Thermosensitive hydrogels are very important biomaterials used in drug delivery systems (DDSs), which gained increasing attention of researchers. have great potential various applications, such as delivery, cell encapsulation, tissue engineering, and etc. Especially, injectable thermosensitive with lower sol-gel transition temperature around physiological been extensively studied. By vivo injection, the formed non-flowing gel at body temperature. Upon incorporation pharmaceutical agents,...

Smart hydrogels that undergo structural changes in response to stimuli (for example, pH, heat, light) have promising biomedical applications as delivery systems, especially for the locally controlled release of drugs. Early prevention locoregional recurrence (LRR) is critical patients who undergone breast-conserving therapy. This work reports preparation a hybrid hydrogel system which gold nanorods (GNRs) were doped into thermally responsive hydrogel. A near-infrared (NIR) laser was used...

The performance of DMSO for the dehydration fructose to 5-hydroxymethylfurfural (HMF) in presence and absence Brønsted acid has been theoretically investigated at G4 level solution. most stable form is β-D-fructofuranoses When present reaction system, H+ prefers interact with other than fructose, forming [DMSOH]+ as catalytically active species. For HMF, catalytic stems from valence unsaturation both S O atoms unsaturated double bond S═O, role originates atoms, well H-mediated effect −SOH...

This review provides an overview of the palladium-catalysed diverse cyclisations VECs over past five years, which could offer powerful synthetic tools to access various functionalised heterocycles.

An acylative Suzuki-type cross-coupling of alkyl trifluoroborates and acid fluorides was developed by merging NHC organocatalysis with photoredox catalysis. A broad spectrum ketones could be facilely synthesised under mild reaction conditions.

Abstract The direct functionalization of inert C(sp 3 )−H bonds under environmentally benign catalytic conditions remains a challenging task in synthetic chemistry. Here, we report an organocatalytic remote acylation amides and cascade cyclization through radical‐mediated 1,5‐hydrogen atom transfer mechanism using N‐heterocyclic carbene as the catalyst. Notably, diversity nitrogen‐containing substrates, including simple linear aliphatic carbamates ortho ‐alkyl benzamides, can be successfully...

Oxidative N-heterocyclic carbene (NHC) organocatalysis, typically leading to the formation of acyl azolium reactive intermediates, constitutes one most important activation strategies for NHC-catalyzed chemical transformations. Here, we report an unprecedented oxidative radical NHC catalysis by using peroxyester as external single-electron oxidant realize divergent difunctionalization olefins. The key success this chemistry is catalytic generation oxygen radicals that could trigger...

An N-heterocyclic carbene organocatalytic 1,4-difunctionalization of 1,3-enynes was developed. This strategy suitable for a broad spectrum substrates to efficiently synthesize allenic ketones bearing diverse substituents. Preliminary mechanistic studies suggest radical reaction pathway this acylalkylation process.

The divergent construction of chiral medium-sized rings is an essential but challenging task in organic synthesis. Herein, we report a temperature-controlled catalytic system for the divergent, enantioselective synthesis different types starting from same substrate set. Enabled by planar bisphosphine ligand, palladium-catalyzed (5 + 4) and formal 2) annulations cyclic aza-dienes vinylethylene carbonates proceeded smoothly to afford broad spectrum indole-based heterocycles excellent yields...

Abstract Little is known about the molecular pathway to monomers of semiconductor nanocrystals. Here we report a general reaction pathway, which based on hydrogen-mediated ligand loss for precursor conversion ‘monomers’ at low temperature before nucleation. We apply 31 P nuclear magnetic resonance spectroscopy monitor key phosphorous-containing products that evolve from MX n + E =PPh 2 H+H Y mixtures, where , H, and H are metal precursors, chalcogenide additives, respectively. Surprisingly,...

The diversity of spirocyclic architecture offers a vast chemical space and enormous potential for drug discovery, while the skeletal diversity-oriented synthesis spiromolecules from simple starting materials remains challenging task. Here, we report divergent stereoselective construction [5,5] [5,6] spiroheterocycles identical substrates (vinylethylene carbonates pyrrolidone-derived enones) through Lewis-acid-assisted Brønsted-base-assisted palladium catalysis, respectively. With this...

Abstract Radical N ‐heterocyclic carbene (NHC) organocatalysis has progressed significantly in recent years, enabling various incredible transformations. However, prefunctionalized substrates bearing a redox functionality were always required. As result, the direct functionalization of aliphatic C−H bonds simple remains challenge. This situation was changed once hydrogen transfer atom (HAT) strategy successfully applied radical NHC catalysis very recently. concept paper focused on discussion...

