快速弱阴离子交换无孔聚合物固定相的制及用于蛋白质的高效液相色谱分离

将粒径为3.0 μm无孔单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂(PGMA/EDMA)的表面经不同的化学方法改性,制备了两种不同配基的弱阴离子交换(WAX-Ⅰ和WAX-Ⅱ)色谱填料.在同等色谱条件下,比较了两种填料对蛋白质的分离性能,发现WAX-Ⅰ型填料分离性能优于WAX-Ⅱ.详细考察了WAX-Ⅰ型弱阴离子交换色谱填料流动相pH值、流速及有机溶剂等对蛋白质保留的影响.实验结果表明,当流动相流速为3mL/min时,4种标准蛋白可在2 min内基线快速分离,蛋白质的保留符合阴离子交换色谱规律.该填料可以用于生物工程产品的快速分离和纯化.     

原子转移自由基聚合法制备强阴离子交换色谱填料及其在蛋白质分离中的应用

在大孔硅胶表面引入原子转移自由基聚合的引发基团,通过该技术将甲基丙烯酰氧乙基三甲基氯化铵聚合于硅胶表面,制得了强阴离子交换色谱填料.详细考察了该填料对标准蛋白质的分离性能及流动相pH、流速、有机溶剂对蛋白质保留的影响.实验结果表明,在流速为0.75 mL/min时,采用线性梯度洗脱,20 min内可快速分离不同体系的三种标准蛋白;并将该填料用于鸡蛋中卵清蛋白的快速分离纯化,取得了很好的效果.     

无孔单分散亲水性中强阳离子交换树脂的制备及其在蛋白质快速分离中的应用研究

以3.0μm无孔单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂为基质,将其表面经新的化学方法改性后制备了一种新型的无孔中强阳离子交换色谱填料。详细考察了该无孔填料对标准蛋白分离性能,有机溶剂、pH、流动相盐种类和流速等对蛋白质保留的影响。实验结果表明,在流速为4 mL/min时,线性梯度时间在2.0 min内可快速分离4种标准蛋白,蛋白质的保留符合阳离子交换色谱规律。将其应用于快速纯化鸡蛋清中的溶菌酶,取得较好效果。     

以单分散树脂为基质的中强阳离子交换色谱填料的合成及应用

将粒径为8.0μm多孔单分散交联氯甲基苯乙烯-二乙烯苯树脂的表面经化学方法改性,得到了一种亲水性良好的中强阳离子交换色谱填料,详细考察了该改性后树脂的表面亲水性、对标准蛋白的分离性能、盐种类及盐浓度对蛋白保留行为的影响。实验结果表明,当流动相流速为3 mL/min时,四种标准蛋白可在3min内基线快速分离,蛋白质的保留符合阳离子交换色谱规律。该填料应用于鸡蛋清中溶菌酶快速分离纯化,取得较好效果。     

无孔单分散亲水性强阳离子交换固定相的制备及其在蛋白质快速分离中的应用研究

采用分散聚合法制备小颗粒种子及“一步种子溶胀聚合”法成功地制备了粒径为3.0 μm的无孔单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂,其表面经水解、环氧化、再水解后与氯磺酸反应,制备了一种新型的强阳离子交换色谱填料（SCX）。详细考察了该填料对标准蛋白质的分离性能及流动相中盐的种类、有机溶剂、流速等对蛋白质保留的影响。实验结果表明,在流速为4 mL/min时,采用线性梯度洗脱,1.0 min内可快速分离4种标准蛋白质,蛋白质的保留符合阳离子交换色谱规律。将SCX应用于快速纯化鸡蛋清中的溶菌酶和猪心中的细胞色素-C,取得了较好的效果。     

单分散大孔亲水弱阳离子交换填料的制备及其对鱼精蛋白的分离纯化

以自制的5.0 μm单分散大孔亲水交联聚甲基丙烯酸环氧丙酯(PGMA/EDMA)微球为基质,对其表面进行化学改性,合成弱阳离子交换色谱填料(WCX)。详细考察了该填料对标准蛋白质的分离性能、表面亲水性能、稳定性和重现性以及流速对蛋白保留的影响。实验结果表明,该色谱填料对蛋白的分离性能、重现性及稳定性良好;在流速为3 mL/min时,采用线性梯度洗脱,6 min内可分离4种标准碱性蛋白质,以溶菌酶测定的该填料的动力学吸附容量为29.86 mg/g。将其用于鱼精蛋白的分离纯化,经反相高效液相色谱测定纯化后鱼精蛋白的纯度为99.2%;与商品Shodex IEC SP-825强阳离子交换色谱柱比较,纯化结果几乎一样。     

无孔单分散离子交换硅胶键合相用于蛋白质的高效液相色谱分离

将新合成的无孔硅胶二乙基氨基新型离子交换填料 (NPS-DEA)用于蛋白质的液相色谱分离。考察了流动相的pH值、盐浓度、流速及梯度程序对蛋白质分离的影响 ,并考察了蛋白质的质量回收率。实验结果表明 ,所得阴离子交换固定相的色谱性能良好。在梯度淋洗条件下 ,卵清蛋白、牛血清蛋白、胰岛素、γ-球蛋白、核糖核酸酶、溶菌酶获得了较好的分离。蛋白质的保留符合一般的保留值规律。柱填充床稳定 ,而柱负载较小 ,可用于高纯度的微量制备。     

单分散亲水两性离子交换树脂的制备及其在生物大分子分离中的应用

采用分散聚合与溶胀聚合相结合的方法及高分子溶液致孔技术, 成功地制备了粒径为5.0 μm大孔和超大孔结构的单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂, 并进行了结构表征. 将该树脂经胺化后再与1,3-丙磺酸内酯反应, 得到一种新型的两性离子交换(强阳-强阴型)高效液相色谱填料. 研究了该填料对标准蛋白分离性能及流动相中有机溶剂、 流速和pH值对蛋白保留的影响. 实验结果表明, 在流速为3 mL/min时, 采用线性梯度洗脱, 在4.0 min内可同时快速基线分离3种酸性和2种碱性蛋白.     

蛋白质在合成阳离子交换剂上的色谱特性研究

用国产材料按间接法合成了螯合型弱阳离子交换剂,详细研究了合成填料的色谱性能,并与商品柱的分离效能进行了比较;在宽温度范围内研究了蛋白质在弱阳离子交换系统中的色谱热力学,测定了蛋白质在色谱过程变性时的热力学参数 (△H0和△S0) 和补偿温度β,提出用标准熵变△S0判断蛋白质的构象变化和用△H0与△S0的补偿关系鉴定蛋白质各变体在色谱系统保留机理的同一性。考察了螯合型弱阳离子交换剂与金属离子的作用,研究了蛋白质在金属螯合色谱中的保留机理。     

Sinopak-s-DEAE高效弱阴离子交换色谱填料的研究

以多孔硅胶为基质,用改进的合成方法制备了Sinopak-s-DEAE高效弱阴离子交换色谱填。考察了反应条件对填料合成的影响,并以标准蛋白为样品进行了色谱行为的研究,结果表明：所制备的填料对蛋白质的分离性能良好,且对蛋白质的非特异性吸附小。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.