含氟酰基胂叶德的合成及其裂解反应

作者曾报道三氟乙酰基亚甲基三苯基胂 和双(三氟乙酰基)亚甲基三苯基胂的合成, 发现这二种含氟胂叶立德非常 稳定, 难于和醛酮反应。通过对三氟乙酰基亚甲基三苯基胂晶体结构的测定。证实了其稳定性。本文将上述方法扩展, 用来合成多氟酰基胂叶立德和双(多氟酰基)胂叶立德。     

含氟酰基胂叶德的合成及其裂解反应

作者曾报道三氟乙酰基亚甲基三苯基胂 和双(三氟乙酰基)亚甲基三苯基胂的合成, 发现这二种含氟胂叶立德非常 稳定, 难于和醛酮反应。通过对三氟乙酰基亚甲基三苯基胂晶体结构的测定。证实了其稳定性。本文将上述方法扩展, 用来合成多氟酰基胂叶立德和双(多氟酰基)胂叶立德。     

第五、六族元素的有机化合物在有机合成中应用的研究 ⅩⅩⅩⅠ.应用稳定胂叶立德合成β-酮酸酯和β-二酮的一种简便方法

本文报道一种在温和条件下使稳定胂叶立德(1)砷—碳键断裂的方法,从而合成了β-酮酸酯和β-二酮类化合物,特别是相应的含氟化合物.该方法操作简便,产物容易分离提纯,得率较好.     

膦,胂叶立德与贫电子炔类化合物的反应以及多官能基含氟有机化合物的合成

本文综述了膦,胂叶立德与丙炔酸甲酯,2-全氟炔酸甲酯和2-全氟炔腈的反应,以及利用反应产物合成多官能基含氟有机化合物.     

第五 六族元素的有机化合物在有机合成中应用的研究XXXI. 应用稳定胂叶立德合成β-酮酸酯和β-二酮的一种简便方法

本文报道一种在温和条件下使稳定胂叶立德(1)砷-碳键断裂的方法,从而合成了β-酮酸酯和β-二酮类化合物,特别是相应的含氟化合物,该方法操作简便,产物容易分离提纯,得率较好。     

树脂分离-氢化物发生-原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂

建立了用阴离子交换树脂分离-氢化物发生原子荧光光谱法测定食品中无机砷、一甲基胂和二甲基胂的方法.分别从样品上样条件及二甲基胂、一甲基胂、 As(Ⅲ)和As(Ⅴ)分离条件进行了优化.研究了树脂处理程序对分离的影响,并探讨了共存离子对测定砷的干扰和消除的方法.对方法的适用范围做了研究.本方法具有操作简便、快速、灵敏度高等优点.检出限(以砷计)分别为: 无机砷0.34 μg/L,一甲基胂0.57 μg/L,二甲基胂0.46 μg/L.     

某些含有机胂二茂铁基胺衍生物的合成

锂化二甲氨甲基二茂铁与二本基氯化胂反应生成2-(二苯胂基)二甲氨甲基二茂铁及很少量的2,5-二(二苯胂基)二甲氨甲基二茂铁.在四甲基乙二胺(TMEDA)存在下,锂化的二甲氨甲基二茂铁与二苯基氯化胂反应则得到2,1'-二(二苯胂基)二甲氨甲基二茂铁.在不同条件下上述产物与过量碘甲烷作用生成多种不同的甲碘化物.     

膦、胂叶立德的化学与应用(ⅩⅣ)——膦、胂叶立德和丙炔酸甲酯的反应及部分加合物的水解

本文研究了甲氧羰基亚甲基三苯基胂(1b)、苯甲酰基亚甲基三苯基膦(1b)、胂、乙酰基亚甲基三苯基膦、胂、氰基亚甲基三苯基膦、胂、对-硝基苯基亚甲基三苯基膦(1i)和1-甲基-2-乙氧羰基亚甲基三苯基膦等9个膦、胂叶立德与丙炔酸甲酯(2)的反应以及1b和2反应的加合产物1,3-二甲氧羰基亚烯丙基三苯基胂(3b)及1i和2反应的加合产物1-甲氧羰基-3-对硝基苯基亚烯丙基三苯基膦(3i)在含水甲醇中的水解。     

