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The solvation of sugars in aqueous media matters in the understanding of biological systems and carbohydrate transformations. The presence of NaCl is known to perturb hydrogen bonding of sugar hydrates, however, direct evidence to elucidate mechanism at atom level is very rare even though the "NaCl Effect" was well known in biomass transformations for chemicals/biofuels. Here we report experimental evidences of a clear staircase‐like correlation between induced 1H NMR changes of D‐glucose/fructose with concentration of NaCl aqueous solution at room temperature; and two stable bonding status was observed in the system. HDO in sugar/NaCl aqueous solution as a "dynamic" reference is a key to enable decoupling the global salt effect in this 1H NMR investigation of NaCl‐saccharide interaction. Via a further half‐quantitative study, three structures of stable sugar‐NaCl‐water complexes were mapped for the first time in tackling the NaCl‐monosaccharide interaction at atomic level in an aqueous solution. Based on the maximum of induced 1H NMR shifts, an ideal NaCl usage was proposed. [ABSTRACT FROM AUTHOR]

Anomerization of glycosides was rarely performed under basic condition. Here, an imidazole promoted anomerization of β‐D‐glucose pentaacetate in solid state at room temperature was discovered. This unprecedent anomerization occurred after simple premixing and reaction proceeded continuously in solid state to full conversion without stirring or mechanomixing. Full conversion of all β‐forms in the mixture (α:β=2.2 : 1) into α‐forms only was demonstrated at 1 gram scale. A proposed mechanism involved with inter/intramolecular acyl transfer promoted by imidazoles in a concerted manner may promote the discovery of more new transformations in solid state. [ABSTRACT FROM AUTHOR]

Caulerpin was economically synthesized with a new easy‐handled procedure in higher overall yield of 25.4%, compared to overall yield of 11% in reported literature. Evaluation of caulerpin in new types of cancer cell lines was performed and generally excellent biological activities were observed. In which, caulerpin showed the most activity in human liver tumor cell line (Huh7: IC50 =0.7 μM). Caulerpin was economically synthesized with a new easy‐handled procedure in higher overall yield. Evaluation of caulerpin in new types of cancer cell lines was performed and generally excellent biological activities were observed. In which, caulerpin showed the most activity in human liver tumor cell line (Huh7: IC50 =0.7 μM). [ABSTRACT FROM AUTHOR]

A new class of PEGylation quaternary (triphenyl‐) phosphonium tosylate (PQPT) was synthesized with different length of polyethylene glycol chain; the procedure is chromatography‐free and practical for large scale synthesis. All PQPTs are soluble in water and showed good anti‐bacterial activity. Particularly, cytotoxicity study on NIH 3T3 cell lines indicated PQPT with PEG750 does not inhibit cell proliferation even at relatively high concentration of 6 mg/ml. The observed excellent binding ability of quaternary (triphenyl‐) phosphonium centre with drug Fluorouracil and the low cytotoxicity in healthy cell lines make PQPTs promising candidates as carriers for drug/gene delivery targeting cells' mitochondria. PEGylation quaternary (triphenyl‐) phosphonium tosylate (PQPT) with different length of polyethylene glycol chain was synthesized in a chromatography‐free manner. The observed excellent binding ability of quaternary (triphenyl‐) phosphonium centre with drug Fluorouracil and the low cytotoxicity to healthy cell lines make PQPTs promising candidates as carriers for drug/gene delivery. [ABSTRACT FROM AUTHOR]

Photoluminescent behaviours of chitosan were investigated. Photoluminescence can be observed from aqueous solution of chitosan, and CO[sub 2] treatment can improve the intensity of photoluminescence. The maximum emission is obtained with an excitation at ~336 nm, and the emission wavelength is dependent on the excitation wavelength with a longer excitation wavelength leading to a longer emission wavelength. The chemistry of chitosan before and after CO[sub 2] treatment was characterised; and the results reflect that carbamato anion is formed via the reaction between the amines and CO[sub 2], and is the fluorophore of the photoluminescence observed. Furthermore, chitosan was applied as an imaging agent for imaging MCF-7 cells using confocal microscopy. Blue and bright green imaging of the cells can be obtained via tuning the excitation and emission wavelength. Together with a low cytotoxicity reflected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide evaluation, fluorescent chitosan is promising for bio-imaging. [ABSTRACT FROM AUTHOR]

