Synthesis of Silicon and Germanium Containing Heteroaromatic Sulfides as Cholesterol Level Lowering and Vasodilating Agents

Silicon and germanium containing heteroaromatic sulfides have been prepared using phase transfer catalytic (PTC) system thiol / Si or Ge containing alkyl halide / solid KOH / 18- crown-6 / toluene. The target sulfides were isolated in yields up to 92 %. It has been found that 2-{[dimethyl (β-triethylgermylethyl)-silylmethyl]thio}-1-methylimidazole and 2-{[dimethyl(β-triphenylsilylethyl) silyl-methyl]thio}benzothiazole are the most active cholesterol level lowering and vasodilating agents

Synthesis and Cytotoxicity of Silicon and Germanium Containing Pyridine Oxime O-Ethers

Silicon and germanium containing pyridine aldoxime, ketoxime and amidoxime O-ethers have been prepared using phase transfer catalytic systems oxime alkyl halide solid KOH 18-crown-6 benzene and oxime alkyl halide solid K2CO3 or Cs2CO3 18-crown-6 toluene. Cytotoxic activity of silicon and germanium containing pyridine oxime O-ethers was tested in vitro on two monolayer tumor cell lines: MG- 22A (mouse hepatoma) and HT-1080 (human fibrosarcoma). O-[3-Yriethylsilylpropyl]- and O-[3-(1-methyl- 1-silacyclopentyl)propyl] oximes of pyridine aldehydes and ketones exhibit high cytotoxicity. Presence of methyl group in the pyridine ring considerably decreased activity of amidoxime O-ethers. Oxime ethers containing two elements are essentially inactive. For 2-acetylpyridine oxime ethers the activity increases in order of alkyl substituents: Et3GeCH2CH2SiMe2CH2 < Et3SiCH2CH2CH2 < (CH2)4SiCH2CH2CH2. Cytotoxicity of ketoxime O-ethers is considerably lower in comparison with aldoxime O-ethers

Silacyclic Derivatives of Heteroaromatic Sulfides as Selective Cholesterol Level Lowering and Vasodilating Agents

Silacyclic derivatives of heteroaromatic sulfides have been prepared by using phase transfer catalytic (PTC) system thiol / silacyclopropyl iodide / solid K2CO3 / 18-crown-6 / toluene. The target sulfides were isolated in yields up to 70 %. The S-derivatives of N-methylimidazolyl, benzoxazolyl and 1,3,4-triazolyl thiols selectively lowered the low density lipoprotein (LDL) level in mice with the high cholesterol diet in nutrition

Synthesis and Cytotoxicity of Silicon and Germanium Containing Pyridine Oxime O-Ethers

ABSTRAC

ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients

Arenu un hetarenu acil-, alkenil- un alkinilatvasinajumu nukleofilas aizvietosanas, halogenesanas un ciklopievienosanas reakcijas starpfazu katalizes apstaklos

The main goal of the work was to develop new, convenient and simple phase transfer catalytic methods for the synthesis of aromatic and heteroaromatic compounds. It contains Introduction (Chapter 1), Description of work (Chapters 2-8), Conclusions and list of publications. It was shown that PTC alkylation of methyl ketones was an excellent method for the synthesis of sterically hindered ketones (Chapter 2). Using the phase transfer catalytic method the synthesis of C-dialkylated and C-trialkylated ketones was undertaken. A wide range of synthetical possibilities for the reactions of carbanions and anions of aromatic and heteroaromatic compounds with perhaloalkanes was shown (Chapter 3). The syntheses of a novel classes of biologically active compounds such as O-(halopropargyl)oximes and 2-hetaryl-2-trichloromethyloxiranes were developed. The reactions of dichlorocarbene and dibromocarbene with different aromatic and heteroaromatic substances were demonstrated (Chapter 4). Chapter 5 of present work described simple, mild and convenient methods for the synthesis of aromatic and heteroaromatic O- and S-ethers. Using phase transfer catalysis novel methods for the synthesis of silicon containing ketoxime O-ethers and pyridine sulfides were developed. It was demonstrated that fluoride ion was excellent activator of silicon bonds in different silanes (dimethylphenylsilane, trimethylcyanosilane, trimethylsilylacetylene, etc.) (Chapter 6). The synthesis of optically active aromatic and heteroaromatic alcohols from the corresponding carbonyl compounds in water in the presence of #beta#-cyclodextrin as a reverse phase transfer catalyst was carried out (Chapter 7). It was found that betaines derived from amino and hydrazino acids catalyze the phase transfer reactions (Chapter 8). In the majority of cases the activity of betaines was at least similar to that of typical phase transfer catalystsSeparate summaries in Latvian, EnglishAvailable from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi

SYNTHESIS OF NOVEL BICYCLIC AND TRICYCLIC THIAZOLE AND IMIDAZOLE CONTAINING 2-AMINOPROPIONIC ACIDS

Abstract: Synthesis of four novel bicyclic and tricyclic amino acids (2-amino-3-benzo Keywords: 2-amino-3-benzo Introduction Amino acid derivatives are of interest because of wide range of biological activity. Beside this amino acid derivatives are widely used as substrates in the organic synthesis 1 . Among natural heterocyclic 2-aminopropionic acids histidine (thus, imidazole containing amino acid) was widely applied in organic synthesis because of biological importance 2-12 . Some works were dedicated to investigation of synthesis and reactions of thiazole containing 2-aminpropionic aci