离子液体双水相溶剂浮选法分离/富集桑黄黄酮类成分

将亲水性离子液体氯化-1-丁基-3-甲基咪唑([C4mim]Cl)和K2HPO4形成的双水相体系与溶剂浮选结合,建立了分离/富集桑黄中总黄酮类成分的方法。考察了分相盐的种类和用量、样品量、溶液pH值、浮选时间和氮气流速对浮选效果的影响,并与双水相萃取进行比较。当浮选分相盐K2HPO4的质量浓度为50%、溶液pH=9.53、离子液体的用量为3 mL、浮选时间为50 min、氮气流速为30 mL/min时,浮选效率最佳,达到85.31%,富集倍数为8.59。离子液体双水相溶剂浮选法浮选效率高,富集倍数大,为中草药有效成分分离/富集提供了新方法。     

双水相浮选过程中青霉素的分离行为

基于双水相浮选技术(ATPF)分离富集水相中青霉素的方法,研究了双水相浮选过程中青霉素的分离行为.在常温下,2.5 g/L青霉素水溶液300 mL、初始pH 7、(NH4)2SO4浓度350 g/L、浮选溶剂为50%(w/w)PEG1000水溶液10 mL条件下,分别研究了青霉素在双水相浮选过程中的动力学行为和分离后的...     

聚乙二醇-硫酸铵双水相萃取次甲基蓝的研究

利用分光光度法研究了次甲基蓝在聚乙二醇-硫酸铵双水相体系的萃取行为,探索了质量配比(mPEc/m(NH4)2SO4)、温度和次甲基蓝的浓度对双水相及次甲基蓝萃取率(Y)的影响.实验表明:(1)在一定的温度和浓度下,随着mPEC/m(NH4)2SO4的减小,分配系数K( cup/clow)增加,萃取率Y略有减小;(2)在一定的质量配比和浓度下,分配系数K(cup/clow)随温度的升高而增大,但萃取率Y却基本保持不变;(3)在一定的质量配比和温度下,随着次甲基蓝浓度的增加,分配系数K(cup/clow)增大;萃取率Y略有增加.在mPEG/m( NH4) 2SO4为1.50∶1,c次甲基蓝=8.915×10-5mol/L、t=30℃的实验条件下,K(cup/clow)=22.14,萃取率(y)可达95.43％.     

聚合物/磷酸盐双水相分离乳清分离蛋白中α-乳白蛋白和β-乳球蛋白条件的优化

建立了基于聚(乙二醇-ran-丙二醇)单丁基醚(聚合物)与磷酸盐、氯化钠的双水相体系对乳清分离蛋白(WPI)中的α-乳白蛋白(α-LA)和β-乳球蛋白(β-LG)进行分离,并对其分离条件进行了优化.系统地研究了双水相体系pH值、聚合物与KH2PO4溶液体积比、NaC1添加量和WPI浓度对α-LA和β-LG的分离效果的影响,采用液相色谱法对α-LA和β-LG的分离效果进行评价.结果表明,聚合物/KH2PO4双水相体系pH=4.0,40％ (m/m)聚合物与15.5％ (m/m)KH2PO4的体积比为4 mL∶4 mL,NaCl添加量为0.40 g/10 mL,WPI浓度为1 mg/mL时,α-LA和β-LG分离效果最好,上相中α-LA的萃取率为98.2％,下相中β-LG的萃取率为96.6％.     

聚丙二醇-硫酸铵双水相萃取银杏黄酮

研究了银杏叶黄酮在聚丙二醇(PPG)400-(NH_4)_2SO_4双水相体系中的分配情况。探讨了单因素p H、PPG400质量分数、(NH_4)_2SO_4质量分数、料液比、温度、萃取时间对萃取率(Y%)和分配系数(K)的影响,并通过正交试验进一步优化双水相萃取条件。结果表明,各个因素对Y%和K影响为PPG400质量分数pH(NH_4)_2SO_4质量分数萃取时间萃取温度料液比。最佳萃取条件为p H 6、PPG400质量分数25%、(NH_4)_2SO_4质量分数15%、料液比1∶15、萃取温度40℃、萃取时间60min,黄酮萃取率达到98%以上。PPG400-(NH_4)_2SO_4双水相体系对银杏叶黄酮有较好的萃取效果。     

