高效液相色谱法同时测定血清和尿中厚朴酚与和厚朴酚

 建立了大鼠服用厚朴提取物后的血清中及尿中厚朴酚与和厚朴酚的高效液相色谱测定法。色谱柱填料为SpherisorbC18,流动相为甲醇-水-冰醋酸(体积比为70∶30∶1),UV检测波长为294nm,灵敏度0.005AUFS。样品用甲醇沉淀蛋白,上清液酸化后用乙酸乙酯-乙醚萃取,然后测定其中的药物浓度。血清和尿中的药物浓度与峰面积的线性关系良好,线性范围分别为0.05～2mg/L(厚朴酚)、0.025～1mg/L(和厚朴酚);精密度和重现性良好。血清中厚朴酚与和厚朴酚的平均加样回收率分别为95.6%(RSD=3.85%)和93.8%(RSD=3.95%),尿中分别为96.0%(RSD=3.83%)和94.9%(RSD=3.54%)。     

厚朴酚、和厚朴酚基态与激发态的电离常数及光谱性质差异的研究

通过对比厚朴酚、和厚朴酚的紫外光谱和荧光光谱在pH为-0.3 ～14.7时的变化情况,发现二者的光谱性质存在显著差异,从基态、激发态的电离平衡解释了其原因,探讨了取代基异构对厚朴酚与和厚朴酚基态、激发态电离平衡的影响.实验发现,厚朴酚具有较强的光酸性,水溶液中,当pH＞0时,厚朴酚只显示出1价阴离子HA-·的发射(λem=400 nm),采用荧光滴定法得到厚朴酚基态、激发态的电离常数分别为:pKa1·=0.57,pKa1=7.54、pKa2=14.38.而和厚朴酚的光酸性较厚朴酚小6个pK单位,其吸收和荧光光谱随pH的变化情况较厚朴酚复杂,采用荧光滴定法测定其pKa1·约为6.5.     

高速逆流色谱分离制备厚朴的有效成分厚朴酚与和厚朴酚

建立了高速逆流色谱分离制备厚朴的有效成分厚朴酚与和厚朴酚的新方法,溶剂系统为石油醚-乙酸乙酯-甲醇-1％醋酸(5：5：7：3,V／V),上相为固定相,下相为流动相。从100mg厚朴粗提物制得和厚朴酚33．3mg,厚朴酚19．5mg,经高效液相色谱分析,纯度均大于99．5％,其化学结构由^1H NMR和^13C NMR鉴定。     

二阶导数同步荧光光谱法同时直接测定厚朴酚及和厚朴酚

研究了厚朴酚与和厚朴酚及其混合溶液的二阶导数同步荧光光谱,结果两者的二阶导数同步荧光光谱得到完全分离,消除了彼此间的干扰,据此建立了一种二阶导数同步荧光光谱法同时直接测定混合物中厚朴酚与和厚朴酚的新方法.厚朴酚与和厚朴酚的线性范围分别为2.8～500.0 μg/L和4.3～560.0 μg/L;检出限分别为0.84和1.30 μg/L,回收率分别为94.65%～105.58%和95.09%～104.51%; 相对标准偏差均低于4.08%.本方法用于同时直接测定厚朴药材及其提取物中厚朴酚与和厚朴酚含量,结果令人满意.     

新型厚朴酚2-甲亚胺衍生物的合成及其生物活性

以厚朴酚为原料,通过Reimer-Tiemann法,在其苯环羟基邻位引入甲酰基后,分别与甘氨酸、谷氨酸、精氨酸及对氨基苯磺酰胺反应合成了4个单取代、1个二取代新型厚朴酚2-甲亚胺衍生物(3a~3d和4),其结构经UV-Vis, ¹H NMR, IR, MS和元素分析表征。生物活性研究结果表明： 2-(N-甘氨酸)-厚朴酚甲亚胺(3a)对成肌细胞的毒性较大;2-［N-(4-氨磺酰苯基)］-厚朴酚甲亚胺(3d)浓度为64 μmol·L^-1时,对CYP2D6和CYP1A2的抑制率分别为42.9%和36.8%。     

三维荧光光谱结合二阶校正算法测定人体血浆和厚朴药材中的厚朴酚及和厚朴酚

利用三维荧光光谱与化学计量学二阶校正算法相结合, 直接测定人体血浆中和厚朴药材中的厚朴酚及和厚朴酚. 采用平行因子分析(PARAFAC)算法解析所得两种物质的回收率分别为(99.5±2.6)%和(90.2±1.8)%. 采用交替三线性分解(ATLD)算法解析, 当组分数N取3时, 回收率分别为(104.2±3.2)%和(98.7±4.0)%; 当N取4时, 回收率分别为(102.7±2.9)%和(99.0±4.6)%. 同时用该方法对厚朴药材中的厚朴酚及和厚朴酚进行快速定量测定, 结果令人满意. 实验结果表明, 此法可用于复杂试样中未知干扰共存下厚朴酚及和厚朴酚的同时测定.     

溶剂浮选-紫外分光光度法测定厚朴中总厚朴酚

建立了一种测定厚朴中总厚朴酚的新方法,即采用溶剂浮选法分离富集厚朴中的总厚朴酚,用紫外分光光度法测定其含量。考察了浮选溶剂、试液pH、氮气流速、浮选时间及电解质NaCl等因素对浮选效果的影响,优选出最佳浮选条件。采用所述方法对不同产地厚朴样品中总厚朴酚含量进行测定,样品加标回收率为94.9%-100.8%,RSD为2.8-4.1%。     

大体积进样-逆电渗流堆积-毛细管区带电泳分离测定厚朴酚、绿原酸及咖啡酸

运用大体积进样-逆电渗流堆积-毛细管区带电泳分离测定了厚朴酚、绿原酸和咖啡酸。采用未涂层熔融石英毛细管(50 cm×50μm i.d.,有效柱长36 cm)分离;紫外检测波长为220 nm,运行缓冲液为40mmol/L四硼酸钠-20 mmol/L磷酸氢二钠(pH 9.0),分离电压16 kV,电动进样电压-12 kV,进样时间356s时达到最佳的分离效果。在优化条件下,上述3种化合物均在20 min内出峰,峰面积的RSD均小于4%。检出限分别为184.2、36.07、77.99 ng/L。将该法用于清肝利胆口服液中厚朴酚、绿原酸和咖啡酸的分离测定,结果满意。     

厚朴酚与人血清白蛋白的相互作用研究

利用荧光光谱、CD和FTIR技术研究了模拟生理条件下厚朴酚与人血清白蛋白的相互作用,计算了反应的结合常数、结合位点数和热力学参数。厚朴酚在人血清白蛋白上的结合位置与色氨酸残基间的距离为2.34 nm。分子模型研究表明,厚朴酚与HSA在亚结构域IIA结合,二者间的作用力主要为疏水作用。CD结果表明,厚朴酚与HSA的键合使HSA中α-螺旋结构含量从46.6%降到39.9%。     

基于羟基化酞菁锌-石墨烯纳米材料的和厚朴酚电化学传感器的构建及其应用

通过非共价作用制备了可溶性四羟基酞菁锌-石墨烯纳米复合材料,并将其应用于构建新型高灵敏度和厚朴酚电化学传感器.由于水溶性四羟基酞菁锌和石墨烯的协同作用,显著提高了纳米复合材料的比表面积和导电性,增强了和厚朴酚的电化学响应.在最优实验条件下测定,和厚朴酚在0.01～1.0μmol/L和1.0～100 μmol/L范围内呈...     

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.