Solvent Effect of DMSO-d_6 on 1,2-Diols in ~1H NMR

There is a classic experiential rule about 1,2-diol RCR^1 （OH） CR^1 （OH） R（ R^1 = H or methyl）, that is, the proton chemical shift of the α-R^1 group at the hydroxvl group in the all-isomer, in general, aPPears in a higher field with ca.

Enantioselective Synthesis of Terminal 1,2-Diols from Acyl Chlorides

Optically active terminal 1,2-diols were prepared with high enantiopurity via the TMS-quinidine-catalyzed en- antioselective cyclization of acyl chlorides and oxaziridine, followed by reductive ring-opening of the cycloadducts.

Lacunary silicotungstic heteropoly salts as high-performance catalysts in oxidation of cyclopentene

The development of polyoxometalates for olefin oxidation is critical to achieving the green chemical process of the C5 fraction further processing.Di-lacunary silicotungstic anions were easily obtained by continuously adjusting the p H instead of the traditional step-by-step method,which exhibited excellent performance in the catalytic oxidation of cyclopentene(CPE)to aldehydes or alcohols.The 93.69%CPE conversion and 97.15%total product selectivity(41.38%for glutaraldehyde(GA)and 55.77%for 1,2-cyclopentanediol(1,2-diol)were achieved by using H_(2)O_(2)as the oxidant and acetonitrile as the solvent.Through complementary characterization,it was found that the optimized di-lacunary silicotungstic polyoxometalate retained a complete Keggin structure,and exhibited better catalytic activity and stability than the mono-lacunary or saturated silicodecatungstate because it exposed more catalytic active centers.Furthermore,in situ FT-IR spectra was utilized to monitor the reaction process,revealing the formation of the active species W(O_(2))on the di-lacunary silicotungstic polyoxometalate and the intermediate epoxycyclopentane during the catalytic oxidation of cyclopentene.

Recent advances on controllable and selective catalytic oxidation of cyclohexene

Because of multiple potential reaction sites and variable oxidation depths,oxidation of cyclohexene can lead to a mixture of products with different oxidation states and functional groups,such as 7-oxabicyclo[4.1.0]heptane,trans/cis-cyclohexane-1,2-diol,cyclohex-2-en-1-ol,cyclohex-2-en-1-one,and even adipic acid.These products are broadly and abundantly used intermediates in the chemical industry;therefore,controllable oxidation reactions for cyclohexene that can selectively afford the targeted products are synthetically valuable for applications in both the academy and industry,thus becoming the aim of synthetic and catalytic chemists in the field.Many reports on selective oxidation of cyclohexene have recently appeared in the literature because of its significance.This short review summarizes the recent advances on this subject,and the contents are mainly classified based on the chosen oxidants.We hope that this review can provide a useful guide for controllable and selective catalytic oxidation of cyclohexene for interested readers from both the academy and industry.

Two new phenolic compounds from Ardisia gigantifolia

Two new compounds were isolated from the 60% ethanol extract of the dried rhizome of Ardisia gigantifolia Stapf. The structures were elucidated on the basis of spectroscopic methods as （＋）-5-（1,2-dihydroxypentyl）-benzene- 1,3-diol and （-）-5-（1,2- dihydroxypentyl）benzene- 1,3-diol.

Hydrogen bonding-induced oxygen clusters and long-lived room temperature phosphorescence from amorphous polyols

Developing non-conjugated luminescent polymers(NCLPs)with fluorescence and long-lived roomtemperature phosphorescence is of great significance for revealing the essence of NCLPs luminescence,which has gradually attracted the attention of researchers in recent years.Herein,polymethylol(PMO)and poly(3-butene-1,2-diol)(PBD)with polyhydroxy structures were prepared and their luminescence behaviors were investigated to reveal the clusteroluminescence(CL)mechanism.Compared with polyvinyl alcohol with non-luminescent behavior,PMO and PBD exhibit cyan-blue fluorescence with quantum yields of ca.12%and green room-temperature phosphorescence with lifetimes of ca.89 ms in the solid state.Both fluorescence and phosphorescence exhibit typical excitation-dependent CL behavior.Experimental and theoretical analyses show that the strong hydrogen-bonding interaction of PMO and PBD greatly promotes the formation of oxygen clusters and the through-space n-n interaction of oxygen atoms,enabling fluorescence and phosphorescence emission.Our results have enormous implications for understanding the CL mechanism of NCLPs and provide a new polymer design strategy for the rational design of novel NCLPs materials.

Changes in PAH and 3-MCPDE contents at the various stages of Camellia oleifera seed oil refining

Objectives:Polycyclic aromatic hydrocarbons(PAHs)and 3-monochloropropane-1,2-diol ester(3-MCPDE)were studied in camellia oil.It is important to study the changes in the content of PAHs and 3-MCPDE at different refining stages(from crude oil to the final refined oil product)to elucidate the influence of the refining procedures on their change.Materials and methods:The PAHs and 3-MCPDE in camellia oil from different refining stages(from crude oil to the product)of a plant were analyzed by gas chromatography–mass spectrometry and calculated by the internal standard method.Results:The overall PAH content was(79.64±2.43)μg/kg in crude camellia oil.After refining treatment,the PAH content decreased to(18.75±0.55)μg/kg.The 3-MCPDE content increased during the refining process from 0 mg/kg in the crude oil to 4.62 mg/kg in the refined oil product.Conclusions:This is the first study to simultaneously monitor changes in both PAH and 3-MCPDE contents during the production of camellia oil.These results confirmed the effectiveness of the refining method on PAH removal and the increase in 3-MCPDE at high temperature.It is suggested that novel processing methods or refining parameters need further optimization to decrease the overall concentrations of PAHs and 3-MCPDE in camellia oil.