高效液相色谱法测定饲料中的喹乙醇

报道饲料中喹乙醇的高效液相色谱分析方法。以乙酰苯胺为内标,样品用二甲替甲酰胺（ＤＭＦ）提取,在Ｃ８柱上进行色谱分析,紫外检测波长２６０ｎｍ,流动相为甲醇－水（２０８０,Ｖ／Ｖ）,喹乙醇的回收率为９８．５８％～１０１．６３％,相对标准偏差为２．６７％～４．２５％。     

5-磺酸钠间苯二甲酸二甲酯的高效液相色谱法分析

提出了用离子对反相高效液相色谱分析５－磺酸钠间苯二甲酸二甲酯的方法,色谱柱为ＨｙｐｅｒｓｉｌＢＤＳＣ１８,５μｍ,２５０ｍｍ×４．６ｍｍ,流动相为Ｖ（甲醇）∶Ｖ（水）＝６０∶４０（甲醇中含四丁基磷酸二氢铵１０ｍｍｏｌ／Ｌ）,柱温为３０℃,流速为０．８ｍＬ／ｍｉｎ,进样体积为２０μＬ,检测波长为２２０ｎｍ。用外标法进行了定量,相对标准偏差和回收率分别为０．２６％和９８．１％～９９．６％。     

反相高效液相色谱法测定新药阿司匹林铜

提出测定阿司匹林铜新药的反相高效液相色谱分析方法,采用国产ＹＷＱ Ｃ１８柱,在２５℃下,甲醇：水（含０．０８％正磷酸）：丙酮＝１１．４：８．６：１．１为流动相,苯甲酸为内标,药用标准阿司匹林和水杨酸为对照品,在ＵＶ－２３５ｎｍ下检测阿司匹林铜和杂质水杨酸铜的含量;阿司匹林铜,水杨酸铜的检出限分别为０．８７ｍｇ／Ｌ,２．４６ｍｇ／Ｌ;阿司匹林铜的回收率为９９．０％－１００．５０％;水杨酸铜的回收率为     

反相高效液相色谱法测定杜仲中的松脂醇二葡萄糖甙

建立一种测定杜仲中松脂醇二葡萄糖甙的反相高效液相色谱法。杜仲粉末的甲醇提取液经大孔树脂柱处理后,在ＹＷＧ－Ｃ１８柱上进行ＨＰＬＣ分析。流动相为２８％（Ｖ／Ｖ）的甲醇水溶液;流速１．０ｍＬ／ｍｉｎ;紫外检测波长２３２ｎｍ。方法平均回收率为９９．２２％（ｎ＝３）,变异系数０．５０％～０．７４％（ｎ＝５）。进样量在０．０６８μｇ～０．６８μｇ范围内线性关系良好,ｒ＝０．９９９９。所建立的方法可作为评定杜仲及杜仲制品降压效果的一种简便、快速和准确的测定方法。     

高效液相色谱法测定非诺贝特含量

以甲醇－水（９５：５,Ｖ／Ｖ）为流动相,用ＯＤＳ柱以高效液相色谱法测定非诺贝特含量。紫外检测波长为２８６ｎｍ。非诺贝特在浓度为０．０４－０．２０ｇ／Ｌ间线线性关系良好。重复进样ＲＳＤ＝０．１４％,最低检出浓度为０．１０ｍｇ／Ｌ,平均回收率为９９．６６％。     

HPLC法测定氯霉素氢化可的松滴耳液中两组分的含量

采用反相高效液相色谱法,以醋酸泼尼松为内标,ＵＶ检测波长为２４４ｎｍ,以ＹＷＧ－Ｃ１８为固定相,以甲醇－水（６０∶４０）为流动相,同时测定了氯霉素氢化可的松滴耳液中氯霉素和氢化可的松的含量,并进行了线性范围和回收率测定,平均回收率（ｎ＝６）和相对标准偏差分别为：９９．９１％和０．８６％（氯霉素）,９９．５８％和１．３４％（氢化可的松）。     

鱼肉中微囊藻毒素的高效液相色谱法分析

应用反相高效液相色谱法分析了鱼肉中藻毒素的含量。用BDS C18色谱柱,以水（含1％三氟乙酸）：甲醇＝30：70（V／V）溶液为流动相,238nm紫外检测。鱼肉样品用甲醇－水和丙酮混合溶剂提取,经正已烷萃取后,将有机相弃去,水相用固相萃取柱净化后进行高效液相色谱分析。该法检测限为10ng/g,峰面积标准曲线在50－250ng范围内有良好线性关系,平均回收率为85．1％－88．2％。     

用反相高效液相色谱法分离和测定丁烯二酸的顺反异构体

建立了分离和测定丁烯二酸的２个异构体－顺丁烯二酸和反丁烯二酸的反相高效液相色谱法。以Ｓｈｉｍ－ｐａｃｋ ＣＬＣ－ＯＤＳ柱为分析柱,以甲醇－水（体积比５：２）,用磷酸调至ｐＨ３．０）为流动相,流速０．７ｍＬ／ｍｉｎ,检测波长为２２０ｎｍ,外标法定量。顺、反丁烯二酸的检出限分别为０．１０和０．０７５ｍｇ／Ｌ（Ｓ／Ｎ＝２）;相对标准偏差分别为０．４７％和０．５４％（ｎ＝３）。二者的线性范围均为１０～６０     

决明子药材中大黄酚量的反相HPLC法测定

以甲醇－水（体积比８０：２０）为流动相,采用反相高效液相色谱法测定了生,炔决明子中大黄酚的量,平均回收率９８．１％,ＲＳＤ为２．３％（ｎ＝５）,方法简便,灵敏,重现性好。     

反相高效液相色谱法测定雷公藤提取物中雷公藤甲素含量

应用反相高效液相色谱法检测了雷公藤提取物中雷公藤甲素的含量。样品经洗脱提取后,以Ｃ１８化学键合硅胶为固定相,乙腈－水（４０∶６０,Ｖ／Ｖ）为流动相,用２１０ｎｍ波长定量检测。测定结果表明,雷公藤甲素浓度在０．２５～４．００ｍｇ／Ｌ范围内线性良好,最低进样检测浓度为０．１ｍｇ／Ｌ。批内（ｎ＝５）及批间（ｎ＝５）测定相对标准偏差分别为１．９％～６．５％和２．７％～７．８％,回收率为８９．８％～９２．０％。     

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%.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.