Search results for "Acetals"
showing 6 items of 6 documents
A Vastly Increased Chemical Variety of RNA Modifications Containing a Thioacetal Structure
2018
International audience; Recently discovered new chemical entities in RNA modifications have involved surprising functional groups that enlarge the chemical space of RNA. Using LC-MS, we found over 100 signals of RNA constituents that contained a ribose moiety in tRNAs from E. coli. Feeding experiments with variegated stable isotope labeled compounds identified 37 compounds that are new structures of RNA modifications. One structure was elucidated by deuterium exchange and high-resolution mass spectrometry. The structure of msms2 i6 A (2-methylthiomethylenethio-N6-isopentenyl-adenosine) was confirmed by methione-D3 feeding experiments and by synthesis of the nucleobase. The msms2 i6 A contai…
Synthesis of the aggregation pheromone of the Colorado potato beetle from its degradation product
2015
Incubation of the Colorado potato beetle aggregation pheromone, (S)-1,3-dihydroxy-3,7-dimethyl-6-octen-2-one, with antennal or leg extracts from this beetle gave 6-methyl-5-hepten-2-one as the major product. This ketone was used as a substrate in a stereoselective synthesis of the pheromone. It was attached to the butanediacetal of glycolic acid with good stereoselectivity and the desired isomer was further enriched by purification of the product of this reaction on silica gel.
CuCl catalyzed radical cyclisation of N-alpha-perchloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides
2012
The discovery that cycloalkanes can form thermomorphic systems with typical polar organic solvents has led to the development of less-polar electrolyte solutions. Their mixing and separation can be regulated reversibly at a moderate temperature range. The phase switching temperature can be controlled by changing the solvent compositions. While biphasic conditions are maintained below the phase switching temperature, conductive monophasic conditions as less-polar electrolyte solutions are obtained above the phase switching temperature. After the electrochemical transformations, biphasic conditions are reconstructed below the phase switching temperature, facilitating the separation of cycloal…
Selective isomerization of a trans -butanediacetal derivative of tartaric acid with differentiating substituents at C-2 and C-3
2017
Abstract A trans-disubstituted butanediacetal derivative with two different substituents (ester and thioester) – methyl (2R,3R,5R,6R)-3-ethylsulfanylcarbonyl-5,6-dimethoxy-5,6-dimethyl-1,4-dioxane-2-carboxylate, was selectively converted to the cis derivative – methyl (2S,3R,5R,6R)-3-ethylsulfanylcarbonyl-5,6-dimethoxy-5,6-dimethyl-1,4-dioxane-2-carboxylate in high yield on a multigram scale. The product of this reaction offers the possibility for selective modification of one of the substituents, which was demonstrated by Fukuyama reduction of the thioester group.
A DFT study of the molecular mechanisms of the nucleophilic addition of ester-derived lithium enolates and silyl ketene acetals to nitrones: Effects …
2006
9 pages, 6 schemes, 3 figures, 2 tables.
DES-polyacetals as polymer therapeutics for the treatment of prostate cancer
2012
Esta tesis se centra en el diseño de nuevos conjugados polímero-fármaco sensibles a pH para usarse como agentes únicos o en terapia de combinación para el tratamiento del cáncer hormono-dependiente, en particular cáncer de próstata. Éstos conjugados se basan en sístemas poliacetalicos previamente descritos en los que el fármaco forma parte de la cadena principal del polímero. En el microambiente tumoral o después de la absorción celular por endocitosis, el descenso del pH encontrado en el compartimiento ácido del endosoma lisosomal, desencadena la degradación del polímero y como consecuencia la liberación del fármaco que se difunde fuera en el citosol. Para el diseño de éstos sistemas, la n…