水-丁醇两相介质合成SAPO-11和MgAPO-11分子筛

在水-丁醇两相介质中合成了SAPO-11和MgAPO-11分子筛.水-丁醇两相介质有利于在SAPO-11中引入更多的Si,从而产生较多的酸性位,以所得SAPO-11为载体的Pt催化剂在正十二烷临氢异构化反应中表现出较高的催化活性.相反,水-丁醇两相介质不利于Mg进入分子筛骨架,导致MgAPO-11上的酸性位减少,Pt/MgAPO-11催化剂的催化活性降低.     

Transformation ofn-hexane over microporous molecular sieves: Studies over MeAPO-11 and MeAPSO-11

CoAPO-11, MgAPO-11, ZnAPO-11, COAPSO-11, ZnAPSO-11 and MgAPSO-11 samples were synthesized by hydrothermal methods and characterized. The samples were loaded with 0.5 wt.% Pt and tested for their catalytic activities in the isomerization ofn-hexane. All the samples exhibited catalytic activities and selectivities for isomerization comparable to that of SAPO-11. The selectivities for the different monomethyl and dimethyl isomers are rationalized on the basis of shape selectivity and acidities of different samples.     

H-ZSM-11 and Zn-ZSM-11 zeolites and their applications in the catalytic transformation of LDPE

Low density polyethylene was converted into hydrocarbons over Zn- and H-ZSM-11 zeolite catalysts in a fixed-bed reactor during 20 and 60 min reaction time, 0.5 and 2.0 polymer to catalyst mass ratio at 500 °C. The zeolites were synthesized by conventional techniques and characterized by XRD, pyridine FTIR and N₂ adsorption. The adsorbed pyridine spectra demonstrated that new Lewis sites were formed after Zn exchange, and that the relationship between Lewis and Brönsted sites in the Zn-ZSM-11 zeolite (3.53) was much higher than that in the H-ZSM-11 zeolite (0.09). Thermal analyses confirmed that the temperature of decomposition of the polymer can be decreased in as much as about 145 °C when the catalysts were added. As compared to the thermal degradation, the catalytic conversion produced less solid residues and much higher amounts of gas and liquid hydrocarbons. The catalysts showed different yield profiles: the H-ZSM-11 zeolite yielded more gases, while the Zn-ZSM-11 zeolite yielded more liquid products. Notably over Zn-ZSM-11 zeolite, these liquid products were mainly aromatic, and depending on experimental conditions (higher temperature, longer reaction time, smaller polymer/catalyst relationship), aromatic selectivity could be increased to almost 100%.     

1-H2N-CB11F11]---synthesis and reactions of a functionalized fluorinated carbadodecaborate anion

In anhydrous hydrogen fluoride, K[1-H2N-CB11H11] is fluorinated with elemental fluorine to produce K[1-H2N-CB11F11]. Under strong alkaline conditions, two fluorine atoms of the [1-H2N-CB11F11]- anion are regioselectively exchanged, yielding the [1-H2N-4,6-(HO)2-CB11F9]- anion via [1-H2N-6-HO-CB11F10]- as an intermediate. Both hydroxycarborate anions were isolated as [Ph4P]+ salts. All of the species were characterized by IR, Raman, and multi-NMR spectroscopy, thermal analysis (DSC) as well as by mass spectrometry (MALDI). The assignment of the NMR signals was supported by DFT calculations. Solid-state structures of K[1-H2N-CB11F11], [BzPh3P][1-H2N-CB11F11], [Ph4P][1-H2N-4,6-(HO)2-CB11F9], [Ph4P][1-H2N-6-HO-CB11F10], and [BzPh3P][1-H2N-CB11H11] were determined by single-crystal X-ray diffraction.     

