Synthesis of vinyl esters of organosilicon carboxylic acids

Conclusions The vinylation of -silicon-containing carboxylic acids by acetylene under the influence of zinc and cadmium salts was investigated. A method was found for producing organosilicon complex vinyl esters.     

Synthesis of γ-diketo carboxylic acids and their esters

Conclusions We have developed a method of obtaining -diketocarboxylic acids and their esters by acid hydrolysis of esters of-(5-methylfuryl)propionic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 214–215, January, 1968.     

Preparation and properties of pure lithio esters of some carboxylic acids

Lithio esters of carboxylic acids have been prepared in pure state and their properties are described. Interaction between the lithio esters with alkali metals alkoxides has been demonstrated, and some adducts have been isolated. The IR and UV spectra of these compounds are described, and their structures are discussed.     

Carbon-13 chemical shifts of some model carboxylic acids and esters

Selected model carboxylic acids and esters dissolved in deuteriochloroform have been studied by carbon-13 nuclear magnetic resonance under standardized conditions. Assignments of the chemical shifts have been made for all samples, and the spin–lattice relaxation times and nuclear Overhauser effects measured for a few selected esters. The results are intended to provide a practical aid for the analysis of carboxylic acids and esters of a more complex nature (e.g. polymers, natural products, etc.).     

Preparation of halo-substituted esters of carboxylic acids

Conclusions The 4-chlorobutyl esters of carboxylic acids were obtained by reacting carboxylic acids with THF in the presence of either SOCl₂ or POCl₃.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1149–1150, May, 1981.     

Synthesis of C-acyl furanosides via the cross-coupling of glycosyl esters with carboxylic acids

C-Acyl furanosides are versatile synthetic precursors to a variety of natural products, nucleoside analogues, and pharmaceutical molecules. This report addresses the unmet challenge in preparing C-acyl furanosides by developing a cross-coupling reaction between glycosyl esters and carboxylic acids. A key step is the photoredox activation of the glycosyl ester, which promotes the homolysis of the strong anomeric C–O bond through CO₂ evolution to afford glycosyl radicals. This method embraces a large scope of furanoses, pyranoses, and carboxylic acids, and is readily applicable to the synthesis of a thymidine analogue and diplobifuranylone B, as well as the late-stage modification of (+)-sclareolide. The convenient preparation of the redox active glycosyl ester from native sugars and the compatibility with common furanoses exemplifies the potential of this method in medicinal chemistry.

A cross-coupling of glycosyl esters with carboxylic acids to prepare C-acyl furanosides and pyranosides. The reaction proceeds through photoredox activation of the glycosyl ester to afford glycosyl radicals.     

Synthesis and antifungal activity of carvacrol and thymol esters with heteroaromatic carboxylic acids

Aiming to obtain the more effective pathogen inhibitive ingredients and explore the influence of introducing different heterocyclic units to carvacrol and thymol esters, twenty ester derivatives with different heterocyclic units were synthesized. And the in vitro antifungal activity of title compounds against five plant pathogenic fungi was evaluated by mycelium growth rate method. The results showed that some carvacrol and thymol esters showed good to excellent antifungal activity, and compound 9d (4-bromo-5-isopropyl-2-methylphenyl picolinate) exhibited a broad antifungal spectrum. Preliminary study indicated that the introduction of furan, thiophene and pyridine unit could enhance the antifungal activity of carvacrol and thymol esters against Botrytis cinerea and a bromine atom on the para position of benzene moiety could enhance their antifungal activity.     

Gas-liquid chromatography of esters of saturated fluorinated carboxylic acids

GLC has been used to determine the contribution of the methylene and difluoromethylene units to the sorption energy of the members of twelve homologous and pseudohomologous series of esters of n-polyfluorinated carboxylic acids for the SE-30 and SKTFT-50Kh stationary phases at 60–160C. An unusual increase in the energy of sorption of the methylene and difluoromethylene units with the increasing mass of the homolog has been observed. It has been found that, in distinction from the contributions of the methylene units, the sorption energy of the difluoromethylene units in the pseudohomologs is higher on the fluorinecontaining phase SKTFT-50Kh than on the nonpolar SE-30 phase, except the first unit. It has been shown that an increase in the temperature of the analysis reduces the energy contributions but that it has no influence on the general character of change of the sorption energy of the ester homologs and pseudohomologs.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 629–634, March, 1991.     

Exotic amino acids. 4. Synthesis of methyl esters of some N-heteroamino-methylenemalonic acids

Isopropylidene N-hetarylaminomethylenemalonates, obtained from isopropylidene ethoxymethylenemalonate and 2-aminopyridine, 2-amino-5-methylpyridine, 2-aminopyrimidine, 7-amino-4-methylcoumarin, and 2-amino-3,5-diethoxycarbonyl-4-methylthiophene, undergo methanolysis at room temperature to give methyl esters of the corresponding N-hetarylaminomalonic acids. Isopropylidene N-hetarylaminomethylenenemalonate, containing a 2-aminothiazole group as a heterocyclic substituent, does not react under analogous conditions, but cyclizes upon heating at reflux to give 5-oxo-5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid. 4-Oxo-9-R-4H-pyridino[1,2-a]pyrimidines are obtained upon the sublimation of isopropylidene N-pyridyl- and N-5-methylpyridylaminomethylenemalonates.Communication 3, see ref. [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 857–860, June, 2000.