Developing diversity-oriented synthetic approaches for medium-sized rings is of great interest, and the divergent synthesis with different ring sizes poses a challenging task. In this study, we present catalyst-controlled switchable (5 + 4)/(3 4) cycloaddition strategy seven- nine-membered heterocycles. Utilizing two 4-aminopyridine Lewis base catalysts, pyrazole-fused benzazepines or benzoxazonines can be efficiently assembled from same substrates. These products exhibit good stability...

Oxindoles and β-lactams are attractive structural motifs because of their unique biological importance. However, the fusion two moieties featuring 3,3′-spirocyclic scaffolds is a challenging task in organic synthesis. Herein we designed novel type oxindole-based azaoxyallyl cation synthons, which could readily participate [3 + 1] cyclization with sulfur ylides. With this protocol, collection 3,3-spiro[β-lactam]-oxindoles were facilely produced up to 94% yield perfect diastereoselectivity.

Abstract Since 3-acetylamino-5-acetylfuran (3A5AF) has been regarded as a promising nitrogen-containing synthon, the conversion of renewable chitin and its monomer N-acetyl-D-glucosamine (NAG) to 3A5AF is significance. In this paper, we compared catalytic activity several Cl-containing compounds found that LiCl exhibited superior performance. The effects solvent, catalyst dosage, reaction temperature, time on synthesis were investigated. Under optimized conditions, about 60% yields obtained...

Metallocenes with planar and central chirality have emerged as a privileged skeleton for chiral ligand design, such ligands exhibited tremendous success in various asymmetric catalysis protocols. Herein, we report rhodium/chiral diene-catalyzed desymmetrization of 1,2-diformylmetallocenes aryl/alkenylboronic acids to give enantio-enriched formylmetallocenes, which are diastereoisomers Ugi-type products. This catalytic system also enables the kinetic resolution 2-substituted 1-formylferrocene...

The mechanism of glucose-to-fructose isomerization, as one the key intermediate steps in biomass valorization, remains an intriguing topic potential chemo-catalysis. In present work, catalytic isomerization AlCl3 aqueous solution has been theoretically investigated at PBE0/6-311++G(d,p), aug-cc-pvtz level. activities possible active species from hydrolysis solution, that is, Lewis acids ([Al(OH)(H2O)4]2+ and/or [Al(OH)2(H2O)2]+) and Brønsted acid (H3O+) together with counterpart anion Cl–,...

A novel sulfonated organocatalyst bearing stable double H-bonds shows high catalytic performance and good reusability for the tandem production of 5-ethoxymethylfurfural (EMF), a biofuel candidate, from biomass-derived fructose.

It is still not clear at the molecular level how acidic silanol and basic alkylamine bifunctional groups over SBA-15 zeolite exert catalytic functions in aldol condensation of 5-hydroxymethylfurfural (HMF) with acetone, which plays pivotal roles synthesis renewable fuels from biomass. Here, mechanisms (1) acetone to produce 4-[5-(hydroxymethyl)-2-furanyl]-3-buten-2-one (C9H10O3) [−SiOH], [−RNH2], cooperative acidic–basic [−SiOH/–RNH2] active sites on alkylamine-grafted (SBA-15–RNH2) have...

Abstract Heteroaromatic N ‐oxides, renowned for their highly polar N─O bond and robust structure, exhibit significant bioactivities have played a pivotal role in various drug development projects since the discovery of Minoxidil. Moreover, heteroaromatic featuring axially chiral biaryl frameworks, are indispensable as Lewis base catalysts ligands organic synthesis. Despite importance, synthesizing these compounds is challenging, necessitating starting materials or resolution processes....

In the V-doped Al-MCM-41 framework, <bold>[V-1]</bold> active site with a hydroxyl group displays better catalytic activity than <bold>[V-0]</bold> without toward oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran.

The fundamental understanding of the cooperativity a Brønsted acid together with its anion for cellulose conversion in an aqueous solution is limited at present, which cellobiose has usually been regarded as bridge that connects monosaccharides and cellulose. mechanism β-cellobiose to 5-hydroxymethylfurfural (HMF) catalyzed by (H3O+) accompanied counteranions studied using quantum chemical calculations M06-2X/6-311++G(d,p) level under polarized continuum model (PCM-SMD). For formation first...