羟丙基-β-CD包结荧光法测定大黄素的研究

用荧光光谱研究了羟丙基-β-环糊精(HP-β-CD)与大黄素间的相互作用,发现两者可形成1∶1的超分子包合物,大黄素包合物在λex/λem=467/547 nm处发射荧光,包合常数为85.18 L/mol.据此建立了羟丙基-β-环糊精增敏测定大黄素的荧光分析新方法.在0.32～3.24μ-g/mL浓度范围内,大黄素的荧...     

5-马来酰亚胺-2-(间马来酰亚胺基苯基)苯并噁唑用于荧光光度法直接测定还原型谷胱甘肽的研究

以5-马来酰亚胺-2-(间马来酰亚胺基苯基)苯并噁唑(DMPB)为荧光试剂,建立了在一定量半胱氨酸(Cys)存在下荧光光度法直接测定还原型谷胱甘肽(GSH)的新方法。研究表明,DMPB荧光很弱,其结构中的两个马来酰亚胺基团都能与GSH或Cys发生反应,生成具有强荧光的产物。并且DMPB与GSH或Cys的生成物(分别称为DMPB-GSH和DMPB-Cys)的最大荧光波长会以不同的速率从eλx/eλm=302/372nm红移至eλx/eλm=310/430 nm,最终均在eλx/eλm=310/430 nm处稳定。在pH 7.0的Na2HPO4-KH2PO4缓冲溶液中和35℃下,DMPB与GSH或Cys反应15 min后,生成的DMPB-GSH的最大荧光波长为eλx/eλm=302/372 nm,且最大荧光强度可以稳定1h,而DMPB-Cys的最大荧光波长为eλx/eλm=310/430 nm,且荧光较弱。利用这一差别,我们选择在eλx/eλm=302/372 nm的荧光波长下测定GSH,完成了0.3倍(Cys∶GSH,摩尔比)Cys存在下对GSH的直接测定,方法线性范围为4.0×10-8~9.6×10-7mol.L-1,检出限(S/N=3)为1.5×10-9mol.L-1。用该法测定了人全血中的GSH,结果令人满意。     

同步扫描-双波长荧光分光光度法同时测定三种儿茶酚胺类神经递质

提出了用同步扫描-双波长荧光分光光度法同时测定肾上腺素(EP)、去甲肾上腺素素(NEP)和多巴胺(DA)3种儿茶酚胺类神经递质.试验表明:荧光检测宜选定发射波长(λen)与激发波长(λex)的波长差为70 nm(△λ=λem-λex)的条件下进行同步扫描.在λem为385.0 nm时DA的荧光信号不受EP和NEP的干扰,而EP和NEP相互的干扰,采用双波长荧光检测模式可消除.选择测定NEP的波长对为470.0 nm(λem,1)和531.8 nm(λem,2),测定EP的波长对为500.0 nm(λ'em,1)和445.6 nm(λ'em,2).测得荧光强度与3种儿茶酚胺浓度在320 μg·L-1(EP),640 μg·L-1(NEP)及160μg·L-1(DA)内呈线性关系,检出限(3σ/k)依次为0.20,0.97,0.73 μg·L-1.     

汞(Ⅱ)-邻菲啰啉-水杨基荧光酮荧光猝灭体系的研究及应用

在pH 8.0～9.0的KH2PO4-Na2B4O7缓冲溶液中,在乳化剂OP存在下,溶液中的汞(Ⅱ)与邻菲啰啉(o-phen)和水杨基荧光酮(SAF)反应生成一多元配合物,使水杨基荧光酮溶液的荧光猝灭,据此建立了测定痕量汞的荧光分析法.体系的激发波长λex=365.0 nm,发射波长λem=580 nm.汞的浓度在0～80μg/L范围内与△F存在良好的线性关系.方法的检出限为1.04 ng/mL.对1μgHg(Ⅱ)进行11次平行测定,其相对标准偏差RSD=1.9%,配合物的组成比为Hg(Ⅱ)o-phenSAF=122.方法用于环境水样中痕量汞的测定.     

