Photocaging of Carboxylic Function Bearing Biomolecules by New Thiazole Derived Fluorophore.

The design and synthesis of a new fluorophore containing an arylidene thiazole scaffold resulted in a compound with good photophysical characteristics. Furthermore, the thiazole C5-methyl group was easily modified into specific functional groups (CH2 Br and CH2 OH) for the formation of a series of photocourier molecules containing model compounds (benzoic acids), as well as prodrugs, including salicylic acid, caffeic acid, and chlorambucil via a "benzyl" linker. Spectral characteristics (1 H, 13 C NMR, and high-resolution mass spectra) corresponded to the proposed structures. The photocourier molecules demonstrated absorption with high values of coefficient of molar extinction, exhibited contrasting green emission, and showed good dark stability. The mechanism of the photorelease was investigated through spectral analysis, HPLC-HRMS, and supported by TD-DFT calculations. The photoheterolysis and elimination of carboxylic acids were proved to occur in the excited state, yielding a carbocation as an intermediate moiety. The fluorophore structure provided stability to the carbocation through the delocalization of the positive charge via resonance structures. Viability assessment of Vero cells using the MTT-test confirmed the weak cytotoxicity of prodrugs without irradiation and it increase upon UV-light.

Thioisomünchnones versus Acrylamides via Copper-Catalyzed Reaction of Thioamides with Diazocarbonyl Compounds.

A novel carbenoid-mediated approach to thioisomünchnones was developed by intermolecular copper-catalyzed reactions of diazoacetamides with aromatic and heteroaromatic thioamides bearing a pyrrolidine moiety. The direction of the reaction can be switched toward 2-amino-2-heteroarylacrylamides by replacing the pyrrolidine with an aniline group or by the use of 2-cyano-2-diazoacetamides. The proposed mechanism and DFT calculations allowed us to rationalize the effect of substituents on the reaction direction. Effective methods were found for the synthesis of previously unknown both 2-heteroarylthioisomünchones and 2-heteroarylacrylamides, based on a wide scope of available reagents with a similar structure. Some of the synthesized thioisomünchnones exhibited multicolor fluorescence in the solid state and solutions.

Two Approaches for the Synthesis of Fused Dihydropyridines via a 1,6-Electrocyclic Reaction: Fluorescent Properties and Prospects for Application.

Reactions of penta-2,4-dienethioamides with acetylenedicarboxylic acid, methyl and ethyl esters, and methyl propiolate were systematically studied, and a number of new 2,3-dihydro-5H-thiazolo[3,2-a]pyridines (DTPs) and 4H,6H-pyrido[2,1-b][1,3]thiazines (PTZs) were prepared. A possible mechanism for a multistep domino transformation is suggested, and the key step is the 1,6-electrocyclic reaction. An additional alternative method for the synthesis of new heterocyclic systems was achieved. Evidence of the electrocyclic mechanism of a key step was collected from the analysis of the spatial structure of the synthesized bicyclic nonaromatic pyridines by X-ray diffraction and quantum chemical calculations, as well as from the thermodynamic quantities. DTPs exhibited yellow fluorescence in solution and yellow to red emissions in the solid state. Biological investigations demonstrated the ability of DTPs to penetrate living and fixed cells and presumably accumulate in lysosomes.

The bank of biological samples representing individuals exposed to long-term ionizing radiation at various doses.

Collection and storage of biological specimens in biobanks aims to obtain and preserve samples of different kinds for biological and medical studies. Here we present a description of the Bank of Biological Materials (BBM) housed by the Seversk Biophysical Research Centre (SBRC; Seversk, Russia). The main goal of maintaining the BBM is to collect and store biological samples suitable for genetic studies of people exposed to long-term ionizing radiation. Currently, the collection includes 19,194 biological specimens obtained from 8105 donors, of whom 42.3% are diagnosed with malignant neoplasms, 28.7% are healthy residents of the city of Seversk, 18.8% are healthy employees of the Siberian Group of Chemical Enterprises (SGCE), and 10.2% are patients diagnosed with acute myocardial infarction. The donors were enrolled using the Regional Medical and Dosimetric Register database created by the SBRC. For each donor, DNA specimens were extracted from peripheral blood and tissues and cell suspensions for cytogenetic analysis were prepared routinely. The BBM's unique collection is suitable primarily for studies of individual radiosensitivity of humans (IRH), and genetic aspects of the pathophysiology of common human diseases, especially in populations exposed to long-term low-dose ionizing radiation.