex

The Tunka Radio Extension (Tunka-Rex) is a digital antenna array, which measures the radio emission of the cosmic-ray air-showers in the frequency band of 30-80 MHz. Tunka-Rex is co-located with TAIGA experiment in Siberia and consists of 63 antennas, 57 of them are in a densely instrumented area of about 1 km\textsuperscript{2}. In the present work we discuss the improvements of the signal reconstruction applied for the Tunka-Rex. At the first stage we implemented matched filtering using averaged signals as template. The simulation study has shown that matched filtering allows one to decrease the threshold of signal detection and increase its purity. However, the maximum performance of matched filtering is achievable only in case of white noise, while in reality the noise is not fully random due to different reasons. To recognize hidden features of the noise and treat them, we decided to use convolutional neural network with autoencoder architecture. Taking the recorded trace as an input, the autoencoder returns denoised trace, i.e. removes all signal-unrelated amplitudes. We present the comparison between standard method of signal reconstruction, matched filtering and autoencoder, and discuss the prospects of application of neural networks for lowering the threshold of digital antenna arrays for cosmic-ray detection.Comment: ARENA2018 proceeding

Current Status and New Challenges of The Tunka Radio Extension

The Tunka Radio Extension (Tunka-Rex) is an antenna array spread over an area of about 1~km$^2$. The array is placed at the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) and detects the radio emission of air showers in the band of 30 to 80~MHz. During the last years it was shown that a sparse array such as Tunka-Rex is capable of reconstructing the parameters of the primary particle as accurate as the modern instruments. Based on these results we continue developing our data analysis. Our next goal is the reconstruction of cosmic-ray energy spectrum observed only by a radio instrument. Taking a step towards it, we develop a model of aperture of our instrument and test it against hybrid TAIGA observations and Monte-Carlo simulations. In the present work we give an overview of the current status and results for the last five years of operation of Tunka-Rex and discuss prospects of the cosmic-ray energy estimation with sparse radio arrays.Comment: Proceedings of E+CRS 201

Improved measurements of the energy and shower maximum of cosmic rays with Tunka-Rex

The Tunka Radio Extension (Tunka-Rex) is an array of 63 antennas located in the Tunka Valley, Siberia. It detects radio pulses in the 30-80 MHz band produced during the air-shower development. As shown by Tunka-Rex, a sparse radio array with about 200 m spacing is able to reconstruct the energy and the depth of the shower maximum with satisfactory precision using simple methods based on parameters of the lateral distribution of amplitudes. The LOFAR experiment has shown that a sophisticated treatment of all individually measured amplitudes of a dense antenna array can make the precision comparable with the resolution of existing optical techniques. We develop these ideas further and present a method based on the treatment of time series of measured signals, i.e. each antenna station provides several points (trace) instead of a single one (amplitude or power). We use the measured shower axis and energy as input for CoREAS simulations: for each measured event we simulate a set of air-showers with proton, helium, nitrogen and iron as primary particle (each primary is simulated about ten times to cover fluctuations in the shower maximum due to the first interaction). Simulated radio pulses are processed with the Tunka-Rex detector response and convoluted with the measured signals. A likelihood fit determines how well the simulated event fits to the measured one. The positions of the shower maxima are defined from the distribution of chi-square values of these fits. When using this improved method instead of the standard one, firstly, the shower maximum of more events can be reconstructed, secondly, the resolution is increased. The performance of the method is demonstrated on the data acquired by the Tunka-Rex detector in 2012-2014.Comment: Proceedings of the 35th ICRC 2017, Busan, Kore