儿茶酚在预活化聚酰胺膜多酚氧化酶电流传感器上的响应特性

本采用预活化聚酰膜固定多酚氧化酶并与浸蜡石墨极组合成传感器，测定儿茶酚的线范围２．×１０－７－１．２５×１０＾－５ｍｏｌ／Ｌ。检出限１．５×１０＾－７ｍｏｌ／Ｌ。酶的固定时间仅需１－２ｍｉｎ，５个月之后被固定酶的活性未见下降，活性酶膜的制备，贮存，替换均很方便，对传感器的机理进行了探讨。     

甲硫富瓦烯为介体的碳纤维束葡萄糖氧化酶微电极的研究

本研究了一种将电子介体四硫富瓦烯（ＴＴＦ，Ｔｅｔｒａｔｈｉａｆｕｌａｌｅｎｅ）引入葡萄糖氧化酶微电极的新方法，制成了ＴＴＦ为介体的碳纤维束葡萄氧化酶微电极。该电极制作简单，响应迅速，灵敏，电极寿命可达１５天。葡萄糖浓度在１．０×１０＾－＾４－１．５×１０＾－＾３ｍｏｌ／Ｌ范围内有线性关系，检出限为７×１０＾－＾５ｍｏｌ／Ｌ。用于人体血样中葡萄糖测获得满意结果。     

铁的单点络合滴定法研究

本研究了Ｆｅ＾３＋的单点络合滴定法，导出了定量关系式，比较了以铂电极为指示电极和以ＰＶＣ膜四氯络铁（Ⅲ）阴离子电极为指示电极时电位测量的稳定性及所得的分析结果。在Ｆｅ＾３＋浓度为１．０００×１０＾－３ｍｏｌ／Ｌ时，１８次实验的平均值为１．０２×１０＾－４ｍｏｌ／Ｌ，相对偏差小于１．７％；Ｆｅ＾３＋在５．０×１０＾３ｍｏｌ／Ｌ以上时，相对偏差小于０．１％；其浓度小于１０＾－３ｍｏｌ／Ｌ而大于５×１     

醋酸纤维膜固定过氧化氢酶电极的研究

本将过氧化氢酶与经活化处理的醋酸纤维膜共价固定，并与氧电极偶合，研制成静态和流通二种过氧化氢生物电极。研究了醋酸纤维膜的活化、酶的固定化、测试介质等有关的实验条件和参数。测得静态和流通二种电极响应的线性范围分别为６．７×１０＾－５￣２．０×１０＾－３ｍｏｌ／Ｌ和１．３×１０＾－４￣１．０×１０＾－３ｍｏｌ／Ｌ。将电极用于实际试样中的回收率测定时，获得了较好的结果。     

L—天冬门酰胺微生物电极的研制

以谷氨酸棒状杆菌作为生物催化剂，与基础氨气敏电极结合制成对Ｌ－天冬门酰胺响应的微生物电极，在３０℃时选择ＰＨ＝８．５的硼酸缓冲体系，测得电极的线性范围为７．１×１０＾－５－１．１×１０＾－２ｍｏｌ／Ｌ，斜率为５１．４ｍＶ／ｄｅｃ，检测下限为２．０×１０＾－５ｍｏｌ／Ｌ，响应时间为４－７ｍｉｎ寿命达３０ｄ以上。     

五羟色胺分子选择性电极研究

本应用自己合成的联萘２０－冠－６作为活性载体，进行了五羟色胺分子选择性电极研究。电极在１０＾－＾５－１０＾－＾２ｍｏｌ／Ｌ浓度范围内对五羟色胺具有稳定的线性响应，平均斜率为６３ｍＶ／ＰＣ，检测下限为２．７×１０＾－＾６ｍｏｌ／Ｌ。     

伏安型植物组织生物微电极的研究：混合不同植物组织碳糊微电极的研究

由于香蕉组织中含有的氧化酶能够生物催化氧化多巴胺，去甲肾上腺素，Ｌ－多巴等，大大地提高了植物组织电极的灵敏度；又由于茄子组织中所含有的氧化酶在催化氧化儿茶酚的同时，能有效地抑制抗坏血酸在电极上的反应，将上述两种植物组织混合制成电极，使其更适于神经递质的测定，线性范围：２．４×１０＾－６－－９．８×１０＾－４ｍｏｌ／Ｌ；检出下限３．２×１０＾－７ｍｏｌ／Ｌ。     

L—氨基酸氧化酶电极的制作及电极特性的研究

报道了一种新的Ｌ－氨基酸氧化酶电极，这种酶电极系由氨气敏电极和以氨基化玻璃布为载体的酶膜所组成；研究了固定化条件对酶膜活性的影响以及底物浓度、温度和ｐＨ对电极响应特性的影响。该电极在６．０×１０＾－５～４．０×１０＾－３ｍｏｌ／Ｌ的底物浓度范围内呈良好的线性关系，检测下限为５．０×１０＾－５ｍｏｌ／Ｌ。在最宜条件下，酶电极具有良好的稳定性。     

聚邻苯二胺修饰电极抗坏血酸氧化酶生物传感器的研究

本文报道了聚邻苯二胺／抗坏血酸氧化酶生物传感器，用这种传感器测定人体血清中的抗坏血酸，线性范围在１．０×１０＾－４～２．５×１０＾－７ｍｏｌ／Ｌ之间，响应时间为７ｓ，检测限为１．０×１０＾－８ｍｏｌ／Ｌ。该传感器具有选择性好、灵敏度高和响应时间短等特点。     

聚碱性品红修饰电极的制备及应用

研究了碱性品红在玻碳电极上聚合的最佳实验条件及其聚合机理，发现该修饰电极的多巴胺具有良好的催化作用，能大大提高多巴胺在的玻碳电极上的响应，在ｐＨ＝７．０的磷酸盐缓冲溶液中，用修饰电极测定巴胺的线性范围为２×１０＾－７～１×１０＾－５ｍｏｌ／Ｌ，检测限为１×１０＾－７ｍｏｌ／Ｌ，并且具有稳定性好，响应快，选择性等特点。     

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.     

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.     

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.