Efficient preparation of 9-Z-11-methylretinal and 11-Z-11-methylretinal

[2-(β-Ionylidene)propyl]triphenylphosphonium bromide is reacted with 3-methyl-4-oxobut-2-enenitrile in refluxing 1,2-epoxybutane to give a mixture of 11-Z- and all-E-11-methylretinal via DIBAL-H reduction. In an analogous fashion, β-ionyl triphenylphosphonium bromide is reacted with 3,5-dimethyl-6-oxohexa-2,4-dienenitrile in 1,2-epoxybutane followed by subsequent DIBAL-H reduction to afford a mixture of new products consisting of 9-Z-11-methylretinal, its all-E isomer and 1-(2′,6′,6′-trimethylcyclohex-2′-en-1′-yl)-6-(buten-2″-al-3″-yl)-3,5-dimethylcyclohexa-1,3-diene. These molecules were obtained in pure form by HPLC.     

Expression and Characterization of Hyperthermotolerant Xylanases,SyXyn11P and SyXyn11E,in Pichia pastoris and Escherichia coli

Both Syxyn11P and Syxyn11E, two codon-optimized genes encoding glycoside hydrolase (GH) family 11 hyperthermotolerant xylanases (designated SyXyn11P and SyXyn11E), were synthesized and inserted into pPIC9K^M and pET-28a(+) vectors, respectively. The resulting recombinant expression vectors, pPIC9K^M-Syxyn11P and pET-28a(+)-Syxyn11E, were transformed into Pichia pastoris GS115 and Escherichia coli BL21, respectively. The maximum activities of two recombinant xylanases (reSyXyn11P and reSyXyn11E) expressed in P. pastoris and E. coli reached 30.9 and 17.8 U/ml, respectively. The purified reSyXyn11P and reSyXyn11E displayed the same pH optimum at 6.5 and pH stability at a broad range of 4.5–9.0. The temperature optimum and stability of reSyXyn11P were 85 and 80 °C, higher than those of reSyXyn11E, respectively. Their activities were not significantly affected by metal ions tested and EDTA, but strongly inhibited by Mn²⁺ and Ag⁺. The K _m and V _max of reSyXyn11P toward birchwood xylan were 4.3 mg/ml and 694.6 U/mg, whose K _m was close to that (4.8 mg/ml), but whose V _max was much higher than that (205.6 U/mg) of reSyXyn11E. High-performance liquid chromatography analysis indicated that xylobiose and xylotriose as the major products were excised from insoluble corncob xylan by reSyXyn11P.     

Synthesis and cytotoxic activity of 11-nitro and 11-amino derivatives of acronycine and 6-demethoxyacronycine

Condensation of 2-chloro-3-nitrobenzoic acid with either 5-amino-7-methoxy-2,2-dimethyl-2H-chromene or 5-amino-2,2-dimethyl-2H-chromene afforded diphenylamines 14 and 15. Trifluoroacetic anhydride mediated cyclization gave the corresponding acridones 16 and 17, which were subsequently N-methylated and reduced to 11-aminoacronycine and 11-amino-6-demethoxyacronycine. These two amino compounds, which gave stable water soluble salts, were 2- to 3-fold more potent than acronycine or 6-demethoxyacronycine in inhibiting L1210 cell proliferation.     

Synthesis and Characterization of AlPO4-11 and MAPO-11 Single Crystals

The preparation of two types of molecular sieves AlPO4-11 and MAPO-11 is reported. The particle size of the latter is hundreds of microns, about 10 times larger than that of the former. The XRD, IR and DTA spectra have demonstrated that magnesium has been introduced into the framework of AlPO4-11. The successful preparation of large single crystal of MAPO-11 will open up a new area for the preparation of large molecular sieves crystals in the future. The large MAPO-11 crystal compound is a promising host for the host-guest assembly of composite materials.     

Stereospecific Synthesis of Intermediates for 11-Aza-11-deoxy and 11-Azaprostaglandin Analogues from L-Arabinose

The syntheses of chiral synthons for 11-aza-11-deoxy and 11-azaprostanoids are described. The key intermediate in both routes was 5-O-benzoyl-3C-carboxymethyl-2,3-γ-lactone)-3-deoxy-α-L-lyxo-furanose which is readily available from L-arabinose.     

