键合纤维素(4-甲基苯甲酸酯)手性固定相的制备及其手性拆分

采用包夹聚合法,将硅小球同硅烷化试剂反应制得乙烯基硅胶,然后将该乙烯基硅胶同经十一烯酰氯、4-甲基苯甲酰氯衍生的纤维素共聚,制备出含不同官能团的聚合物包夹硅基的键合型纤维素(4-甲基苯甲酸酯)类手性固定相。分别以正己烷异丙醇、正己烷四氢呋喃为流动相,对此键合型手性固定相的手性识别能力进行了评价。为了与同类型的涂敷型纤维素(4-甲基苯甲酸酯)手性固定相作比较,合成了涂敷型纤维素(4-甲基苯甲酸酯)手性固定相。结果表明,键合型纤维素(4-甲基苯甲酸酯)手性固定相具有一定的手性识别能力,可以拆分所研究的6种手性化合物中的4种。     

硅基寡聚砜型新型HPLC固定相的制备及其色谱性能评价

以硅小球为基质,γ-氨丙基三乙氧基硅烷,环硫乙烷和过氧乙酸为改性剂,制备了硅基寡聚砜型新型液相色谱固定相。在活化的硅小球表面引入氨基,制得氨基键合相,然后氨基键合相与环硫乙烷进行开环聚合反应,在氨基键合相表面引入巯基和硫醚基,最后用过氧乙酸将其分别氧化为磺酸基和砜基,制得磺酸乙基聚乙砜基胺丙基固定相。采用元素分析进行表征,通过S和N的摩尔比确定固定相表面胺基,砜基和磺酸基的比例。在不同条件下,分别选用碱性化合物、中等极性和弱极性化合物等13种溶质对该固定相的色谱性能进行评价,证明该固定相兼有疏水作用,亲水作用和静电作用。用于实际样品测定,该固定相呈现出良好的分离选择性和较广的应用范围。     

新型高效液相色谱酰胺键合固定相的制备与评价

将YWG-80硅胶和3-氨基丙基三甲氧基硅烷反应后与2-壬基丁二酰氯反应制得一种新型双齿酰胺键合固定相(BABSP-2)。采用元素分析和傅里叶变换红外光谱表征了键合相;用芳香族化合物溶质和甲醇-水二元流动相,考察了键合相的疏水选择性和亲硅醇基活性;评估了在酸性条件下(pH2.5)的水解稳定性。结果表明：BABSP-2能有效抑制残留硅醇基活性,并具有可比的疏水选择性和较好的水解稳定性。     

含二茂铁核的硅有机衍生物的合成

合成了一系列含二茂铁核的硅有机衍生物.试图从环戊二烯基三甲基硅烷与FeCl₂在二乙胺存在下制取1,1'-双(三甲基硅烷基)二茂铁,由于Si-C键的断裂,未获预期产物而得二茂铁. 为了合成双有机硅基二茂铁,采用了两种方法.方法之一是从1,1'-二茂铁二钠与相应的三烷基氯硅烷反应制得1,1'-双(三甲基硅烷基)二茂铁、1,1'-双(三丁基硅烷基)二茂铁和1,1'-双(二甲基苯基硅烷基)二茂铁.为了取得单取代硅烷基二茂铁,采用二茂铁锂,但一般得单和双取代衍生物的混合物,它们很难分离;如减少有机氯硅烷用量,则可得纯的单取代乙烯基二乙基硅烷基二茂铁.另一方法是将三甲基-γ-氯丙基硅烷的格氏试剂与二乙酰基二茂铁反应制得含二茂铁核的双叔醇.     

硅有机化合物——Ⅲ.对(三甲硅基)甲苯的衍生物

从对(三甲硅基)甲苯开始,将苄基中的甲基溴化成溴甲基,从而制得对(三甲硅基)苄基取代的乙酰乙酸乙酯,丙二酸乙酯和氰化物等,应用Sommlet反应制得醛. 将对(三甲硅基)甲苯氧化成相应的羧酸后,用亚硫酰氯处理,加入氨水即得对(三甲硅基)苯甲酰胺.应用类似方法,制得对(三苯硅基)苯甲酸、二甲基二(对羧基苯基)硅烷和二苯基二(对羧基苯基)硅烷的一些酰胺和酯.在用亚硫酰氯处理时,未发现硅-碳键的断裂现象.     