The production of bulk chemicals and fuels from renewable biobased feedstocks is of significant importance for the sustainability of human society. The production of ethanol from biomass has dramatically increased and bioethanol also holds considerable potential as a versatile building block for the chemical industry. Herein, we report a highly selective process for the conversion of ethanol to C4 bulk chemicals, such as 2,3- butanediol and butene, via a vitamin B1 (thiamine)-derived Nheterocyclic carbene (NHC)-catalyzed acetoin condensation as the key step to assemble two C2 acetaldehydes into a C4 product. The environmentally benign and cheap natural catalyst vitamin B1 demonstrates high selectivity (99%), high efficiency (97% yield), and high tolerance toward ethanol and water impurities in the acetoin reaction. The results enable a novel and efficient process for ethanol upgrading. [ABSTRACT FROM AUTHOR]

A polydisulfide MRI contrast agent was obtained by grafting diethylenetriaminepentaacetic (DTPA) to disulfide-containing poly(amido amine)s-graft-poly(ethylene glycol) (PEG) followed by Gd(III) complexation. Self-assembly of the MRI contrast agent obtained occurs in aqueous solution forming nanosized micelles with PEG shells and ionic complex cores. The chemistry and structures of the MRI contrast agent and assembly were characterized using NMR, GPC and DLS. Thiol-induced degradation of the backbone and the assembly of the MRI contrast agent were investigated using GPC and DLS, respectively, and easy degradation was observed. Poly(BAC-AMPD)-g-PEG-g-Gd-DTPA also shows a low cytotoxicity and a high r1 value, so it is promising to provide better MRI imaging with fewer side effects. [ABSTRACT FROM AUTHOR]

A mesoporous poly-melamine-formaldehyde polymer with a high surface area, good porosity and a high density of amine and triazine functional groups was investigated as a highly efficient hydrogen-bonding catalyst. This porous organic polymer was found to be highly effective in catalyzing chemoselective acetalization of aldehydes, without the consumption of any dehydrating agents. The turnover frequency of mesoporous poly-melamine-formaldehyde is hundreds of times higher than melamine monomer, and this high efficiency is due to the high density of aminal (–NH–CH2–NH–) groups and triazine rings in the polymer network, which provides an inherently powerful system with multiple hydrogen bonds. This unique characteristic imparts mesoporous poly-melamine-formaldehyde polymer with a very high activity as a heterogeneous organocatalyst. The polymer is also low cost, and easy to be synthesized and recycled. [ABSTRACT FROM AUTHOR]

An efficient metal-free system using saturated aqueous sodium chloride/aqueous ammonium chloride solution as chlorine source and potassium persulfate as a cheap oxidant for the chlorination of various aromatic compounds including deactivated ones has been developed that proceeds without any acid additive in an excellent regioselective manner. The easy-to-handle aqueous solution/acetonitrile biphasic system as solvent and no need for precautionary measures make this process very practical. [ABSTRACT FROM AUTHOR]

The cover picture shows algae containing caulerpin in the shallow sea under sunshine. Caulerpin is a bis‐indole alkaloid, isolated mostly from algae of genus Caulerpa, it displayed several biological activities meanwhile lack of toxicity for it was found in mouse study. Additionally, caulerpin was also found to be a chemical agent as a rust inhibitor in mild steel. However, the current synthesis methods for caulerpin are not practical for relatively larger scale regarding both low overall yields and critical conditions used, which obviously restricted further exploration of its new applications. This work reported an economical synthesis of caulerpin and subsequently explored its new anticancer activity in several cell lines. More information can be found in the Communication by Hangbin Li et al. (DOI: 10.1002/slct.201802876). Artists: Prof. Liuqun Gu, Hangbin Li, Wenbiao Zhang and Weicong Huang. [ABSTRACT FROM AUTHOR]