铜（Ⅱ)-氟喹诺酮类抗生素螯合物与虎红体系的吸收和共振瑞利散射光谱及其分析应用研究

在pH 4.2~4.8的B-R缓冲介质中,莫西沙星（MXFX)和加替沙星（GTF)等氟喹诺酮类抗生素（FLQs)能与铜（Ⅱ)形成螯合阳离子,进一步与虎红（Tf)阴离子通过静电引力和疏水作用形成FLQs∶Cu（Ⅱ)∶Tf为1∶1∶1的离子缔合物,体系反应导致共振瑞利散射（RRS)显著增强并出现新的RRS光谱。两种药物的反应产物具有相似的光谱特征,最大RRS峰位于373 nm处,并在590 nm处有1个较小的散射峰。在373 nm处一定浓度的抗生素与散射增强（ΔI)成正比,MXFX和GTF的线性范围分别为0.031~7.8 mg/L和0.029~9.0 mg/L。据此建立了测定氟喹诺酮类药物的新方法,方法用于胶囊和人尿液中FLQs的测定并取得满意结果。同时对反应机理及RRS增强原因进行了讨论。     

Absorption Spectra and Resonance Rayleigh Scattering Spectra of Cu(Ⅱ)-Fluoroquinolone Chelates with Tetrachlorotetraiodo-fluoresceindisodium Salt System and Their Analytical Applications

在pH 4.2～4.8的B-R缓冲介质中,莫西沙星(MXFX)和加替沙星(GTF)等氟喹诺酮类抗生素(FLQs)能与铜(Ⅱ)形成螯合阳离子,进一步与虎红(Tf)阴离子通过静电引力和疏水作用形成FLQs∶Cu(Ⅱ)∶Tf为1∶1∶1的离子缔合物,体系反应导致共振瑞利散射(RRS)显著增强并出现新的RRS光谱.两种药物的反应产物具有相似的光谱特征,最大RRS峰位于373 nm处,并在590 nm处有1个较小的散射峰.在373 nm处一定浓度的抗生素与散射增强(△I)成正比,MXFX和GTF的线性范围分别为0.031 ～7.8 mg/L和0.029～9.0 mg/L.据此建立了测定氟喹诺酮类药物的新方法,方法用于胶囊和人尿液中FLQs的测定并取得满意结果.同时对反应机理及RRS增强原因进行了讨论.     

盐酸吖啶黄-脱氧核糖核酸反应体系的共振瑞利散射及其应用

研究了盐酸吖啶黄与脱氧核糖核酸(DNA)之间的共振瑞利散射(RRS)增强作用,提出了共振瑞利散射技术测定核酸的方法。在pH 6.4的B-R缓冲溶液中,盐酸吖啶黄与脱氧核糖核酸结合使溶液共振瑞利散射强度增强,其最大散射峰位于505 nm处,而在330 nm波长处有一稍弱的散射峰。DNA质量浓度在0.04~0.80 mg.L-1范围内,与RRS强度呈线性关系,检出限(3S/N)为0.023 mg.L-1。应用于测定合成样品中DNA含量并测得回收率为98.0%~104.0%。初步探讨了反应机理,盐酸吖啶黄与DNA间的相互作用包含有静电引力、π-π堆积力。     

氯化铁-铁氰化钾体系共振瑞利散射法测定白藜芦醇

在pH 1.8的B-R缓冲溶液中,白藜芦醇(RES)使[Fe(CN)6]3-还原为[Fe(CN)6]4-,后者与铁(Ⅲ)反应生成普鲁士蓝,其共振瑞利散射(RRS)急剧增强。于最大RRS峰314nm处测定其散射强度IRRS,扣除空白溶液的散射强度,RES的质量浓度在0.05~5.0mg·L-1范围内与散射强度差ΔI呈线性关系。RES的检出限(3s/k)为15μg·L-1。应用此方法测定了葡萄叶和虎杖中RES的含量。所得结果与高效液相色谱法测得的结果相符。用标准加入法进行回收试验,测得回收率在96.0%~104%之间。测定值的相对标准偏差(n=5)在1.7%~4.3%之间。对反应体系的RRS增强的机理也进行了探讨。     

