The synthesis of nine new, bifunctional organocatalysts having carbohydrate scaffolds has been accomplished. In these catalysts both of the catalytic amino and thiourea functions are directly attached to a carbohydrate core. The activities of the newly prepared catalysts were tested in a Michael addition.
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http://dx.doi.org/10.1016/j.carres.2013.12.026 | DOI Listing |
RSC Adv
May 2024
Department of Pharmaceutical Sciences, Università del Piemonte Orientale Largo Donegani 2 28100 Novara Italy
Asymmetric epoxidation represents a hot topic in organic synthesis. In recent years, organocatalysts based on sugar skeletons have been exploited in asymmetric epoxidation to achieve enantiomeric pure epoxides. In this work, two different endocyclic ketones derived from glucose and galactose protected with a 4,6--benzylidene group have been prepared and exploited for Shi-type epoxidation.
View Article and Find Full Text PDFACS Omega
September 2023
Department of Chemistry, National Institute of Technology Karnataka (NITK), Surathkal, Mangalore,575025Karnataka ,India.
The Biginelli reaction provides 3,4-dihydropyrimidin-2(1)-ones (DHPMs), whereas the Hantzsch reaction leads to 1,4-dihydropyridines (DHPs) by the one-pot, multicomponent, and operationally simple transformations starting from readily available starting materials. DHPMs and DHPs are well-established heterocyclic moieties in the synthetic organic chemistry literature and have pronounced pharmacological activities. This work reports the synthesis of novel DHPMs and DHPs from carbohydrate-derived 5-substituted-2-furaldehydes by employing gluconic acid aqueous solution (GAAS) as an efficient, inexpensive, and eco-friendly catalyst.
View Article and Find Full Text PDFChemistry
October 2023
Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
A novel organocatalyzed [3+2] cycloaddition reaction of nitroolefins with glycosyl azides as well as organic azides has been developed for successful construction of 1,5-disubstituted triazolyl glycoconjugates. This metal-free and acid-free, regioselective synthetic protocol proceeds in the presence of only Schreiner thiourea organocatalysts, which enable the required activation of nitroolefins through double hydrogen bonding. The straightforward, operationally simple, and regioselectivity of this methodology, complementing to the classical RuAAC catalyzed synthesis of 1,5-disubstituted 1,2,3-triazoles.
View Article and Find Full Text PDFJ Am Chem Soc
July 2023
Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.
A key challenge in origin-of-life research is the identification of plausible conditions that facilitate multiple steps along the pathway from chemistry to biology. The incompatibility of nucleotide activation chemistry and nonenzymatic template-directed RNA copying has hindered attempts to define such a pathway. Here, we show that adding heteroaromatic small molecules to the reaction network facilitates in situ nucleotide phosphate activation under conditions compatible with RNA copying, allowing both reactions to take place in the same mixture.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
July 2023
Institute for Chemical Research, Kyoto University.
A strategy for symmetric synthesis based on dynamic chirality of enolates (memory of chirality) has been developed. Asymmetric alkylation, conjugate addition, aldol reaction, and arylation via C-N axially chiral enolate intermediates are described. Asymmetric alkylation and conjugate addition via C-O axially chiral enolate intermediates with a half-life of racemization as short as approx.
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