脂肪胺荧光衍生物的高效液相色谱分离及质谱鉴定

采用新型荧光衍生试剂2-(9-吖啶酮)-乙酸(AAA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性.衍生物荧光激发和发射波长为λex=404nm,λem=440nm.30℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应20min后获得稳定的荧光产物.在HypersilBDSC18(4.6mm×100mm,5μm)色谱柱上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离.采用大气压化学电离源(APCISource)正离子模式进行在线柱后质谱定性,实现了各种脂肪胺衍生物的快速、准确测定.该方法具有良好的重现性,多数脂肪胺的线性回归系数大于0.9996,检测限为12.09~25.52fmol.     

2-(11H-苯[a]咔唑)-乙酸在脂肪胺的高效液相色谱分离及质谱鉴定中的应用

采用新型荧光衍生试剂2-(11H-苯[a]咔唑)-乙酸(BCA)进行柱前衍生并经荧光检测对脂肪胺进行高效液相色谱(HPLC)分离和质谱定性.衍生物荧光激发和发射波长为λex=285 nm,λem=384 nm.60 ℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)作催化剂, 衍生反应15 min后获得稳定的荧光产物.在Hypersil BDS C18 (4.0 mm×200 mm, 10 μm) 色谱柱上, 采用梯度洗脱对12种脂肪胺衍生物进行了优化分离.采用大气压化学电离源(APCI Source)正离子模式进行质谱定性, 实现了各种脂肪胺衍生物的快速、准确测定.脂肪胺的线性回归系数不小于0.999 8 , 检出限(S/N=3)为5.73 ～31.3 fmol.     

新型荧光衍生试剂用于脂肪胺的反相高效液相色谱-荧光检测分析

利用新型荧光试剂4-(1H-菲并[9,10-d]咪唑-2-)苯甲酸(PIBA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性。激发和发射波长分别为ex=261nm,em=443nm。80℃下在吡啶溶剂中用N-乙基-N’-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应10min后获得稳定的荧光产物。在EclipseXDB-C8色谱柱(4.6150mm,5mm)上,梯度洗脱对12种游离脂肪胺衍生物进行了优化分离。采用大气压化学电离源(APCI)正离子模式,实现了各种脂肪胺衍生物的测定。多数脂肪胺的线性回归系数大于0.9999,检测限为10.5～53.4fmol。     

氮杂环荧光试剂2-(11H-苯[a]咔唑)乙基氯甲酸酯对胺类化合物标记及质谱鉴定

含氮类荧光试剂2-(11H-苯[a]咔唑)乙基氯甲酸酯(BCEC-Cl)经柱前衍生处理后,采用荧光检测及柱后在线质谱鉴定对食品中胺类化合物进行了测定。标记反应在pH9的硼酸缓冲液中进行,3min后获得稳定的荧光产物。衍生物于λex=279nm激发条件下产生强烈荧光,其发射波长在λem=380nm处。产物的分离在EclipseXDB-C8色谱柱(150mm×4.6mm,5μm)上进行,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离。采用大气压化学电离源(APCISource)正离子模式进行在线的柱后质谱鉴定,实现了多种脂肪胺衍生物的快速、准确测定。建立的方法具有良好的重现性,回归系数大于0.9996,检出限为1.8~14fmol。     

氮杂多环光致发光分子用于食品中脂肪胺的分析及质谱鉴定

对含氮类光致发光分子2-（11H-苯[a]咔唑）-异丙基氯甲酸酯进行柱前衍生处理,并经荧光检测对脂肪胺进行高效液相色谱（HPLC）分离和质谱定性。衍生物于λex=279nm产生强烈荧光,发射波长为λex=380nm。40℃下在pH9．0的硼酸缓冲液中,衍生反应3min后获得稳定的荧光产物。在Eclipse XDB-C8色谱柱（4．6mm×150mm,5μm）上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离。采用大气压化学电离源（APCI Source）正离子模式进行质谱定性,实现了各种脂肪胺衍生物的快速、准确测定。该方法具有良好的重复性,多数脂肪胺的线性回归系数大于0．9994,检出限在2．73～23．16fmol水平。     