N-(安替比林-4-基)-香豆素-3-甲酰胺的合成及其光学性能

以香豆素-3-甲酰氯和4-氨基安替比林为原料,采用传统加热或无溶剂室温研磨法合成了一种新型的含安替比林基香豆素-酰胺类化合物——N-(安替比林-4-基)-香豆素-3-甲酰胺(3),其结构经1H NMR和FT-IR表征。用UV-Vis和荧光光谱研究了3的光学性能。结果表明:3的λmax位于290 nm,334 nm;在THF中,3的λem位于319 nm(λex=283 nm);固体荧光的最大发射波长位于471 nm(λex=295 nm)。     

4-(N-咔唑基)查尔酮的合成及其光学性质

4-N-咔唑基苯甲醛和苯乙酮经aldol反应合成了一种新型含咔唑基查尔酮——4-(N-咔唑基)查尔酮(2),其结构经1H NMR,IR,MS和元素分析表征。运用UV-Vis和单光子荧光光谱研究了2的光学性质。结果表明:2的λmax位于360 nm和320 nm附近;2在CH2Cl2和DMF中具有良好的荧光发射能力,λem位于520 nm。     

铁(Ⅲ)-过氧化氢-水杨基荧光酮-溴化十六烷基三甲铵荧光猝灭反应及其应用

在pH 3.1～5.2的HCl-NaAc缓冲介质中,溶液中的铁(Ⅲ)与过氧化氢(H2O2),水杨基荧光酮(SAF)和溴化十六烷基三甲铵(CTMAB)反应产生一多元混合络合物,使水杨基荧光酮溶液的荧光明显猝灭,据此建立了测定痕量铁的荧光猝灭分析法.该体系的激发波长λex=435.8 nm,发射波长λem=540 nm.铁的浓度在2～100 μg/L范围内有良好的线性关系;方法的检出限为0.41 μg/L.该方法灵敏度高,操作简便,用于天然水和人发样中微量铁的测定,结果满意.     

邻苯二甲酸二丁酯免疫检测 Ⅰ.人工抗原的制备及表征

通过保留丁酯基结构和在芳环上引入氨基取代基合成了一种邻苯二甲酸二丁酯半抗原衍生物4-氨基邻苯二甲酸二丁酯，通过1^H NMR、IR和UV确证了结构，其中4-硝基邻苯二甲酸二丁酯的2个紫外吸收峰分别为：λ1=212 nm，λ2=258 nm；4-氨基邻苯二甲酸二丁酯的2个紫外吸收峰分别为：λ1=226 nm，λ2=288 nm。半抗原衍生物通过重氮化反应与BSA偶联，得到人工抗原，经荧光光谱（λex=307nm，λem=468nm）、体系颜色变化和免疫实验确证偶联成功，抗原结合比为13：1，为进一步的抗体制备和免疫分析提供可靠的免疫原。     

新型蒽类离子液体的合成及其荧光性能

设计并合成了五个含蒽环的新型离子液体(1a～1e),其结构经NMR,IR和MS表征.荧光光谱分析结果表明,1具有很强的荧光性能,λabmax =257 nm,λcxmax =423 nm.     

微波溶样肉桂基荧光酮和表面活性剂连续荧光测定葡萄酒中铁和钴

观察到肉桂基荧光酮(略作CF)在pH≈8与Fc(Ⅲ)配位后荧光增强,CPB的加入使荧光更强,络合物与试剂荧光强度之比F_(FeR)/F_R随0～0.01μg/ml Fe(Ⅲ)线性变化,λ_(ex)=410nm,λ_(ex)=480nm;而CF在pH≈10与Co(Ⅲ)配位后荧光却减弱,乳化剂OP存在时使试剂荧光增强,若以荧光熄灭Co(Ⅲ)灵敏度便提高,试剂与络合物荧光强度之比F_R/F_(CoR)对0～0.016 μg/ml Co(Ⅲ)呈直线关系,λ_(ex)=300nm,L_(em)=352nm。控制化学条件和激发、发射波长,可不经分离测定葡萄酒(微波溶样)中铁和钴。     

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.     

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.