高效液相色谱-电喷雾串联质谱法测定蔬菜中虫酰肼和甲氧虫酰肼残留

建立了蔬菜中虫酰肼和甲氧虫酰肼的高效液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)检测方法。样品经碱性乙腈提取,固相萃取净化,反相高效液相色谱柱分离后进行质谱分析。在选择反应监测模式(SRM)下进行特征母-子离子对信号采集。分别以碎片离子m/z297和m/z149进行外标法定量。虫酰肼和甲氧虫酰肼残留的检出限(S/N=3)为1.0μg/kg,加标回收测得定量限为4.0μg/kg;在5.0～200μg/L时峰强度与质量浓度的线性关系良好(r2>0.996)。在4.0、10.0和20.0μg/kg3个添加水平,通过基质曲线校正后,虫酰肼和甲氧虫酰肼的平均回收率范围为90%～110%和70%～80%;相对标准偏差小于8%。结果表明,该法简单、灵敏,适用于蔬菜中虫酰肼和甲氧虫酰肼残留的分析确证。     

花生中丁酰肼残留测定的两种衍生方法比较

对气相色谱-质谱联用法(GC-MS)测定花生中残留丁酰肼含量时,衍生化所用的两种衍生试剂,水杨醛和2-硝基苯甲醛,在衍生反应的介质及条件、检测响应值、标准曲线的线性范围以及测定下限和回收率等方面作了详细比较.试验结果表明:两种试剂均适合作为衍生试剂,但从衍生反应操作简便以及较高的灵敏度和较好的回收率等方面考虑,用水杨醛作衍生试剂效果更好,而且在衍生化过程中用离心法除去反应而残留的水杨醛更保证了检测的精密度.应用这一方法所测得丁酰肼的测定下限(10S/N)为0.005 mg·kg-1,用标准加入法测得的回收率在98.0%～99.4%之间,测定值的相对标准偏差(n=6)在1.5%～3.6%之间.     

反相流动注射分光光度法测定海水中的Cr(Ⅵ)

建立了以二苯碳酰二肼为显色剂,丙酮溶液为载液,反相流动注射分光光度法测定海水中痕量Cr(Ⅵ)的方法。考察了显色剂中二苯碳酰二肼浓度、显色剂酸度、反应圈、流速等因素的影响。结果表明本法测定Cr(Ⅵ)线性范围为0~100μg/L,检出限为0.36μg/L,对海水中的Cr(Ⅵ)进行分析,回收率在95.0%~102.0%。     

新型蒈酸基双酰肼化合物的合成及其生物活性

先将3-蒈烯分子中的碳碳双键氧化开环制得蒈酮酸，再将羰基还原成亚甲基得到蒈酸，酰氯化后与系列酰肼发生N-酰化反应合成了14个新型蒈酸基双酰肼化合物(5a～5n)，其结构经UV-Vis、¹H NMR、¹³C NMR、 FT-IR和MS(ESI)表征，并测试了目标化合物的抑菌和除草活性。结果显示：在用药量为50 μg·mL^-1时，目标化合物对花生褐斑病菌、小麦赤霉病菌、黄瓜枯萎病菌、苹果轮纹病菌、番茄早疫病菌、玉米小斑病菌、西瓜炭疽病菌以及水稻纹枯病菌等8种植物病原菌具有一定的抑制活性，其中化合物蒈酸基α-噻吩甲酰肼5f（R=α-thiophene）对苹果轮纹病菌的抑制率达85.0%，优于阳性对照百菌清。在用药量为100 μg·mL^-1时，化合物蒈酸基3′,4′-二甲氧基苯甲酰肼5j(R=3′,4′-OMe-Ph)、蒈酸基-m-甲氧基苯甲酰肼5d(R=m-OMe-Ph)、蒈酸基-m-甲基苯甲酰肼5b(R=m-Me-Ph)和蒈酸基苯甲酰肼5a(R=Ph)对油菜胚根生长的抑制率分别为88.5%、 86.1%、 85.1%和82.6%（均为A级活性水平），优于阳性对照丙炔氟草胺。     

亲水作用液相色谱-串联质谱测定烟叶中马来酰肼及其糖苷

建立了一种基于亲水作用液相色谱-串联质谱的烟叶中马来酰肼及其糖苷的定量分析方法。方法采用乙腈-甲基叔丁基醚-水（7：10：13,体积比）超声波辅助提取烟叶中的马来酰肼及其糖苷,提取液经离心分相和溶剂置换后进行亲水作用液相色谱-串联质谱分析。马来酰肼及马来酰肼-O-β-D-葡萄糖苷的基质添加标准曲线的线性范围为5~150 mg/kg,相关系数（r²）为0.9971及0.9972,检出限分别为0.5 mg/kg和0.3 mg/kg,定量限分别为1.0 mg/kg和0.8 mg/kg。马来酰肼及马来酰肼-O-β-D-葡萄糖苷在10、40、80 mg/kg 3个加标水平下的回收率为83.1%~112.3%,在40 mg/kg加标水平下的日内重复性分别为2.7%和3.8%,日间重复性分别为8.3%和7.1%。应用该方法分析喷洒马来酰肼28天后烟叶中马来酰肼的分布情况,发现马来酰肼含量减少了80.8%,其中仅有7.6%转化成了马来酰肼糖苷,其他马来酰肼的去向有待进一步研究。     