离子液体双水相技术萃取头孢呋辛酯及其机理探究

通过研究离子液体四氟硼酸1-丁基-3-甲基咪唑( [Bmim]BF4)-Na2-CO3双水相体系对头孢呋辛酯的萃取性能,建立了萃取环境水样中头孢呋辛酯的双水相法.考察了双水相体系组成及相关条件对萃取率的影响,并对其萃取作用力及萃取机制进行了探索.结果表明,Na2CO3用量为0.8～2.0 9,[Bmim]BF4用量为1～2 mL时,随着二者用量的增加,萃取率有所增加.与[Bmim]C1/Na2CO3双水相体系相比,[Bmim]BF4/Na2CO3双水相体系更适于萃取头孢呋辛酯.热力学参数AG°T＜0,AH°r＞0,△S°T＞0,说明萃取过程的主要推动力为疏水性相互作用.在最佳萃取条件下,用此方法萃取环境水样中的头孢呋辛酯,二次萃取率大于93％,重现性好.整个萃取过程快速、高效且无乳化现象.     

制备型高速逆流色谱分离纯化香菇多糖

利用高速逆流色谱仪,研究了双水相系统对香菇多糖的分离.溶剂系统为w(PEG1000):w(K2HPO4):w(KH2PO4):w(H2O)=0.5:1.25:1.25:7.0,在转速为500 r/min,流速为1.5 mL/min的条件下,成功分离了香菇多糖粗品(700 mg),得到LenⅠ(95 mg)、LenⅡ(45 mg)两个组分.用Sephadex G-100凝胶色谱柱检测纯度,结果显示:LenⅡ为单一峰,凝胶渗透色谱法测定; LenⅡ分子量为293 kDa;经酸水解后液相色谱分析表明,其单糖组成为葡萄糖和甘露糖,摩尔比为2.7:1; 红外光谱显示其具有多糖类的特征吸收峰.     

离子液体双水相萃取山楂黄酮和多糖的相行为研究

用分光度法研究了[Bmim]BF4/(NH4)2SO4双水相体系萃取山楂黄酮和多糖的相行为,考察了同时提取这两种组分时[Bmim]BF4的浓度、(NH4)2SO4的浓度、山楂的用量、超声萃取时间等因素对双水相的上下相体积以及分配系数的影响。结果表明:(1)离子液体浓度的增加,双水相的上、下相体积分别明显增大和减小。但黄酮和多糖在双水相中的分配系数仅有波动,均小于5%;(2)硫酸铵浓度的增加,双水相的上下相体积分别明显减小和增大。同时黄酮和多糖的分配系数均有较明显先降低后升高的趋势;(3)山楂质量的增减,不影响双水相的形成,但存在一个实验条件下的溶出饱和值,该值为0.15g,此时黄酮和多糖的分配系数最大;(4)超声萃取时间的延长或缩短,同样不影响双水相的形成,但存在对山楂有效成分达到饱和溶出的阈值,对于黄酮为25min,多糖为20min。     

一种用于鸡蛋中氯霉素残留测定的吡啶类离子液体双水相体系

建立了由亲水性离子液体N-乙基吡啶溴化盐([Epy]Br)和K2HPO4形成的双水相体系对鸡蛋中痕量氯霉素(CAP)检测的高效液相色谱方法.优化了离子液体[Epy]Br和K2HPO4成相的条件,研究了萃取CAP的最佳体系.采用混合溶液(pH=7磷酸盐溶液,NaCl溶液,甲醇)提取样品,离子液体双水相体系富集,V(甲醇):V(水)=30:70为流动相,流速1.0 mL/min,UV检测器,检测波长278 nm,柱温25 ℃,进样量20 μL.对鸡蛋中氯霉素残留进行了测定,在0.05～15 mg/L范围内,CAP的响应峰面积与其相应浓度呈良好相关性(r=0.9994).不同浓度的回收率为90.3%～101.7%,相对标准偏差为1.7%～2.6%.本该法检测鸡蛋中氯霉素残留具有干扰小、速度快、灵敏度高等优点.最低检出限为1 μg/kg.     

双水相手性萃取拆分扁桃酸外消旋体

研究了扁桃酸(MA)对映体在含β-环糊精(β-CD)手性选择剂的聚乙二醇(PEG)/(NH_4)_2SO_4双水相体系中的萃取分配行为.考察了pH、PEG和(NH_4)_2SO_4的质量分数、β-CD的浓度、MA的浓度与萃取温度等因素对拆分效果的影响.实验结果表明:双水相手性萃取具有很强的手性分离能力,β-CD对L-MA对映体的识别能力大于对D-MA对映体的识别能力;当温度为30℃、pH=1.0、PEG2000质量分数为30%、(NH_4)_2SO_4质量分数为20%、β-CD的浓度为0.008 mol/L、扁桃酸的浓度为0.05 mol/L时,分离因子(α)达到2.46,上、下相对映体过剩值(e.e.%)分别为42.13%和40.43%.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.