65 research outputs found
POLYFUNCTIONAL PYRAZOLES. 10*. SYNTHESIS OF 5-OXO-4,5,7,9-TETRAHYDROPYRAZOLO[3,4-е][1,2,3]- TRIAZOLO[1,5-а][1,3]DIAZEPINE-3-CARBOXAMIDES IN A TANDEM REACTION OF ETHYL 4-(AZIDO- METHYL)PYRAZOLE-3-CARBOXYLATES WITH CYANOACETAMIDES
4-(Azidomethyl)pyrazole-3-carboxylic acid ethyl esters react with cyanoacetamides in THF solution in the presence of t-BuOK resulting in the formation of 5-oxo-4,5,7,9-tetrahydropyrazolo[3,4-e][1,2,3]-triazolo[1,5-a][1,3]diazepine-3-carboxamides
POLYFUNCTIONAL PYRAZOLES. 9*. SYNTHESIS OF 1-ALKYL(ARYL)-3-[4-(HYDROXYMETHYL)-1Н-PYRAZOL-3-YL]UREAS
We have developed an effective method for the preparation of 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1Н-pyrazol-3-yl]ureas based on the interaction of 4-hydroxymethylpyrazole-3-carbonyl azides with primary aliphatic and aromatic amines under the conditions of Curtius reaction. In the absence of amines in the reaction mixture, in situ generated 4-hydroxymethyl-3-isocyanatopyrazoles underwent intramolecular cyclization to pyrazolo[3,4-d][1,3]oxazin-6(4Н)-ones. The latter showed a tendency to form 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1Н-pyrazol-3-yl]ureas in the presence of amines
Polyfunctional pyrazoles. 9. Synthesis of 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1h-pyrazol-3-yl]ureas
We have developed an effective method for the preparation of 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1Н-pyrazol-3-yl]ureas based on the interaction of 4-hydroxymethylpyrazole-3-carbonyl azides with primary aliphatic and aromatic amines under the conditions of Curtius reaction. In the absence of amines in the reaction mixture, in situ generated 4-hydroxymethyl-3-isocyanatopyrazoles underwent intramolecular cyclization to pyrazolo[3,4-d][1,3]oxazin-6(4Н)-ones. The latter showed a tendency to form 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1Н-pyrazol-3-yl]ureas in the presence of amine
Polyfunctional Imidazoles: VIII.* 1-Aryl-4-chloro- 5-[R-sulfanyl(R-sulfonyl)methyl]-1H-imidazoles
Alkylation of (1-aryl-4-chloro-1H-imidazol-5-yl)methanethiols with alkyl halides, propargyl bromide, or chloroacetic acid gave 1-aryl-5-(R-sulfanylmethyl)-4-chloro-1H-imidazoles. 1-Aryl-4-chloro-5-(methylsulfanylmethyl)-1H-imidazoles and [(1-aryl-4-chloro-1H-imidazol-5-yl)methylsulfanyl]acetic acids were oxidized to the corresponding sulfones with potassium permanganate.Кафедра фармаці
ВПРОВАДЖЕННЯ ІНТЕРАКТИВНОГО НАВЧАННЯ В ПРАКТИКУ ПОЧАТКОВОЇ ШКОЛИ
The ways of introduction of the interactive teaching are exposed in the article, essence of the interactive teaching is lighted up; the groups of interactive methods of teaching are described
Effect of Long Aging on the Resistivity Properties of Aluminum Doped YBa2Cu3−y Al y O7−δ Single Crystals with a Given Twin Boundary Topology
α,α-Difluoro-β-ketophosphonates on a tetraazamacrocyclic platform: Synthesis and inhibitory activity against protein tyrosine phosphatases
The present study offers a new approach for designing inhibitors of protein tyrosine phosphatases. We have synthesized the cyclam derivatives with α,α-difluoro-β-ketophosphonate fragments
covalently attached to tetraazamacrocyclic scaffold, which is known to be of medical interest.
