液相色谱-串联质谱法鉴定大鼠血浆中的东莨菪碱及其代谢物

建立了鉴别东莨菪碱及其代谢物的液相色谱-电喷雾离子阱串联质谱(LC-MSn)联用方法。取单剂量灌胃50 mg/kg东莨菪碱的大鼠血样,甲醇沉淀蛋白,采用LC-MS及LC-MSn等方法分析血样。和空白血样及东莨菪碱相比较,根据血样中代谢物分子量的变化(ΔM)及其多级质谱数据,鉴定并阐述其结构。结果在服药后的大鼠血样中发现7种代谢物,分别为莨菪品、N-去甲基莨菪品、脱水东莨菪碱,N-去甲基脱水东莨菪碱、N-去甲基东莨菪碱、氧化东莨菪碱以及托品酸等。该方法灵敏,快速,简便,适合于药物及其代谢物的快速鉴定。     

液相色谱-串联质谱法分析樟柳碱大鼠肝匀浆代谢产物

运用液相色谱-电喷雾离子阱串联质谱(LC-MSn)联用技术研究了樟柳碱大鼠肝匀浆中的代谢物。采用离体实验的代谢研究方法,将樟柳碱与大鼠肝匀浆在富氧条件下温孵,代谢物以乙酸乙酯萃取,以ReliA-sil C18(5μm,2 mm×150 mm)为分离柱,甲醇/0.01%三乙胺溶液(用甲酸调节pH 3.5)(60∶40,V/V)为流动相,采用LC-MS及LC-MSn等方法进行分析。和原药相比较,根据温孵液中分析物分子量的变化(ΔM)及其多级质谱数据,在樟柳碱的大鼠肝匀浆培养液中鉴定出了2种代谢物,即脱水去甲基樟柳碱和N-氧化樟柳碱。实验结果表明,该液相色谱-串联质谱方法适合于药物代谢物的快速分析。     

液相色谱-电喷雾离子阱质谱分析3种兴奋剂类毒品及其代谢物

建立了3种常见兴奋剂类毒品3,4-亚甲二氧甲基苯丙胺(MDMA)、甲基苯丙胺(MA)、可卡因及其代谢物同时分离与鉴定的液相色谱-电喷雾离子阱质谱(LC-ESI-ITMS)方法。通过体外代谢方法得到大鼠肝微粒体S9组分中MDMA、MA、可卡因及代谢产物混合体系后,利用LC-ESI-ITMS联用技术对各代谢物进行分析,得到各代谢物的[M+H]+分子量信息,进一步结合多级串联质谱(LC-MSn)分析结果获得结构信息,对代谢物进行鉴定,从而快速推测代谢物结构,得到MDMA、MA、可卡因的主要代谢产物。所建立的方法用于3种常见兴奋剂类毒品及其代谢物的分析,具有快速、高效、灵敏、选择性好等特点。     

大鼠尿液中异丙嗪及其主要代谢物的GC-MS分析

采用气相色谱-质谱(GC-MS)分析了大鼠尿液中的异丙嗪及其代谢产物。尿液经β-葡萄糖醛酸酶酶解,Oasis(HLB 3 mL固相萃取柱提取后,以Restek R tx-5MS(30 m×0.25 mm×0.25μm)石英毛细管色谱柱为分析柱,经GC-MS分离检测。根据质谱图对代谢物的结构进行鉴定。结果表明:在大鼠尿液中检出了吩噻嗪、去甲基异丙嗪、异丙嗪亚砜、2-羟基去甲基异丙嗪、二羟基异丙嗪、顺-N-(1-丙烯基)吩噻嗪、反-N-(1-丙烯基)吩噻嗪、顺-N-(1-丙烯基)吩噻嗪砜、反-N-(1-丙烯基)吩噻嗪砜、顺-N-(1-丙烯基)吩噻嗪亚砜及反-N-(1-丙烯基)吩噻嗪亚砜11种代谢物。对异丙嗪在大鼠体内的氧化、还原等主要代谢途径进行了讨论。     

超高压液相色谱-飞行时间质谱法对比分析沙丁胺醇在猪尿液和血浆中的代谢产物

采用高分辨质谱及代谢物鉴定软件,系统分析了猪尿液和血浆中沙丁胺醇代谢产物。样品用乙腈沉淀蛋白,经离心过滤后,采用Agilent Plus C18色谱柱,以乙腈和醋酸溶液(含0.2%醋酸)作为流动相进行梯度洗脱,采用高分辨质谱(UHPLC-QTOF MS)±离子模式进行检测,利用软件Agilent MassHunter MetaboliteID与人工相结合分析检测数据。结果表明,经灌胃给药后猪尿液中鉴定出沙丁胺醇原形药和葡糖醛酸化、苯环羟基化、N-氧化、苯环甲氧基化、羟基化脱水共5个代谢产物,其中2个代谢物未见文献报道;而血浆中仅检测原型药物和2个代谢物,包括沙丁胺醇的葡糖醛酸化和N-氧化产物。     

液相色谱-电喷雾离子阱质谱结合“Nin1”模式用于高通量分析药物及其代谢物

本文建立了一种基于液相色谱-电喷雾离子阱质谱(LC-ESI-ITMS)技术和"Nin1"模式的药物及其代谢物快速高通量分离与鉴定方法.该方法首先利用体外代谢方法得到肝微粒体中药物与各自代谢产物混合体系,然后采用"Nin1"模式对该混合体系进行处理,并利用LC-ESI-ITMS联用技术对各待测药物及其代谢物进行分析,得到药物和代谢物的分子量信息,进一步结合多级串联质谱(LC-MSn)分析结果获得结构信息,对代谢物进行鉴定,从而快速的推测代谢物结构,进而得到药物的生物转化规律.本方法用于6种药物及其4种代谢物的分析,实验结果表明:该方法具有快速、高效、灵敏,选择性好等特点.     

