Stereoselective Synthesis of Piperamide Alkaloids by Modified Ramberg-Baecklund Reaction

A convenient and rapid approach for the synthesis ofpiperamide alkaloids la ～ h by the recently developed one-flask Ramberg-Baecklund reaction was described. The synthesis of le was reported for the first time.     

Efficient Synthesis of Octalone

A highly efficient and convergent approach for the synthesis of octalone 1, the focal intermediate for the synthesis of several sesquiterpenoids, was developed based on the cationic cyclization strategy of the functionalized oxabicyclic template 5.     

盐酸戊乙奎醚及其R构型哌啶衍生物的对映专一性合成

A novel and simple procedure for the enantiospecific synthesis of penehyclidine hydrochloride （8018） isomers and the R configuration derivatives was described. The intramolecular asymmetric cyclization of the monosulfonate of compound 1,2-diol was applied to the execution of the synthesis of the key chiral building block for the first time. The aimed products were obtained with moderate yield in〉99% ee.     

A convenient synthesis of ezetimibe analogs as cholesterol absorption inhibitors

<正>A convenient method for the synthesis of ezetimibe analogs as cholesterol absorption inhibitors was described.The key step in the synthesis was the intramolecular ring formation through Mitsunobu reaction.Furthermore,a new series of analogs was designed and synthesized.     

Effect of Ca promoter on LPG synthesis from syngas over hybrid catalyst

Direct synthesis of liquefied petroleum gas (LPG) from syngas was carried out over hybrid catalyst consisting of methanol synthesis catalyst and Y zeolite modified with Pd and Ca by different methods. The decrease of CO conversion was mostly attributable to the sintering of Cu in methanol synthesis catalyst. On the other hand, coke deposition on the Y zeolite was the main reason for the decrease of LPG selectivity. The introduction of Ca decreased the strong acid sites of Y zeolite, suppressed coke formation, and thus improved the stability of hybrid catalyst.     

Synthesis and Photochemistry of Diphenylchlorin and Diphenylbacteriochlorin

5, 15-Diphenylporphyrin (DPP), a novel porphyrin model compound, was always inaccessible in quantities suitable for study1 because the difficulty of synthesis. So that the characteristic of this molecule had not been explored until a novel method developed for the preparation of DPP recently2. Therefore it will be possible for the synthesis of DPP-based photosensitizers, and investigation of their photodynamic properties. Here we reported the synthesis of novel photosensitizers 5, 15-diphe…     

Synthesis of A-B-C-ring Tricyclic Core of iso-Merrilactone A

A desymmetrization approach for the synthesis of the A-B-C tricycle intermediate of iso-merrilactone A was described. The key steps of this synthesis to efficiently access the tetracyclic Illicium sesquiterpenes core included an intramolecular aldol cyclization and an oxidative lactonization reaction. A novel Au catalyzed hydrolytic cyclorearrangement cascade reaction was explored in the initial stage.     

New Rh—ZnO／Carbon Nanotubes Catalyst for Methanol Synthesis

A new catalyst for methanol synthesis,ZnO-promoted rhodium supported on carbon nanotubes,was developed.It was found that the Rh-ZnO/CNTs catalyst had high activity of 411.4mg CH3OH/g/cat/h and selectivity of 96.7% for methanol at 1 MPa and 523 K.The activity of this catalyst is much higher than that of NC 207 catalyst at the same reaction conditions.It was suggested that the multi-walled strueture CNTs favored both the couple transfer of the proton and clectron over the surface of the catalyst and the uptake of hydrogen which was favorable to methanol synthesis.     

STUDIES ON THE SYNTHESIS OF DIMETHYI,4-HYDROXY -4''''-METHOXY-5,6,5'''',6''''-BISMETHYLENEDIOXYBIPHENYL-2,2''''-DICAPBOXYLATE——AN ESSENTIAL METABOLITE OF DDB

This paper reports the total synthesis of dimethyl4-hydroxy-4’-methoxy-5,6,5’,6’-bismethylenedioxybiphenyl-2,2’-dicarboxylate(Ⅱ).Various conditions for bromination were tried to find the best one for synthesis of thekey intermediate compd 6.After Lllmann condensation of 6 with 8 and hydrogenolysis,the title compd Ⅱ was obtained.It was proved to be identical with the isolatedmetabolite of DDB by spectral data.     

Ethylene glycol aluminum as a novel catalyst for the synthesis of poly(ethylene terephthalate)

Ethylene glycol aluminum was prepared efficiently and characterized by FT-IR and NMR.It exhibited higher catalytic activity and had profitable effect than titanium glycolate and ethylene glycol antimony for the synthesis of poly(ethylene terephthalate) (PET).It was only used as polycondensation catalyst because it was sensitive to water.For this catalyst,the degree of esterification of the theoretical amount of water was produced up to 95%at 260℃,while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PET polyester,polymerized at 280℃,70 Pa for 39 min,was 0.87 dL/g and 23.0μmol/g,respectively. Ethylene glycol aluminum was a promising catalyst for the synthesis of PET polyester.     

