A Facile Approach to Synthesis of the Di-O-methyl Ethers of （-）-Agatharesinol, （-）-Sugiresinol, （＋）-Nyasol and （＋）-Tetrahydronyasol

The facile enantioselective synthesis of the di-O-methyl ethers of （-）-agatharesinol （1b）, （-）-sugiresionl （2b）, （＋）-nyasol （3b） and （＋）-tetrahydronyasol （4） were achieved in high yield. The absolute configuration of （＋）-3a was confirmed via first total synthesis of （＋）-3b and （＋）-4.     

Asymmetric Synthesis of the C（17）——C（28） Subunit of Didemnaketal B

The stereocontrolled synthesis of the C（17）--C（28） fragment 3 of didemnaketal B was accomplished in 21 steps from the natural （R）-（＋）-pulegone and （S）-（--）-citronellal. The key steps involved diastereoselective construction of two chiral carbon centers through the intramolecular chiral induction and uncommon Julia olefination of ketone forming the E-trisubstituted C（22）--C（23） double bound.     

A practical synthesis of （-）fosfomycin from its enantiomer

（＋）-cis-（1S, 2R）-Epoxypropylphosphonic acid, the enantiomer of fosfomycin, which is the industrial side-product in the preparation of the antibiotic fosfomycin, was converted into （-）fosfomycin by a seven-step procedure. The esterification of the dihydroxyphosphonic intermediate was the key step. The title compound was obtained in good yield and its optical purity was up to the medicine quality standard of Chinese Pharmacopoeia.     

Asymmetric Synthesis of （R）- and （S）-Moprolol

A simple and effective procedure for the enantioselective synthesis of （R）- and （S）-moprolol was described. The key step was the asymmetric synthesis of enantiopure （R）- and （S）-guaifenesin, which were synthesized from enantioenriched （R）-3-chloro-l,2-propanediol and （S）-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co^Ⅲ complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by ^1H NMR, ^13C NMR, IR, and MS.     

An enantioselective formal synthesis of （-）-thujopsene

Dihydromayurone （3）, a key intermediate to synthesize （-）-thujopsene （1）, was efficient enantiocontrolled synthesized from （＋）-dihydrocarvone through 9 steps in an overall yield of 19.3%. The key step was the Simmons-Smith reaction.     

One-pot synthesis of 2-（1-acyloxypentyl） benzoic acids

A one-pot synthesis of 2-（1-acyloxypcntyl） benzoic acids by trapping the carboxylatc/alkoxide dianion with acylating reagents following Grignard addition with n-BuMgBr to 2-formylbcnzoic acid was described. Compared with routine synthetic method, this novel procedure has the advantage of convenient operation and higher yields.     

Synthesis and Absorption Properties of New Na Specific Adsorbent Li（1＋x）AlxTi（2-x）（PO4）3

A new kind of adsorbent Li（1＋x）AlxTi（2-x）（PO4）3 was synthesized by solid state reaction method. The influence of the content of doping aluminum on the adsorbent Li（1＋x）AlxTi（2-x）（PO4）3 was investigated by XRD, while the morphology of powders was observed by SEM. The investigation of the adsorption properties showed that the adsorbent can selectively adsorb sodium with the adsorption capacity of 11.76 mg/g. The optimum conditions of adsorption are at pH 10.0-11.0 in LiCl solution.     

A concise formal stereoselective total synthesis of （-）-swainsonine

A short formal stereoselective synthesis of （-）-swainsonine （1） is described. Our synthesis started with the versatile building block （R）-3-benzyloxyglutarimide 5. Through controlled regioselective reduction, Ley＇s-sulfone chemistry （N-α-sulfonylation and ZnCl2-catalyzed N-α-amidovinylation）, an RCM reaction, and an amide reduction, the synthesis of unsaturated indolizidine （8R,8aS）-3 has been achieved in five steps. The indolizidine （8R,8aS）-3 is an advanced intermediate toward the synthesis of （-）-swainsonine （1）.     

