نتایج جستجو برای: dbu

تعداد نتایج: 315  

Journal: :Chemical communications 2005
Julie E Murtagh Séamus H McCooey Stephen J Connon

Substoichiometric loadings of DBU catalyse the efficient 1,4-addition of alcohols and non-nucleophilic amines such as pyrrole to activated alkenes; the application of this methodology in a one-pot synthesis of a natural product, and as a novel strategy for the synthesis of mono-protected 1,3-carbonyl compounds is reported.

Journal: :Chemical communications 2012
Wei Wei Xiao-Yu Hu Xiao-Wei Yan Qiang Zhang Ming Cheng Jian-Xin Ji

The first transition-metal-catalyzed direct oxidative synthesis of amides by using dioxygen as an oxygen source has been developed under mild conditions, in which DBU was used as the key additive. The present methodology, which utilizes dioxygen as an oxidant and oxygen source and cheap copper salts as catalysts, opens up an interesting and attractive avenue for the synthesis of amide functiona...

Journal: :SIAM Journal on Matrix Analysis and Applications 2023

Given a nonnegative matrix factorization, , and factorization rank, exact (exact NMF) decomposes as the product of two matrices, with columns, such . A central research topic in literature is conditions under which decomposition unique/identifiable up to trivial ambiguities. In this paper, we focus on partial identifiability, that is, uniqueness subset columns We start our investigations data‐b...

Journal: :Organic & biomolecular chemistry 2013
Honglai Jiang Hongming Jin Ablimit Abdukader Aijun Lin Yixiang Cheng Chengjian Zhu

Organocatalyst and metal provide different products: a catalyst-controlled switchable phosphination of α-diazoesters has been developed by using DBU and copper as catalysts. It provided an efficient synthetic method for the construction of various phosphorus compounds via the formation of N-P and C-P bonds.

Journal: :Chemical communications 2013
Shoko Hachiya Yoshio Kasashima Fumitoshi Yagishita Takashi Mino Hyuma Masu Masami Sakamoto

Optically active materials could be generated by simple solidification of achiral materials without an external chiral source. When achiral cis-3,4-diphenylsuccinimides were solidified in the presence of a catalytic amount of DBU by evaporating the solvent with stirring, optically active trans-3,4-diphenylsuccinimides were obtained quantitatively with high enantiomeric excesses.

Journal: :Journal of the Turkish Chemical Society, Section A: Chemistry 2023

A facile preparation of polystyrene-block-poly(lactide-co-glycolide) PS-b-PLGA block copolymers was reported in detail. Well-defined were successfully obtained via living anionic polymerization and ring-opening polymerization. First, hydroxyl-terminated linear polystyrenes prepared by The resulting polymers used as macroinitiators for copolymerization lactide glycolide the presence 1,8-diazabic...

Journal: :American journal of physiology. Heart and circulatory physiology 2008
L S A Capettini S F Cortes M A Gomes G A B Silva J L Pesquero M J Lopes M M Teixeira V S Lemos

Endothelium-dependent vasorelaxation in large vessels is mainly attributed to Nomega-nitro-L-arginine methyl ester (L-NAME)-sensitive endothelial nitric oxide (NO) synthase (eNOS)-derived NO production. Endothelium-derived hyperpolarizing factor (EDHF) is the component of endothelium-dependent relaxations that resists full blockade of NO synthases (NOS) and cyclooxygenases. H2O2 has been propos...

Journal: :Organic letters 2013
Bandi Ramakrishna Perali Ramu Sridhar

Electrophilic ring opening of spiro-cyclopropanecarboxylated sugars followed by reaction with DBU revealed interesting ring-contraction and ring-expansion reactions depending on the substrate and the kind of hydroxyl protective group present adjacent to the spiro center. A stereoselective method for accessing a new class of carbon chain extended keto-furanoses and C-glycosylated bicyclic compou...

Journal: :Nucleic acids research 1991
W J Stec A Grajkowski M Koziolkiewicz B Uznanski

The synthesis and separation of diastereoisomerically pure 5'-O-DMT-nucleoside 3'-O-(2-thio-1,3,2-oxathiaphospholane) allows their use as synthons in DBU-catalyzed reaction with the 5'-hydroxyl function of solid-support-bound nucleoside moiety. Since this reaction is stereospecific (greater than 99%), this novel method allows preparation of oligo(nucleoside phosphorothioates) with predetermined...

Journal: :Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology 2017
Kaho Suzuki Kairi Yamato Ryo Sekiya Takeharu Haino

Edge-modified graphene quantum dots (GQD-1) showed base-dependent photoluminescence (PL) responses. DBN, DBU, and Et3N gradually enhanced the PL intensity and then caused quenching, whereas quenching was not observed when pyridine and pyrimidine were used. The quenching can be explained by the photoinduced electron transfer from the anchored bases at the periphery to the emissive sites of GQD-1.

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