柱前衍生化结合LC-MS~n分析人尿中茶碱及其代谢物

采用固相萃取结合化学衍生化的样品柱前预处理方法,利用液相色谱-电喷雾/多级质谱联用技术(LC-ESI/MSn),对人经口服给药后尿液中的茶碱及其代谢产物进行分析,探讨了茶碱、代谢物及相关衍生物的质谱裂解行为,推测茶碱在人体内的代谢途径。尿样经Bond Elute C18小柱固相萃取,收集甲醇洗脱部分在50℃下氮气吹干,以N,N-二甲氨基氯乙烷为衍生试剂进行衍生化。以Shimpack C18为色谱柱、甲醇-水-甲酸(体积比20∶80∶1)为流动相,在正离子模式下对尿样中茶碱、代谢物及其衍生化产物进行LC-ESI/MSn分析。采用上述方法,共分析鉴定了人尿中的茶碱和4种代谢物(1-甲基尿酸、1,3-二甲基尿酸、1-甲基-N-乙酰化物、3-甲基黄嘌呤),其中1种代谢物未见文献报道。在正离子模式下,茶碱及代谢物的二级质谱大多丢失18 u,28 u或57 u片段生成一系列碎片离子,而衍生化产物的二级质谱均有规律地丢失45 u片段生成一系列碎片离子。通过与未经衍生化的尿样比较发现,衍生化可明显增强茶碱、1-甲基尿酸和3-甲基黄嘌呤的质谱检测灵敏度。本研究补充了茶碱在人体内的代谢轮廓,可为灵敏检测生物样本中茶碱、代谢物及其结构类似物提供借鉴。     

甲基原薯蓣皂苷静脉注射给予大鼠后体内代谢物的LC-MS~n分析

采用液相色谱-多级离子阱质谱法(LC-MSn)法,检测大鼠生物样本中的甲基原薯蓣皂苷(MPD)及其代谢产物,以推测MPD在大鼠体内的代谢途径。对大鼠静脉注射给予40 mg/kg的MPD,并收集尿液、血浆、胆汁和粪便等样本,经固相萃取(SPE)净化提取后,采用Phenomenex Gemini C18色谱柱,以甲醇(B)-水(A)为流动相进行梯度洗脱,流速1.0 mL/min。采用正负离子检测。在生物样本中共检测到14个代谢产物。通过与对照品的色谱行为和多级质谱特征相比对,鉴定了其中6个代谢产物,分别为Protodioscin(M3),26-O-β-D-Glucopyrannosyl-(25R)-furan-5-ene-3β,22α,26-trihydroxy-3-O-α-L-rhamnopyranosyl-(1→2 or 4)-β-D–glucopyranoside(M5),MPD(M0),Pseudoprotodioscin(M7),26-O-β-D-Glucopyrannosyl(25R)-furan-5-ene-3β,26-dihydroxy-22-methoxy-3-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranoside(M9),26-O-β-D-Glucopyrannosyl(25R)-furan-5-ene-3β,26-dihydroxy-22-methoxy-3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside(M10)和Dioscin(M11)。根据已有对照品的质谱裂解规律,用LC-MSn法推测了另外5个代谢物。其中Protodioscin(PD)和Dioscin是两个主要的代谢产物,其对应的生成途径是MPD在大鼠体内的主要代谢途径。代谢反应总体以一相代谢为主,主要是水解脱糖,同时检出2个二相代谢产物;代谢物结构变化主要发生在糖上,母核均无明显变化。     

大鼠血液中溴莫普林的代谢产物核磁共振氢谱和质谱研究

用核磁共振氢谱和质谱法研究大鼠血浆中溴莫普林（BDP)及其代谢物。首先用固相萃取法将血液中内源性物质除去,然后经核磁共振氢谱和质谱检测大鼠血液中BDP及其代谢物。大鼠服用溴莫普林后20h时血浆中检测到两个代谢产物：脱甲基－溴莫普林葡萄糖醛酸和溴莫普林硫酸。结果证明核磁共振氢谱和质谱法可以快速、方便地用于血液中药及其代谢产物的含量与结构检测的研究。     

气相色谱-质谱/质谱法检测蔬菜中的毒死蜱及其代谢物

建立了蔬菜中毒死蜱及其代谢物3,5,6-三氯-2-羟基吡啶（3,5,6-trichloro-2-pyridinol,TCP)的气相色谱-质谱/质谱分析方法。蔬菜样品采用丙酮提取,浓缩后TCP用N-甲基-N-叔丁基二甲基硅基三氟乙酰胺(MTBSTFA)衍生,再经氟罗里硅土固相萃取柱净化。采用三重四极杆质谱电子轰击多反应监测(MRM)模式测定。采用内标法对毒死蜱定量,方法的检出限为1 μg/kg,加标回收率为75.57%～106.41%,相对标准偏差(RSD)为8.33%～17.58%。采用外标法对TCP定量,方法的检出限为0.5 μg/kg,加标回收率为69.11%～108.43%,RSD为5.20%～19.42%。在2～100 μg/L范围内,两种被测物的线性关系良好（r＞0.99）。该方法可用于蔬菜中毒死蜱及其代谢物的检测。     

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%.     

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.     

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.     

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.