碳-碳重键的新合成方法学研究

本研究工作包括下列8方面:(1)一种不同于Wittig反应的新的烯化方法,含氟β-酮基磷盐在有机合成中的应用。(2)"一锅"法的碳-碳双键形成反应。(3)一种新的叶立德阴离子的形成方法。(4)消去三苯基胂形成碳-碳双键的合成方法学。(5)立体选择性地控制合成(Z)或(E)-碳-碳双键化合物的新方法。(6)亲核试剂对全氟酰基膦酸酯进攻为基础的新合成方法学。(7)还原烯化反应的合成方法学。(8)含氟碳-碳叁键的合成方法学。     

使氧化三苯胂脱氧为三苯胂的新方法

本文报道用亚磷酸三苯酯或连二亚硫酸钠使氧化三苯胂还原为三苯胂的两个新方法.此法简便,反应条件温和,得率高,具有实用价值.用~(31)PNMR 研究了亚磷酸三苯酯和三苯膦对于氧化三苯胂、吡啶-N-氧化物、二甲亚砜的脱氧活性,并研究了钼配合物 Mo~(?)O_2[S_2CN(C_2H_5)_2]_2作为催化剂时对三苯膦和亚磷酸三苯酯脱氧活性的影响,讨论了上述反应的机理.     

二烷氧基膦酰乙酸酯的电子轰击正离子和化学电离负离子质谱研究

本文报道一系列二烷氧基膦酰乙酸酯的电子轰击(EI)正离子和甲烷化学电离负离子(NCI)质谱.在EI谱上出现特征的[M+H]^+离子,进一步发生氢重排,然后失去烯烃,再失水和脱CH2CO.而在NCI谱中则生成[M-H]^-离子(基峰),易失去烷基,再失烷氧基和CH2CO,或氢重排后脱烯烃.正、负离子的断裂机理不同,但数据可以互相补充,以利于类似未知物的结构分析.     

Reactivity of anomeric 1alpha- and 1beta-pentofuranosyl azide derivatives in ammonia chemical ionization

Electron impact (EI), fast atom bombardment (FAB) and ammonia chemical ionization [CI(NH3)] mass spectrometry were applied with the aim of differentiating between the anomeric 1alpha- and 1beta-azidopentofuranosyl derivatives. Calculated ammonium affinities [AA(M)] and proton affinities [PA(M)] show that beta-anomers have higher affinities for H+ and NH4+ ions than alpha-azides. Protonated molecules, obtained by CI(NH3) of azidofuranosyl derivatives, lose HN3 giving abundant furanosyl (S+) ions. Ammonia solvation of MH+ ions competes with the previous reaction producing the [SNHN2NH3]+ ion, a competitive product to the ammonium-attached [SN3NH4]+ ion. The fragmentation pathways of the stable and metastable [MNH4]+, MH+ ions, and several other important fragment ions, were determined using mass analyzed ion kinetic energy spectrometry (MIKES). The abundance of the [SN3NH4]+ and/or [SNHN2NH3]+ ions was found to correlate inversely with the exothermicity of ammonia solvation of the MH+ ion. The abundance of the fragment ions [SNHNH3]+, [SNH3]+ and SNH+ in some examples correlates with the exothermicity of the corresponding [MNH4]+ and MH+ parent ion formation. The fragment ions SNH3+ and SNHNH3+ can be formed, at least in part, in the ammonia solvation reaction of the S+ and SNH+ ions taking place within the high-pressure region of the CI ion source.     

Examination of the best pressure range for ion/molecule reactions of anthraquinones in an external source ion trap mass spectrometer.

This study outlines some observations of the pressure effect for gas phase ion-molecule reactions of anthraquinone derivatives with dimethyl ether in an external source ion trap mass spectrometer. At the reagent pressure of 7.998 x 10(-2) Pa, formation of the protonated ions, [M + 13]+, [M + 15]+, and [M + 45]+ ions, of anthraquinones can be observed. However, at the pressure of 1.066 x 10(-2) Pa, formation of molecular ions and many fragment ions of the M+. or [M + H]+ ions have been observed. Since the pressure effect is notable within a small range of pressures for many compounds, it is important to draw attention to the use of the ion trap with an external source where other factors such as ion source residence time may play a role. This can also provide some information for better and more careful controls of the reagent pressure in order to obtain fair CI spectra in an external source ion trap mass spectrometer.     