The obtained functionalized macrocycles were evaluated as inhibitors of PTP1B, TC-PTP,
CD45, and other protein tyrosine phosphatases.Запроновано новий пiдхiд до розробки iнгiбiторiв протеїнтирозинфосфатаз. Синтезовано
похiднi цикламу з α,α-дифторо-β-кетофосфонатними фрагментами, ковалентно зв’язаними з тетраазамакроциклiчною платформою. Отриманi функцiоналiзованi макроцикли було
дослiджено як iнгiбiтори PTP1B, TC-PTP, CD45 та iнших протеїнтирозинфосфатаз.Предложен новый поход к разработке ингибиторов протеинтирозинфосфатаз. Синтезированы производные циклама с α,α-дифтор-β-кетофосфонатными фрагментами, ковалентно
связанными с тетраазамакроциклической платформой. Полученные функционализированные макроциклы были изучены в качестве ингибиторов PTP1B, TC-PTP, CD45 и других
протеинтирозинфосфатаз
Detection of persistent VHE gamma-ray emission from PKS 1510-089 by the MAGIC telescopes during low states between 2012 and 2017
PKS 1510-089 is a flat spectrum radio quasar strongly variable in the optical and GeV range. To date, very high-energy (VHE, > 100 GeV) emission has been observed from this source either during long high states of optical and GeV activity or during short flares. Aims. We search for low-state VHE gamma-ray emission from PKS 1510-089. We characterize and model the source in a broadband context, which would provide a baseline over which high states and flares could be better understood. Methods. PKS 1510-089 has been monitored by the MAGIC telescopes since 2012. We use daily binned Fermi-LAT flux measurements of PKS 1510-089 to characterize the GeV emission and select the observation periods of MAGIC during low state of activity. For the selected times we compute the average radio, IR, optical, UV, X-ray, and gamma-ray emission to construct a low-state spectral energy distribution of the source. The broadband emission is modeled within an external Compton scenario with a stationary emission region through which plasma and magnetic fields are flowing. We also perform the emission-model-independent calculations of the maximum absorption in the broad line region (BLR) using two different models. Results. The MAGIC telescopes collected 75 hr of data during times when the Fermi-LAT flux measured above 1 GeV was below 3? × 10 -8 ? cm -2 ? s -1 , which is the threshold adopted for the definition of a low gamma-ray activity state. The data show a strongly significant (9.5¿) VHE gamma-ray emission at the level of (4.27 ± 0.61 stat ) × 10 -12 ? cm -2 ? s -1 above 150 GeV, a factor of 80 lower than the highest flare observed so far from this object. Despite the lower flux, the spectral shape is consistent with earlier detections in the VHE band. The broadband emission is compatible with the external Compton scenario assuming a large emission region located beyond the BLR. For the first time the gamma-ray data allow us to place a limit on the location of the emission region during a low gamma-ray state of a FSRQ. For the used model of the BLR, the 95% confidence level on the location of the emission region allows us to place it at a distance > 74% of the outer radius of the BLR. © ESO 2018.The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Exce-lencia “Severo Ochoa” SEV-2012-0234 and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382, and by the Brazilian MCTIC, CNPq and FAPERJ. IA acknowledges support from a Ramón y Cajal grant of the Ministerio de Economía, Industria, y Competitividad (MINECO) of Spain. Acquisition and reduction of the POLAMI and MAPCAT data was supported in part by MINECO through grants AYA2010-14844, AYA2013-40825-P, and AYA2016-80889-P, and by the Regional Government of Andalucía through grant P09-FQM-4784.Peer Reviewe
Detection of the blazar S4 0954+65 at very-high-energy with the MAGIC telescopes during an exceptionally high optical state
The very high energy (VHE ¿ 100 GeV) -ray MAGIC observations of the blazar S4 0954+65, were triggered by an exceptionally high flux state of emission in the optical. This blazar has a disputed redshift of z = 0.368 or z ¿ 0.45 and an uncertain classification among blazar subclasses. The exceptional source state described here makes for an excellent opportunity to understand physical processes in the jet of S4 0954+65 and thus contribute to its classification. Methods. We investigated the multiwavelength (MWL) light curve and spectral energy distribution (SED) of the S4 0954+65 blazar during an enhanced state in February 2015 and have put it in context with possible emission scenarios. We collected photometric data in radio, optical, X-ray, and ¿-ray. We studied both the optical polarization and the inner parsec-scale jet behavior with 43 GHz data. Results. Observations with the MAGIC telescopes led to the first detection of S4 0954+65 at VHE. Simultaneous data with Fermi-LAT at high energy ¿-ray(HE, 100 MeV < E < 100 GeV) also show a period of increased activity. Imaging at 43 GHz reveals the emergence of a new feature in the radio jet in coincidence with the VHE flare. Simultaneous monitoring of the optical polarization angle reveals a rotation of approximately 100. Conclusions. The high emission state during the flare allows us to compile the simultaneous broadband SED and to characterize it in the scope of blazar jet emission models. The broadband spectrum can be modeled with an emission mechanism commonly invoked for flat spectrum radio quasars (FSRQs), that is, inverse Compton scattering on an external soft photon field from the dust torus, also known as external Compton. The light curve and SED phenomenology is consistent with an interpretation of a blob propagating through a helical structured magnetic field and eventually crossing a standing shock in the jet, a scenario typically applied to FSRQs and low-frequency peaked BL Lac objects (LBL). © ESO 2018.The financial support of the German BMBF and MPG, the Italian INFN and INAF, the Swiss National Fund SNF, the ERDF under the Spanish MINECO (FPA2015-69818-P, FPA2012-36668, FPA2015-68378-P, FPA2015-69210-C6-2-R, FPA2015-69210-C6-4-R, FPA2015-69210-C6-6-R, AYA2015-71042-P, AYA2016-76012-C3-1-P, ESP2015-71662-C2-2-P, CSD2009-00064), and the Japanese JSPS and MEXT is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” SEV-2012-0234 and SEV-2015-0548, and Unidad de Excelencia “María de Maeztu” MDM-2014-0369, by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project 13.12.1.3.02, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish National Research Centre grant UMO-2016/22/M/ST9/00382 and by the Brazilian MCTIC, CNPq, and FAPERJ. IA acknowledges support by a Ramón y Cajal grant of the Ministerio de Economía, Industria y Competitividad (MINECO) of Spain. The research at the IAA–CSIC was supported in part by the MINECO through grants AYA2016–80889–P, AYA2013–40825–P, and AYA2010–14844, and by the regional government of Andalucía through grant P09–FQM–4784.Peer Reviewe
Observation of inverse Compton emission from a long γ-ray burst.
Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs
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