SAPO—11构型分子筛的合成及结构研究

以二正丙胺及二异丙胺为模板剂,采用水热法制得了SAPO-11分子筛,对3种不同的合成方法——异丙醇铝法、上清液法和氟离子法的产物及杂晶情况作了讨论,采用红外和二次微分红外光谱、XRD多晶结构分析及真空吸附等方法研究了SAPO-11的骨架结构和孔结构。     

Alkylation of quindoline and quindoline-11-carboxylic acid

The reaction between quindoline-11-carboxylic acid and alcohols in acid media gives the quindoline-11-carboxylate esters, but quindoline-11-carboxylic acid or its hydrochloride react with haloalkanes in the presence of basic catalysts and water binders to give 10-alkylquindoline-11-carboxylate esters. 10-Alkylquindolines were obtained similarly. Alkylation of 1-alkylquindoline-11-carboxylate esters in neutral media affords the quaternary salts.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1375–1379, October, 1986.     

Synthesis of 11C-amides using [11C]carbon monoxide and in situ activated amines by palladium-mediated carboxaminations

[11C]Carbon monoxide at low concentrations, aryl halides and amines were used in the palladium-mediated synthesis of twenty 11C-amides. In the study several approaches to improve the radiochemical yield were explored. Eight of the selected amides were prepared by in situ activation of the amines using lithium bis(trimethylsilyl)amide and the radiochemical yields of these reactions were improved compared to utilising a previous reported method. In the synthesis of 1-[carbonyl-11C]benzoyl-3-methyl-1H-indole (11) from 3-methyl-1H-indole (25), the corresponding organotin-amine was prepared prior to the acylation reaction. In a typical experiment, N-(4-hydroxyphenyl)[carbonyl-11C]acetamide (5) was prepared in 15% radiochemical yield using 4-aminophenol (20) but the yield increased to 63% when the amine was activated by lithium bis(trimethylsilyl)amide.     

SAPO—11分子筛的酸性及催化性能

用IR及TPD法研究了SAPO-11分子筛的表面酸性质,并以正庚烷裂解和乙醇脱水为探针研究其催化性能。结果表明,SAPO-11分子筛上既有L酸中心,又有B酸中心,表面上存在4个羟基峰。NH_3-TPD测定了SAPO-11的酸强度和酸中心数,并用矩形法求得脱附活化能,SAPO-11系属中等酸强度的分子筛。     

New route to 1-thia-closo-dodecaborane(11), closo-1-SB11H11, and its halogenation reactions. The effect of the halogen on the dipole moments and the NMR spectra and the importance of spin-orbit coupling for the 11B chemical shifts

Reaction between nido-B10H14 (1) and elemental sulfur in CHCl3 in the presence of Et3N at room temperature, followed by treatment with Et3N.BH3 at 170-190 degrees C, resulted in the isolation of closo-1-SB11H11 (2) in 50% yield. Selected electrophilic halogenation reactions of compound led to the isolation of a series of monohalogenated derivatives of general constitution 12-X-closo-1-SB11H10 (12-X-, where X = Cl, Br, and I). The structures of 12-Cl- and 12-I- were determined by an X-ray diffraction analysis and the structures of all compounds were geometry optimised at the RMP2(fc)/6-31G* level. The constitution of all compounds is consistent with the results of mass spectrometry and multinuclear (1H and 11B) spectroscopy complemented by two-dimensional [11B-11B]-COSY and 1H{11B(selective)} NMR measurements. Experimental 11B chemical shifts generally show acceptable agreement with theoretical values calculated by GIAO methods, but spin-orbit coupling must be included for nuclei bearing heavy-atom substituents such as Br or I. The dipole moments determined for the B12-X bonds show similarities to those of aliphatic C-X bonds and confirm unambiguously the B12 --> S dipole moment orientation in the SB11 cage.     