Stannous oxalate as a novel catalyst for the synthesis of polytrimethylene terephthalate

Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibited higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate (PTT) via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260°C after 1.5 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polyester, polymerized at 260°C, 60 Pa for 2 h, was 0.8950 dL/g and 15 mol/t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester.     

An Efficient Synthesis of Aromatic 1-Hydroxymethylene-1,1-bisphosphonates from Aldehydes

A simple and efficient procedure for synthesis of 1-hydroxymethylene-1,1-bisphosphoates from aldchydes is described.This method was applied to the synthesis of novel catechol substituted bisphosphonates as the anti-osteoporosis agents.     

Characterization and catalytic performance of CeO2-Co/SiO2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species （-CH2-）. Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity （GHSV）, and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.     

A Simple Synthesis of dl—Shikonin

A new facile route for the synthesis of dl-shikomin is presented.Reformatsky reaction assisted cross-coupling of 1,4,5,8-tertramethoxynaphthalene-2-carbaldehyde and ethyl-bromoacetate was empolyed for introduction of the side chain of dl-shikonin.     

Stannous-acetylacetonate： A new catalyst for poly（trimethylene terephthalate） synthesis

Stannous-acetylacetonate was prepared efficiently and characterized by 1H NMR and FT-IR. Its catalytic activity for poly(trimethylene terephthalate) (PTT) synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260°C for 2 h, while the intrinsic viscosity and content of ter- minal carboxyl groups of the corresponding PTT polymerized at 260°C, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t, respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.     

碘催化的亚胺Diels-Alder反应：有效地合成四氢喹啉衍生物

Iodine was found to be an efficient catalyst for the imino Diels-Alder reaction of N-arylimine with enol ethers toprovide tetrahydroquinolines in good yields.The influence of the loading of iodine,reaction solvent,the structure ofimine and enol ethers was studied.One pot synthesis of tetrahydroquinolines from aldehyde,aniline and enol etherscatalyzed by iodine was also applicable and provided tetrahydroquinolines in comparable yields.Mild reaction con-ditions,facile experimental procedure,low price of iodine and good yield of products render this new method at-tractive for practical synthesis of many tetrahydroquinoline derivatives.     

Synthesis of a novel tri-antennary galactoside with high hepatocyte targeting

A novel bifunctional compound carrying cluster thiogalactoside as the cell targeting ligands was synthesized for gene delivery to hepatocytes. Tetra-antennary dendr-OMs4 5 was used as a scaffold for the attachment of three galactosides, while the other mesylate end was linked with cholesterol through poly(ethylene glycol) chain. This design provided an effective entry for the synthesis of the bifunctional compound.     

Highly selective synthesis of 3-methylindole from glycerol and aniline over Cu/NaY modified by K2O

The vapor-phase synthesis of 3-methylindole from glycerol and aniline over Cu/NaY modified by K2O was investigated. The catalysts were characterized by X-ray diffraction （XRD） and the temperature- programmed desorption of ammonia （NH3-TPD）. The effect of the reaction temperature on the activity and selectivity of Cu]NaY-K2O catalyst was also investigated. The results indicated that the addition of K2O to Cu/NaY increased the selectivity of the catalyst remarkably because the amount of middle-strong acid sites decreased clearly. The decrease of the reaction temperature was beneficial for the increase of 3- methylindole selectivity. Over Cu/NaY-K2O, the selectivity of 3-methylindole reached 75% and the yield of the target product was up to 47% at 220 ℃. A probable catalytic mechanism for the synthesis of 3- methylindole from glycerol and aniline was proposed.     

稻壳灰负载FeCl2·2H2O:一个温和高效的多相催化剂用于Friedlnder杂成环反应合成多取代喹啉（英文）

Rice husk ash was used as a new, green, and cheap adsorbent for FeCl3. Characterization of the obtained reagent showed that rice husk ash supported FeCl2·2H2O was formed. This reagent is efficient at catalyzing the synthesis of multisubstituted quinolines by the Friedl鋘der heteroannulation of o‐aminoaryl ketones with ketones or β‐diketones under mild reaction conditions. This methodology allows for the synthesis of a broad range of substituted quinolines in high yields and with excellent regioselectivity in the absence of a solvent.     

Highly efficient heterogeneous procedure for the synthesis of fructone fragrancy

A novel heterogeneous strong acid catalyst was synthesized through the copolymerization of p-toluenesulfonic acid and paraformaldehyde and utilized for the synthesis of fructone. The results showed that the catalyst was very efficient for the reaction with the yield over 95%. The advantages of extremely high density of acidity, high thermal and chemical stability, low cost for the simple synthetic procedure, and reusability made the catalyst one of the best choices for the reaction.