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1.
左联  周建忠  姚天爵 《色谱》1999,17(1):46-48
 利用高效DEAE离子交换液相色谱法分离纯化了绿脓杆菌标准菌株PAO1外膜蛋白。流动相为pH8.0Tris-HCl缓冲液,色谱柱为TSKgel-DEAE-5PW(0.75cm×7.5cmi.d.)。通过纯化外膜蛋白,可以为研究绿脓杆菌外膜通透性与抗生素耐药性之间的关系及缩短研究周期提供有效的方法。  相似文献   

2.
陈兰化 《分析化学》1995,23(11):1333-1336
在PH5.5-7.0的HAc-NaAc缓冲溶液中,锆与氟、7-碘-8-羟基喹啉-5磺酸、EDTA及十六烷基溴化铵形成五元荧光络合物,其组成为Zr(Ⅳ):F:H2QSI:EDTA:CTMAB=1:2:1:1:4。络合物的最大激发波长(λex)为365nm,最大发射波长为500nm。  相似文献   

3.
研究了在TritonX-100存在下,在PH8.0的乙醇介质中,用5-Br-PADAP作为显色剂,应用分光光度法连续测定血清中的铜,锌。本法具有较高的灵敏度,Cu^2+-5-Br-PADAP的ε为8.50*10^4L.mol^-1.cm^-1,Zn^2+-5-Br-PADAP的ε为9.65*10^4L.mol^-1.cm^-1。铜线性范围为0-0.45mg.L^-1,锌线性范围为0-0.40mg.  相似文献   

4.
Base-CatalyzedRearrangementof11-Isopropylidene-anti-4,5-Epoxyendo-Tricyclo[6.2.1.0~(2,7)]Undeca-4,9-Diene-3,6-DioneXiaoPeiGUA?..  相似文献   

5.
STUDIESONTHESYNTHESISOFSESAMIN-GROUPLIGNANSV.ACONVENIENTMETHODFORTHEPREPARATIONOF2-ARYL-4-PHENYLOXAZOLES¥Correspondentauthor.2-aryl-4-phenyloxazoles.Theotherollebythereactionofa-methylphenacylbenzoatewithammoniumacetateinboilingaceticacidtoformafutureof2,4-diphenyl-5methyloxazoleand2,4-diphenyl-5-rnethylinddazolebothinabout40%yield,hilttillsmethodisapplicableforthepreparationof2-aryl-4-phenyloxazoles.Byanalogy,plienacylbenzoateisalloallowedtoreactwithalnmonillmacetateinboilingaceticacid.Amixtureof2,4-diph  相似文献   

6.
2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)在极谱和伏安分析中的应用已有一些报道。陈林林等曾经研究过Ti(Ⅳ)-5-Br-PADAP络合物在稀H2SO4-H2C2O4溶液中的极谱行为,但灵敏度不高(1.0×10-7mol/L)。我们发现,在pH4.1左右的HAc-NaAc底液中,Ti(Ⅳ)-5-Br-PADAP-NaClO3体系产生一灵敏的极谱吸附催化波,二次导数峰电位在-0.86V(vs.SCE)左右,波形良好,波高稳定,检测限可达4×10-10mol/L。1 实验部…  相似文献   

7.
微米级聚酯醚嵌段共聚物微球的制备及其蛋白包裹研究   总被引:19,自引:0,他引:19  
聚酯 醚嵌段共聚物聚 D,L 乳酸 聚乙二醇(Poly DL lactide Polyethyleneglycol,PLA PEG)采用本体聚合法在180℃及-95×10-2MPa条件下制得.光谱分析证实产物结构.采用乳液溶剂蒸发法制备PLA PEG微球,粒径<5μm.以复合乳液技术包裹蛋白.差示扫描量热分析确证PLA PEG有效包裹蛋白.BCA法检测微球蛋白含量.结果表明与均聚物PLA比较,PLA PEG不仅改善了成球条件而且蛋白的包裹效率明显提高.  相似文献   

8.
口服聚酯聚醚疫苗蛋白微球的制备研究   总被引:10,自引:0,他引:10  
采用本体聚合法合成不同聚醚含量的聚酯聚醚嵌段共聚物聚 DL 乳酸 聚乙二醇(Poly DL lactide b polyethyleneglycol,PELA).PELA及PLA包裹人血清白蛋白(HSA)微球采用溶剂挥发法双乳液体系(W1/O/W2)制备.微球球形规整,粒径集中在05~50μm.用CBB法检测微球中蛋白含量,蛋白包裹量达25%,包裹效率近80%.从双乳液体系中界面张力角度考察了聚合物囊材的性质、稳定剂的种类及W1/O的稳定性等对微球粒径及蛋白包裹量的影响.微球体外释放结果表明PELA蛋白微球的突释现象不明显,释放速度较为恒定.  相似文献   

9.
研究了二-(邻-甲苯基)硫卡巴腙(简写为H2DMBDz)与Pb(Ⅱ)和Cd(Ⅱ)配合物体系的二阶导数吸附极谱波。在pH6.0的HAc-NaAc介质中,Pb(Ⅱ)-(H2DMBDz)和Cd(Ⅱ)-(H2DMBDz)2配合物分别于-0.52V(υs.SCE)和-0.65V(υs.SCE)电位处产生一良好的可逆吸附极谱波。峰电流I″p1和I″p2分别与Pb(Ⅱ)的浓度c1和Cd(Ⅱ)的浓度c2在0.01  相似文献   

10.
天青Ⅰ修饰电极的电化学性质及对血红蛋白的电催化还原   总被引:8,自引:0,他引:8  
天青Ⅰ修饰电极在PH=5.5的HAc-NaAc缓冲溶液中,在0.3--0.7V电位范围内表现出可逆的氧化还原行为,其表面式量电位E^0=-0.21V该电极对血红蛋白的还原过程具有良好的催化作用。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

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