新型荧光试剂用于土壤中脂肪胺的高效液相色谱-质谱测定

利用新型荧光试剂2-(2-(10-蒽基)-苯并咪唑)-乙酸(ABIA)为柱前衍生化试剂,在Akasil-C18色谱柱上,通过梯度洗脱对12种游离脂肪胺进行了分离和在线质谱定性。以乙腈为溶剂,N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)为缩合剂,在50℃条件下衍生反应20 min后获得稳定的荧光产物。激发波长和发射波长分别为260 nm和430 nm,采用大气压化学电离源(APCI)的正离子模式,实现了土壤中脂肪胺的定性及其含量的测定。脂肪胺的线性相关系数大于0.9990,检出限为11.72~25.63 fmol。     

脂肪胺的高效液相色谱分离及质谱鉴定

 采用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙酸(BCAA)为柱前衍生化试剂,在Hypersil BDS-C18色谱柱上,通过梯度洗脱对12种游离脂肪胺进行了分离和在线质谱定性。以乙腈为溶剂,1-乙基-3-(3-二甲氨基丙基)环己碳二亚胺(EDAC)为缩合剂,在50 ℃条件下衍生反应15 min后获得稳定的荧光产物。激发波长和发射波长分别为333 nm和390 nm。采用大气压化学电离源(APCI)的正离子模式,实现了土壤和污水中脂肪胺的定性及其含量的测定。脂肪胺的线性相关系数大于0.9993,检测限为12~28 fmol。     

污水中脂肪胺荧光衍生物的高效液相色谱分离及质谱鉴定

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-异丙基氯甲酸酯(BCIC)作为柱前衍生化试剂,在乙腈中,以硼酸钠缓冲液(pH 9)为催化剂,40 ℃下衍生反应10 min后获得稳定的荧光产物.在Eclipse XDB-C8色谱柱上,通过梯度洗脱对12种游离脂肪胺进行了分离和在线质谱定性.激发和发射波长分别为λex=333 nm,λem=390 nm.采用大气压化学电离源(APCI)正离子模式,实现了污水中脂肪胺的定性及相应含量测定.脂肪胺的线性回归系数大于0.9996,检出限在10.57～37.83 fmol.     

2-[2-(7H-二苯并[a,g]咔唑)-乙氧基]-乙基氯甲酸酯对脂肪胺类化合物的荧光标记及质谱鉴定

利用新型荧光标记试剂2-[2-(7H-二苯并[a,g]咔唑-乙氧基)-乙基氯甲酸酯作为柱前衍生化试剂, 在Eclipse XDB-C8反相色谱柱上,采用梯度洗脱,实现了12种脂肪胺类化合物完全基线分离.检测最佳激发和发射波长分别为300和400 nm.通过荧光检测及离子阱大气压化学电离源(APCI Source)正离子模式实现了在线的柱后质谱鉴定.对土壤中脂肪胺类化合物的测定快速、准确,具有良好的重现性.荧光定量检测的回归系数大于0.9991; 检出限为10.1～0.3 fmol.     

荧光衍生-高效液相色谱分离及质谱鉴定芳香胺

含氮杂环光致发光分子经柱前衍生化,采用荧光检测及柱后在线质谱鉴定对废水中胺类化合物进行了测定.衍生物荧光激发和发射波长分别为λex=275 nm,λem=380 nm.在pH 8.0的硼酸钠缓冲液中,于40 ℃下衍生反应40 min后获得稳定的荧光产物.在Hypersil BDS C18柱上,采用梯度洗脱对5种芳香胺衍生物进行了优化分离.采用大气压化学电离源(APCI Source)正离子模式进行在线的柱后质谱定性,实现了5种芳香胺衍生物的快速、准确测定.方法具有良好的重现性,线性回归系数大于0.9998,检出限在71～81 fmol水平.     

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.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

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.     

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.