Scattering Resonance State of Br＋HBr（v=0）→BrH（v＇=0）＋Br Reaction Explored by Partial Potential Energy Surface Method

The partial potential energy surface（PPES） of Br＋HBr（v=0）→BrH（v＇=0）＋Br was designed by coupling the vibration energy and the minimum energy of the corresponding reaction path, Vmep. All the calculations were performed at the theoritical level of QCISD（T）/6-311＋＋G＊＊//MP2/6-31 1＋＋G＊＊. Based on the analysis of PPES, the dynamic ＂Eyring Lake＂ mechanism gave birth to the scattering resonance state. The resonance energy was also obtained via PPES. Then a lifetime matrix of the resonance state was established by solving the translational wave-function via the numerical propagation method. Then the reaction resonance lifetime was calculated to be 125 fs. It is in good agreement with the experimental result.     

First total synthesis of （±）-malaysianone A and （±）-tanariflavanones B

A concise approach for the frst total synthesis of two naturally occurring flavanoids,（）-malaysianone A（1）and（）-tanariflavanones B（2）,has been accomplished with total yields of 12.9%and 10.4%,respectively.The key steps were regioselective deprotection and regioselective synthesis of 5-formaldehyde-8-hydroxy-2-[40-methyl-30-penteneyl]-dihydro-1-benzopyran（8）.     

Enantioselective Total Synthesis of the （＋） Antipode of Zeylenone

Starting from shikimic acid, the total synthesis of zeylenone was studied. The product was proved to be the ( )antipode of zeylenone through analysis and comparison of their respective spectra (including NMR, MS, IR and CD) and optical data. The absolute configuration of the natural product was thus determined to be (1 S,2S,3R).     

Theoretical Investigation on the Adsorption of Ag^＋ and Hydrated Ag^＋ Cations on Clean Si（111） Surface

In this paper, the adsorption of Ag^＋ and hydrated Ag^＋ cations on clean Si（111） surface were investigated by using cluster （Gaussian 03） and periodic （DMol^3） ab initio calculations. Si（111） surface was described with cluster models （Si14H17 and Si22H21） and a four-silicon layer slab with periodic boundary conditions. The effect of basis set superposition error （BSSE） was taken into account by applying the counterpoise correction. The calculated results indicated that the binding energies between hydrated Ag^＋ cations and clean Si（111） surface are large, suggesting a strong interaction between hydrated Ag^＋ cations and the semiconductor surface. With the increase of number, water molecules form hydrogen bond network with one another and only one water molecule binds directly to the Ag^＋ cation. The Ag^＋ cation in aqueous solution will safely attach to the clean Si（111） surface.     

Effect of Mn（Ⅱ） and Ce（Ⅳ） Ions on the Oxidation of Lactic Acid by Chromic Acid

The kinetics and mechanism of lactic acid oxidation in the presence of Mn（Ⅱ） and Ce（Ⅳ） ions by chromic acid were studied spectrophotometrically. The oxidation of lactic acid by Cr（Ⅵ） was found to proceed in two measurable steps, both of which gave pyruvic acid as the primary product in the absence of Mn（Ⅱ）.2Cr（Ⅵ）＋2CH3CHOHCOOH→2CH3COCOOH＋Cr（Ⅴ）＋C（Ⅲ） Cr（V）＋CH3CHOHCOOH→Cr（Ⅲ）＋CH3COCOOHThe observed kinetics was explained due to the catalytic and inhibitory effects of Mn（Ⅱ） and Ce（Ⅳ） on the lactic acid oxidation by Cr（Ⅵ）. The reactivity of lactic acid depends upon the experimental conditions. It acts as a two- or three- equivalent reducing agent in the absence or presence of Mn（Ⅱ）. It was examined that Cr（Ⅲ） products resulting from the direct reduction of Cr（Ⅵ） by three-equivalent reducing agents. The oxidation of lactic acid follows the complex order kinetics with respect to [lactic acid]. The activation parameters Eo, △H^#, and AS^# were calculated and discussed.     

Promoting effect of ethanol on the synthesis of N-（2-methylphenyl）-hydroxylamine from o-nitrotoluene in Zn/H2O/CO2 system

The promoting effect of ethanol on the synthesis of N-（2-methylphenyl）hydroxylamine from o-nitrotoluene in Zn/H₂O/CO₂ system was observed.By adding appropriate amount of ethanol,the selectivity of N-（2-methylphenyl）hydroxylamine increased from 71%to 90%when the reduction was carried out at 25℃under normal pressure of CO₂.     