硫酸卡那霉素-固绿体系的共振瑞利散射光谱及其分析应用

提出了共振瑞利散射法(RRS)测定硫酸卡那霉素(KANA)的方法。在p H为4.56~6.09的B-R缓冲溶液中,固绿与KANA结合生成离子缔合物,使溶液共振瑞利散射(RRS)增强,其最大散射峰位于709 nm,另在463 nm、370 nm有两个较弱的散射峰。KANA的浓度在0.08~1.6 mg·L~(-1)范围内,与RRS强度有良好的线性关系,对KANA的检出限(3σ)达0.024 mg·L~(-1)。研究了适宜的反应条件和影响因素,表明该方法灵敏、稳定。用于硫酸卡那霉素注射液的测定,回收率为96.5%~103.0%。     

氟喹诺酮类抗生素与赤藓红的共振瑞利散射光谱研究及其分析应用

在Ph4.0～5.0的BR缓冲介质中,赤藓红(Ery)与莫西沙星(MXFX)和加替沙星(GTF)等氟喹诺酮类抗生素(FLQs)相互作用形成1:1离子缔合物,体系反应导致共振瑞利散射(RRS)显著增强并出现新的RRS光谱.两种药物的反应产物具有相似的光谱特征,最大散射波长位于568nm处,并在342nm和378nm处有2个较小的散射峰.在342nm处一定浓度的抗生素与散射增强成正比,两种氟喹诺酮类药物的线性范围分别是0.02～2.7μg/mL(MXFX)和0.06～10.2μg/mL(GTF).据此建立了测定氟喹诺酮类药物的新方法,已用于胶囊和人尿液中的FLQs测定,并对反应机理和RRS增强的原因作了讨论.     

测定新药雷洛昔芬的曲利本红共振瑞利散射法

在 pH1.4的醋酸钠 -盐酸缓冲溶液中,曲利本红和雷洛昔芬自身的共振瑞利散射(RRS)均很微弱,只在470nm处有很弱的散射信号,但当它们结合形成离子缔合物后,RRS大大增强,而且产生了新的散射峰,在310～530nm范围内呈现高的散射强度,且以396nm处的散射信号最强 ;RRS强度在0～6.3mg·L-1的范围内与雷洛昔芬的质量浓度成正比 ;方法灵敏度高,对雷洛昔芬的检出限(σ=3)为10.9μg·L-1,而且选择性、稳定性俱佳,由此建立了一种用RRS法测定痕量雷洛昔芬的方法 ;方法用于Evista片中雷洛昔芬含量的测定,结果令人满意     

甲基紫硫酸软骨素共振瑞利散射光谱及其应用

在Britton-Robinson缓冲介质(pH9.37)中硫酸软骨素与甲基紫反应形成离子缔合物时,共振瑞利散射(RRS)强度会明显增强,其最大RRS峰位于505和661 nm处。本文对反应的最佳条件、影响因素、硫酸软骨素浓度与RRS强度的关系进行了研究,建立起一种快速、简便、灵敏的测定硫酸软骨素的方法。本法在661和505 nm测定波长处的线性范围均为:0.15~0.90 mg/L,其检出限分别为0.019 mg/L(505 nm)和0.043mg/L(661 nm)。该法应用于针剂中硫酸软骨素的测定,结果满意。     

卡托普利-维多利亚蓝B体系的共振瑞利散射光谱及应用

建立了快速测定卡托普利的共振瑞利散射法,探讨了共振瑞利散射光谱特征和共存物质的影响。在弱碱性溶液中,卡托普利与维多利亚蓝B反应生成蓝色二元离子缔合物,使体系的共振瑞利散射(RRS)信号显著增强,最大RRS峰位于356nm,体系的RRS增强程度△IRRS与0.004~0.22mg·L~(-1)范围内的卡托普利的质量浓度呈线性关系,检出限为0.0035 mg·L~(-1)。方法用于药物中卡托普利的测定,回收率为99.21~102.3%,相对标准偏差RSD(n=5)为1.8~2.4%。     

吐温-20敏化甲基蓝-蛋白质散射光谱研究与应用

在非离子表面活性剂吐温-20存在下,甲基蓝与蛋白质作用形成离子缔合物,使共振瑞利散射(RRS)急剧增强.研究了相应的光谱特征、影响因素和适宜的反应条件.在pH=4.0和离子强度0.5 mmol\5L-1的条件下, 甲基蓝与蛋白质作用在347 nm波长处产生特征RRS,吐温-20进一步敏化该RRS.不同蛋白质在一定浓度范围内与吐温-20敏化的散射强度呈线性关系,检出限在12.3～30.1 μg\5L-1范围内.方法用于合成样品以及实际生物样品中蛋白质含量的测定, 结果满意.     

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.     

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.     

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.