Highly Selective Preparation of 3-and 6-Modified Mannose/Altrose Derivatives

A highly efficient method to get 3-and 6-modified mannose/ahrose derivatives for oligosaccharide synthesis is described. All the compounds were obtained exclusively with the combinations of 3-and/or 6-hydroxyl protection and/or activation（ including the configuration conversion of 3-carbon atom）.

Computational studies of the structure and cation-anion interactions in 1-ethyl-3-methylimidazolium lactate ionic liquid

Quantum chemical calculations of the structures and cation-anion interaction of 1-ethyl-3-methylimidazolium lactate ([Emim][LAC]) ion pair at the B3LYP/6-31++G** theoretical level were performed. The relevant geometrical characteristics, energy properties, intermolecular H-bonds (H-bonds), and calculated IR vibrations with respect to isolated ions were systematically discussed. The natural bond orbital (NBO) and atoms in molecule (AIM) analyses were also employed to understand the nature of the interactions between cation and anion. The five most stable geometries were verified by analyzing the relative energies and interaction energies. It was found that the most of the C-H···O intermolecular H-bonds interactions in five stable conformers have some covalent character in nature. The elongation and red shift in IR spectrum of C-H bonds which involve in H-bonds is proved by electron transfers from the lone pairs of the carbonyl O atom of [LAC] to the C-H antibonding orbital of the [Emim]+. The interaction modes are more favorable when the carbonyl O atoms of [LAC] interact with the C2-H of the imidazolium ring and the C-H of the ethyl group through the formation of triple H-bonds.

Microscopic study of binary mixtures between pyrrolidinium bis(triflorosulfonyl)imide and dimethyl sulfoxide/acetonitrile

Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis（triflorosulfonyl）- imide （[BMPyrr][TFSI]） with dimethyl sulfoxide （DMSO） and acetonitrile （AN） have been analyzed in this work. Attenuated total reflection Fourier transform infrared spectroscopy （ATR-FTIR） and density functional theory （DFT） calculations are used in the investigation, while excess infrared spectra and two-dimensional correlation spectroscopy are used to explore the data in detail. It has been found that the molecular solvents can interact with TFSI- （mainly with S=O and weakly with S-N-S group）. AN interacts feebly with BMPyrr＋ as compared with the strong interaction of DMSO. The strength of the interactions depends on the electron donating ability of the solvent. Upon mixing, hydrogen bonds regarding C-Hs in cation and S-N-S in anion are weakened, while that regarding S=O in anion is strengthened. Among the C-Hs which are connected directly with the N of the cation, Cl-H is the main interaction site for both DMSO and AN. This means that Cl-H is the most acidic hydrogen in pyrrolidinium cation.

Inherently Chiral and Symmetrical Heteroatom-Doped Zigzag-Type Hydrocarbon Belts

hydrocarbon belts due to their potential applications in carbon nanotechnology.By contrast,heteroatomembedded zigzag hydrocarbon belts as advanced design strategies with fascinating structures and desirable,unique properties have remained largely unexplored,and inherently chiral ones are unknown.Herein,we report the synthesis of a diversity of symmetric and highly enantiopure inherently chiral O-and N-doped zigzag-type hydrocarbon belts starting from strainless macrocycles based on fjord-stitching strategy.The readily available pertriflated resorcin[6]arene underwent partial hydrolyses and intramolecular S_(N)Ar reactions to form a calix[3](9H-xanthene)derivative and a prochiral half-belt selectively.Straightforward transformations of calix[3](9H-xanthene)into C_(3v)-symmetric molecular belts were achieved by closing the rest of the fjords with triple intramolecular S_(N)Ar reactions and Yamamoto homo coupling reactions,as well as palladiumcatalyzed intermolecular acridination reactions with primary amines.The prochiral half-belt underwent enantioselective desymmetrizative mono-acridination to afford an inherently chiral N,O_(4)-bridged pseudo-belt with an enantiomeric excess(ee)value of>99%under the catalysis of Pd(OAc)_(2)and(R)-Antphos.Ring closure reactions of the pseudo-belt produced diverse heteroatom-inlayed zigzag-type hydrocarbon belts of inherent chirality.Further,we showed the unique cavity structures of the belts and demonstrated interesting chiroptic properties of the inherently enantiopure chiral belts.This research opens the door for the exploration of novel and sophisticated symmetric and inherently chiral molecular nanobelt structures with outstanding physical and chemical properties,as well as potential applications.

Low-melting mixture solvents:extension of deep eutectic solvents and ionic liquids for broadening green solvents and green chemistry

Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.

Targeting toll-like receptor 7 as a therapeutic development strategy for systemic lupus erythematosus

Endosomal TLRs(TLR3/7/8/9)are highly analogous innate immunity sensors for various viral or bacterial RNA/DNA molecular patterns.Among them,TLR7,in particular,has been suggested to be a target for various inflammatory disorders and autoimmune diseases including systemic lupus erythematosus(SLE);but few small-molecule inhibitors with elaborated mechanism have been reported in literature.Here,we reported a well-characterized human TLR7-specific small-molecule inhibitor,TH-407b,with promising potency and negligible cytotoxicity through a novel binding mechanism.Notably,TH-407b not only effectively inhibited TLR7-mediated pro-inflammatory signaling in a variety of cultured cell lines but also demonstrated potent inflammation suppressing activities in primary peripheral blood mononuclear cells(PBMCs)derived from SLE patients.Furthermore,TH-407b showed prominent efficacy in vivo,improved survival rate and ameliorated symptoms of SLE model mice.To obtain molecular insights into the TH-407b derivatives’inhibition mechanism,we performed the structural analysis of TLR7/TH-407b complex using cryogenic electron microscopy(cryo-EM)method.As an atomistic resolution cryo-EM structure of the TLR family,it not only of value to facilitate structure-based drug design,but also shed light to methodology development of small proteins using EM.Significantly,TH-407b has unveiled an inhibition strategy for TLR7 via stabilizing its resting/inactivated state.Such a resting state could be generally applicable to all TLRs,rendering a useful method for targeting this group of important immunological receptors.

Highly enantioselective carbene-catalyzedδ-lactonization via radical relay cross-coupling

An N-heterocyclic carbene(NHC)catalyzed enantioselective cyclisation and trifluoromethylation of olefins with cinnamaldehydes via radical relay cross-coupling in the presence of Togni reagent is reported andδ-lactones tolerated with stereogenic centers atβ-andγ-positions are obtained in moderate to high yields and with high enantioselectivities.Further computational studies explain that the radical crosscoupling step is the key to determining the enantioselectivity.Energy analysis of key transition states and intermediates also provides a reasonable explanation for the difficulty of diastereoselective control.DFT calculations also reveal that the hydrogen-bonding interaction plays a vital role in the promotion of this chemistry.