Preparation and Characterization of High Purity Al（2-x）Mg（x＋y）Ti（1-y）O（5-0.5x-y） Solid Solution

A small amount of mineralizer MgO was added into Al2TiO5 synthesized from the sludge of aluminum factory to form Al（2-x）Mg（x＋y）Ti（1-y）O（5-0.5x-y） solid solution and inhibit the decomposition of Al2TiO5 solid solution. It increased the content of Al2TiO5 solid solution and improved the thermal stability of materials. In this work,XRD and SEM methods were adopted to characterize the crystalline structure and microstructure of each kind of sample. Rietveld Quantification method was used to determine the content of crystalline phases in each sample. Results show as follows： the optimal addition concentration of MgO was 2.0%,and the corresponding content of Al2TiO5 solid solution which displayed irregular bulk shape was 100%; the addition of mineralizer MgO could enhance the flexural strength and thermal stability of Al2TiO5 solid solution materials. The optimal addition concentration of MgO determined by performance analysis was 2.0%,and its corresponding retention rate of thermal-shock flexural strength was 86.4%. Structure analysis and performance analysis resulted in good accordance.     

EFFECTS OF L-PHENYLALANINE ON THE RADIATION SYNTHESIS OF POLY （N,N＇-METHYLENEBIS A CR YLAMIDE-co-4-VINYLPYRID INE） （MICRO）GELS

The effects of L-phenylalanine （L-Phe） on the synthesis ofpoly（N,N＇-methylenebisacrylamide-co-4-vinylpyridine） （poly（Bis-co-4-VP）） （micro）gels by γ-ray irradiation were studied. The addition of L-Phe could not only decrease the gelation dose （Dg） of the synthesis obviously, but also transform the morphology of copolymer from microgel to gel. In addition, the swelling ability of the （micro）gels was also affected in the presence of L-Phe. The decrease of Dg was ascribed to the effect of pH, while the transformation of the morphology was ascribed to the effect of L-Phe on the stability of the poly（Bis-co-4-VP） microgel. Such an effect was confirmed further as compared with the effects of L-alanine, L-glutamic acid, L-arginine, sulfuric acid and aqueous ammonia.     

First Synthesis of （＋）-2,14-Deoxyalatol from α-Santonin

A novel and general approach for synthesis of the multi-oxygenated dihydrofuran sesquiterpenes has been developed starting from santonin. The key steps involve: the strategic acid-catalyzed double-bond shifting affording 4, the novel base-promoted epoxide rearrangement of 5 generating two key functionals (the C5-OH and the Δ^7,11 double bond), and the stereoselective cyclization of tetrahydrofuran ring without pre-controlling the stereochemistry of C-7. As an example of this approach, synthesis of ( )-2,14-deoxyalatol was described in detail.     

A Convenient Synthesis of 6,8-Dimethoxy-3-[（2-（4-methoxyphenyl）ethyl）isocoumarin

6,8-Dimethoxy-3-[2-（4-methoxyphenyl）ethyl]isocoumarin was synthesized by condensation of 5,7-dimethoxyhompophthalic acid with 3-（4-methoxyphenyl）propanoyl chloride. The structure of the synthesized compound was confirmed by its mass spectrometric studies. The synthesized compound serves as a model for synthesis of DL-agrimonolide.     

First total synthesis of （±）-abyssinoflavanone V

The total synthesis of （±）-abyssinoflavanone V was first achieved through C-prenylation, selective protection of phenolic hydroxyl group, aldol condensation, cyclization and deprotection starting from cheap 4-hydroxybenzaldehyde and 2,4,6- trihydroxyacetophenone, with total yield 24%. All structures of new compounds were confirmed by IR, 1^H NMR and MS.     

Microwave activated synthesis of 2-aryl-quinazolin-4（3H）ones

A highly efficient synthesis of 2-aryl-quinazolin-4(3H)ones was performed by one-pot oxidative heterocyclization of 2- aminobenzamide with aldehydes in the presence of potassium permanganate in dimethylacetamide under microwave irradiation.