Asymmetric synthesis of L-2-amino[3-11C]butyric acid, L-[3-11C]norvaline and L-[3-11C]valine

The short-lived radionuclide 11C (t1/2 = 20.4 min) has been used in the asymmetric synthesis of L-2-amino[3-11C]butyric acid, L-[3-11C]-norvaline and L-[3-11C]valine. The syntheses were performed by alkylation of [(+)-2-hydroxypinanyl-3-idene]-glycine tert-butyl ester under anhydrous conditions in tetrahydrofuran/1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone with lithiated 2,2,6,6-tetramethylpiperidine as base, using the appropriate 11C-alkyl iodides prepared in a one-pot reactor from [11C]carbon dioxide. Following removal of the protecting groups, the -[3-11C]amino acids were obtained in 80-82% enantiomeric excess and in 9-25% radiochemical yields, decay corrected and calculated on the basis of the amount of [11C]carbon dioxide at the start of the syntheses within 50-55 min.     

Stereoselective syntheses of 11-α-methoxycurvularin and 11-β-methoxycurvularin

A stereoselective synthesis of potent cytotoxic macrolides, 11-α-methoxycurvularin and 11-β-methoxycurvularin has been accomplished. The synthesis entailed Maruoka asymmetric allylation to introduce the stereocentres at C-11 and the key fragment was installed by using Grubbs cross-metathesis followed by CBS-reduction.     

Automated preparation of carbon-11 ethanol and carbon-11 butanol for human studies using positron emission tomography

An automated continuous flow process has been developed for the synthesis of¹¹C-ethanol and¹¹C-butanol. These alcohols were synthesized via the same route. The reaction of¹¹CO₂ with methylmagnesium bromide or with n-propylmagnesium chloride, followed by a lithium aluminum hydride reduction and hydrolysis produced respectively¹¹C-ethanol and¹¹C-butanol. Preparation can be completed in 25 min. In each case the radiochemical purity, as determined by high pressure liquid chromatography /HPLC/ was greater than 98%. Biological quality control shows that the products are suitable for human use. The process has been completely automated to limit radiation exposure to personnel, reduce preparation time, and increase reproducibility.     

SAPO-11分子筛的合成

以二正丙胺(DPA)为模板剂、利用水热法合成SAPO-11分子筛，系统考察了硅源、硅含量、模板剂用量以及晶化条件（晶化温度、时间以及pH值）对SAPO-11分子筛合成的作用。研究结果表明：硅源是决定SAPO-11分子筛合成及结构的关键组分之一，其释放出活性硅物种的速率要与磷酸铝分子筛的前驱体生成的速度相一致；酸性硅溶胶是合成SAPO-11的合适硅源；在SiO2/Al2O3=0～0.7，DPA/P2O5=0.8～1.8，pH=5.8～7.8条件下，可合成纯SAPO-11分子筛。此外，SAPO-11分子筛的合成，还存在明显的诱导期以及晶型的转化过程。在合成条件下，晶化时间4?h时，SAPO-11开始晶化，至24 h，SAPO-11分子筛可晶化完全。继续延长晶化时间，SAPO-11分子筛与SAPO-31分子筛之间发生转晶现象。     

Synthesis of 11H-Pyrido[2,1-b]quinazolin-11-one and Derivatives

The synthesis of 11H-pyrido[2,1-b]quinazolin-11-one (IV) and derivatives, by the condensation of o-chlorobenzoic acid and 2-aminopyridine in DMF is reported.     

微过氧化物酶-11在壳聚糖修饰玻碳电极上的电化学

采用物理吸附法, 将微过氧化物酶-11(MP-11)固定在载体壳聚糖修饰的玻碳电极表面. 运用循环伏安法对MP-11在该修饰电极上的直接电化学行为及对氧(O2)和过氧化氢(H2O2)的电催化行为进行了表征. 研究结果表明, 在pH=7.12的磷酸盐缓冲溶液中, 壳聚糖修饰电极上的MP-11发生了准可逆的氧化还原反应, 而且在反应过程中包含质子的传递过程, 完全实现了MP-11在该修饰电极上的直接电化学. 该修饰电极也可以对O2和H2O2进行电催化还原, 并且两个反应的电催化还原过程都是受表面控制的电化学过程, 对H2O2催化还原产生的响应电流与H2O2的浓度呈线性关系.