乳胶附聚型阴离子交换固定相的制备及表征

以烯丙基缩水甘油醚（AGE）为乳胶聚合单体,制备了一种乳胶附聚型阴离子交换固定相。通过无皂化乳液聚合法,以AGE和苯乙烯（ST）为共聚单体制备AGE-ST共聚乳胶。将该乳胶季铵化后附聚在磺化的聚苯乙烯-二乙烯苯（PS-DVB）微球表面,制备一种乳胶附聚型阴离子交换色谱固定相。通过扫描电镜（SEM）、傅里叶红外光谱（FT-IR）和元素分析（EA）等对该乳胶附聚型阴离子交换色谱固定相的理化性质进行表征,结果显示季铵化的AGE-ST共聚乳胶成功附聚在磺化的PS-DVB微球表面,并通过分离常规阴离子和有机酸对制得的阴离子交换剂的色谱性能进行评价。AGE以其良好的pH耐受性和活泼的反应活性为离子交换色谱固定相的制备提供一个新的选择。     

苯基异氰酸酯环糊精键合相的制备及色谱行为的研究

以ＤＧ－２硅胶为载体,３－氨基丙基三乙氧基硅烷作为烷胺化试刑,选择己二酰氯为空间臂给体,将苯基异氰酸酯β－环糊精键合至ＤＧ－２上。用三申基氧硅烷对制得的键合相进行末端封闭,并对末端封闭的键合相（相Ⅰ）和未进行末端封闭的键合相（相Ⅱ）的ＭｃＲｅｙｎｏｌｄｓ常数进行了研究。相Ⅰ与相Ⅱ的常数差值可以认为是活性氢贡献的。还测定了二甲苯异构体在相Ⅰ和相Ⅱ上的焓值与熵值。在相Ⅰ上的对、间和邻二甲苯的焓变值ΔＨ分别为－３３．８,－３９．８和－４５．６ｋＪ·ｍｏｌ￣（－１）,其分离程度明显优于相Ⅱ。     

β-环糊精-对氯苯基氨基甲酸酯手性固定相的色谱行为

合成了β-环糊精-对氯苯基氨基甲酸酯衍生物,并分别涂敷于氨丙基硅胶和硅胶表面,制得两种涂敷型β-环糊精-对氯苯基氨基甲酸酯手性固定相(CSP1,CSP2),并以!-异氰酸酯丙基三乙氧基硅烷为连接剂将此衍生物键合于硅胶表面制得同类型键合手性固定相(CSP3)。自制CSPs具有较好的手性识别能力。CSP3在多模式流动相组成下对21个手性样品呈现出不同的手性分离能力。此外,CSP2和CSP3对硝基苯酚的邻、间、对位置异构体也表现出很好的分离能力(分离度R4)。     

硅胶涂敷正相色谱填料的制备及应用

在大孔硅胶表面键合乙烯基硅烷化试剂,然后与甲基丙烯酸环氧丙酯、甲基丙烯酸乙二醇双酯共聚,制得聚合物涂敷硅胶,其表面经一步水解即可得到正相高效液相色谱填料,考察了该填料对苯的衍生物及吡啶等有机化合物的分离情况.实验结果表明,硅胶涂敷正相色谱柱对中性、酸性和碱性化合物均具有良好的色谱分离性能.     

硅基高交联磺化PS-DVB固定相的混合模式色谱性能考察

对自制的硅基高交联磺化PS-DVB混合模式反相强阳离子交换固定相的色谱性能进行了考察。通过改变流动相条件:在反相色谱中,分离了5种疏水性化合物;在离子交换色谱中,分离了4种碱性有机化合物。考察了流动相中缓冲盐浓度、p H和乙腈浓度对溶质保留时间的影响。结果表明,该固定相既具有强阳离子交换作用,又兼有疏水相互作用。通过改变色谱分离模式,可实现亲水性或疏水性化合物的分离。可作为现有液相色谱模式的一种补充,为复杂样品的分离提供技术参考。     

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.     

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.     

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.     

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.     

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.     

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.     

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.