刺激响应性共聚物修饰金纳米棒的制备及其抗肿瘤性能

以1-叔丁氧基羰基-2-丙烯酰肼(Boc-AH)、N-(3,4-二羟基苯乙基)丙烯酰胺(DA)和聚乙二醇甲醚丙烯酸酯(mPEGA)为单体,利用可逆加成-断裂链转移聚合法制备了嵌段共聚物聚丙烯酰肼-聚N-(3,4-二羟基苯乙基)丙烯酰胺-聚单甲氧基聚乙二醇丙烯酸酯(PAH-b-PAD-b-PmPEGA,缩写为HDP),该...     

N-叔丁基-N'-氟代苯甲酰基-取代吡啶甲酰肼衍生物的合成与杀虫活性研究

为改进双酰肼类杀虫剂的性能,将氟代苯基和吡啶环同时引入双酰肼的基本结构中,设计合成了20个新型的N-叔丁基-N'-氟代苯甲酰基-取代吡啶甲酰肼衍生物,经~1H NMR、~(13)C NMR、IR和HRMS确证了分子结构.生物活性测试表明,在浓度为500 mg/L时,大部分化合物对粘虫(Mythimna separata)的致死率都达到80%以上.其中N-叔丁基-N'-(2,6-二氟苯甲酰基)-2-氯烟酰肼(6bb)和N-叔丁基-N'-(2,6-二氟苯甲酰基)-2,5-二氯烟酰肼(6gb)在浓度为10 mg/L时对粘虫的致死率分别为100%和80%.化合物6bb对东方粘虫的半致死浓度(LC_(50)值)为8.77 mg/L,对东方粘虫的毒力约为虫酰肼的0.51倍,对小菜蛾(Plutella xylostella)的毒力为虫酰肼的1.5倍.     

芳香胺和酚溴化的新工艺

研究了在室温下,N-溴丁二酰亚胺对芳香胺和酚的溴化工艺,在CHCl3、EtOH或EtOH/CHCl3溶剂中,用等摩尔的N-溴丁二酰亚胺可将某些芳香胺和酚(考察了5种反应底物)选择性地一溴化,产率92%~98%,N-溴丁二酰亚胺和反应底物摩尔比为2∶1;某些芳香胺和酚被专一地二溴化(考察了5种反应底物),产率90%~97%。 反应无须催化剂,投料后室温搅拌,反应条件温和,产品只需过滤洗涤即可纯化,操作简便。     

非甾体抗炎药对映体在冠醚手性固定相上的拆分

利用高效液相色谱法,采用从(18-冠-6)-2,3,11,12-四羧((18-crown-6)-2,3,11,12-tetracarboxylic acid,18-C-6-TA)衍生的冠醚类型手性固定相(CSPs),对非甾体抗炎药酰肼衍生物进行手性分离研究.为了手性酸类非甾体抗炎药在冠醚手性固定相上进行手性拆分,采用与肼合成方法导入氨基基团,合成了其酰肼衍生物.色谱条件为:流动相:80%甲醇/水(V/V)含10 mmol/L H2SO4;流速:1.0 mL/min;紫外检测波长:210 nm.结果表明,除酮洛芬之外,其它非甾体抗炎药的酰肼衍生物拆分效果较好(α=1.14～1.26,Rs=0.88～1.43).而且非甾体抗炎药酰肼衍生物在(+)18-C-6-TA衍生的CSP 1和(-)18-C-6-TA衍生的CSP 2上的洗脱顺序得到了相反结果.     

马铃薯中马来酰肼的高效液相色谱法测定

建立了马铃薯中马来酰肼的高效液相色谱(HPLC)检测方法.马铃薯样品经酸化甲醇提取,高速离心沉淀分离后,以甲醇-去离子水(体积比1:9,pH 2.7)为流动相,采用ZORBAX SB C18柱(250 mm×4.6 mm×5 μm)分离,在UV 205 nm检测,外标法定量.结果表明,马来酰肼提取液的线性范围为0.2 ～16.0 mg/L,回收率为82% ～94%,RSD均小于2%,马铃薯中马来酰肼的定量下限为1.0 mg/kg.     

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.