共查询到20条相似文献,搜索用时 390 毫秒
1.
2.
3.
4.
采用多糖类手性色谱柱,建立了(2-戊基-3-苯基-2,3环氧丙烷基)二苯基磷酸酯对映体的高效液相色谱手性拆分方法。考察了手性柱类型、流动相组成、流速、柱温等对手性拆分的影响,并对分离机制进行了探讨。结果表明,采用Chiralpak AS-H柱(250×4.6mm,i.d.,5μm),以正己烷-异丙醇(85∶15,V/V)为流动相,在柱温25℃,流速1.0mL/min,检测波长210nm的条件下,(2-戊基-3-苯基-2,3环氧丙烷基)二苯基磷酸酯对映体能达到完全分离,且稳定性和重复性好。该方法也适用于(2-戊基-3-苯基-2,3环氧丙烷基)二苯基磷酸酯类似物的手性拆分。 相似文献
5.
采用多糖类手性固定相,建立2-戊基-3-苯基-2,3-环氧丙醇对映体的高效液相色谱(HPLC)手性分析方法。考察了手性柱类型、流动相组成、流速及柱温对2-戊基-3-苯基-2,3-环氧丙醇对映体拆分的影响。结果表明,以Chiralcel OD-H色谱柱(25×0.46cm,5μm)分离,采用正己烷-异丙醇(V/V,90∶10)作流动相,在流速为0.8 mL·min-1,柱温25℃,检测波长210nm的条件下,2-戊基-3-苯基-2,3-环氧丙醇对映体能达到基线分离,且具有较好的重复性和稳定性,可用于对映体的拆分及质量控制。该方法也适用于2-戊基-3-苯基-2,3-环氧丙醇类似物质的手性拆分。 相似文献
6.
手性流动相添加剂法对两种手性化合物的直接拆分 总被引:3,自引:0,他引:3
以β-环糊精为手性流动相添加剂,于C8反相柱上建立了2种手性农药(包括杀菌剂己唑醇和杀虫剂SR-生物丙烯菊酯)对映体的高效液相色谱拆分方法。探讨了β-环糊精浓度、流动相pH、有机改性剂种类等因素对手性拆分的影响。结果表明:在流动相为β-环糊精水溶液、磷酸钠缓冲液(0.05mol/L)、乙腈、三乙胺(体积比50:30:20:0.5)条件下,己唑醇对映体在pH为7.4,β-环糊精溶液浓度为7mmol/L时,SR-生物丙烯菊酯对映体在pH为6.4,β-环糊精浓度为10.5mmol/L时得到最佳分离。 相似文献
7.
表层二氧化锆/硅基-CDMPC手性固定相的制备及联苯双酯类保肝药的直接拆分 总被引:1,自引:0,他引:1
用分子自组装的方法制备了表层纳米氧化锆包覆多孔微米硅球,得到的氧化锆 /硅胶微球用作高效液相色谱担体,本方法制备的担体具有氧化锆的表面特性并保 持了硅胶的颗粒均匀、表面积大、渗透性好的优点,可以制备大涂敷量的手性固定 相,以增加固定相的手性识别能力,以涂敷量为20%的纤维素-三(3,5-二甲基苯 基氨基甲酸酯)-氧化锆/硅胶手性固定相(CDMPC-coated ZrO_2/SiO_2)上,对 联苯双酯类保肝药物进行直接拆分,考察了流动相极性、第二种极性改性剂对样品 保留和拆分的影响;并对手性拆分机理进行了阐述,结果表明:CDMPC- ZrO_2/SiO_2手性固定相比CDMPC-ZrO_2具有更好的手性拆分能力。 相似文献
8.
以微晶纤维素和3,5-二甲基苯基氨基甲酸酯为原料,合成了纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC),将其分别涂敷于小孔硅胶(SG)、氨丙基化小孔硅胶(APS-SG)和介孔SBA-15微球上,制得3种手性固定相:SG@CDMPC(CSP1)、APS-SG@CDMPC(CSP2)及SBA-15@CDMPC(CSP3),正相条件下考察了12种中性或酸性手性化合物在自制手性固定相上的拆分效果,并与商品柱Chiralcel OD-H的拆分性能进行了对比。 6个手性化合物在CSP1上获得比在商品柱上更高的柱效,其中2个手性化合物获得比在商品柱上更高的分离因子和分离度,而CSP2和CSP3的拆分效果总体较CSP1和商品柱的差。 探讨了自制手性固定相对华法令的拆分和定量测定,华法令在CSP1上的检测限为10 μg/L,在0.05~5 g/L范围内线性关系良好。 相似文献
9.
建立了手性柱HPLC法测定盐酸贝那普利的中间体(R)-α-羟基苯丁酸乙酯中的(S)-α-羟基苯丁酸乙酯。采用Chiralcel OD-H色谱柱,流动相正己烷-异丙醇(体积比90:10),流速1.0mL/min,检测波长254nm,进样体积20μL,按外标法以峰面积计算(R)-α-羟基苯丁酸乙酯中的(S)-α-羟基苯丁酸乙酯的含量。(S)体的线性范围5.5~23.8μg/mL,检出限0.47μg/mL(S/N=3),回收率为96%~103%,精密度RSD为2.1%(n=6)。 相似文献
10.
在水-环己烷微乳体系中制备高比表面积氧化锆 总被引:5,自引:0,他引:5
在水/TritonX-100/环己烷/正己醇微乳体系中合成了氧化锆粉末,经过450℃氧气中焙烧和400℃抽真空处理后,获得了比表面积高达464m2/g的氧化锆粉末.X射线衍射测试表明,该化合物最初为无定形氧化锆,经450℃焙烧3h后开始出现四方晶相和少量的单斜晶相氧化锆,随着焙烧温度升高至900℃,单斜晶相增加,但四方晶相仍是主要的.在600℃以下,添加氧化锰会阻止单斜晶相氧化锆的出现,使所制备的15%MnO2-ZrO2具有较高的可逆吸附氮氧化物的能力. 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.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
13.
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. 相似文献
14.
Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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
15.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
16.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
17.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
18.
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
19.
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
20.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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