Determination of the fatty acyl profiles of phosphatidylethanolamines by tandem mass spectrometry of sodium adducts

Phosphatidylethanolamines (PEs) are one of the major constituents of cellular membranes, and, along with other phospholipid classes, have an essential role in the physiology of cells. Profiling of phospholipids in biological samples is currently done using mass spectrometry (MS). In this work we describe the MS fragmentation of sodium adducts of 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidylethanolamine (POPE) and 2-linoleoyl-1-palmitoyl-sn-glycero-3-phosphatidylethanolamine (PLPE). This study was performed by electrospray ionization tandem mass spectrometry (ESI-MS/MS) using three different instruments and also by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). All MS/MS spectra show product ions related to the polar head fragmentation and product ions related to the loss of acyl chains. In ESI-MS/MS spectra, the product ions [M+Na-R1COOH-43]+ and [M+Na-R2COOH-43]+ show different relative abundance, as well as [M+Na-R1COOH]+ and [M+Na-R2COOH]+ product ions, allowing identification of both fatty acyl residues of PEs, and their specific location. MALDI-MS/MS shows the same product ions reported before and other ions generated by charge-remote fragmentation of the C3-C4 bond (gamma-cleavage) of fatty acyl residues combined with loss of 163 Da. These fragment ions, [M+Na-(R2-C2H3)-163]+ and [M+Na-(R1-C2H3)-163]+, show different relative abundances, and the product ion formed by the gamma-cleavage of sn-2 is the most abundant. Overall, differences noted that are important for identification and location of fatty acyl residues in the glycerol backbone are: relative abundance between the product ions [M+Na-R1COOH-43]+ > [M+Na-R2COOH-43]+ in ESI-MS/MS spectra; and relative abundance between the product ions [M+Na-(R2-C2H3)-163]+ > [M+Na-(R1-C2H3)-163]+ in MALDI-MS/MS spectra.     

Liquid ionization mass spectrometry of some triorganotin carboxylates.

and ESI, in which [M + H]+ were not observed or the spectra were complicated. The liquid ionization mass spectra of triorganotin carboxylates varied with solvents and sample concentrations. For instance, the fragment ions [M + (C4H9)3Sn]+ of dimeric ions were observed with chloroform used as a solvent, while the [M + H]+ were observed as the base peak using ethylene dichloride. Spectra useful for the differentiation of isomers [CgH7O3Sn(C4Hg)3] were obtained by the formation of characteristic adduct ions, such as [M + EA + H]+ and [M + 2EA + H]+, with a reagent like 2-aminoethanol. Collision-induced dissociation (CID) spectra observed by ESI and LPI mass spectrometry were similar and provided less information than adduct ions did.     

Electrospray ionization tandem mass spectral analysis of oxidation products of precursors of sulfur mustards

Electrospray ionization tandem mass spectral (ESI-MSn) analysis of thiodiglycol, bis(2-hydroxyethylthio)alkanes (BHETAs) and their mono-, di-, tri-, and tetraoxygenated compounds was carried out to obtain their characteristic spectra for ESI-MS analysis. These compounds are important markers of chemical warfare agents, namely sulfur mustards. ESI-MSn (n > or = 3) analysis of a compound by collisionally induced dissociation in an ion trap gives rise to mass spectra that are somewhat similar to electron ionization mass spectra. These ESI-MSn spectra can be used for compound identification. Under ESI-MS and ESI-MS/MS the compounds mostly produced [M+NH4]+, [M+H]+ and [M+H--H2O]+ ions. Fragmentations of these even-electron precursors in the ion trap gave rise to characteristic product ions via neutral loss of O2, H2O, C2H4, HCHO, C2H4O, C2H4S, HSC2H4OH and C2H4SO. Fragmentation routes of these compounds are proposed that rationalize the formation of product ions in ESI-MSn analysis.     

Differentiation of isomeric substituted diaryl ethers by electron ionization and chemical ionization mass spectrometry

A series of isomeric substituted diaryl ethers, i.e., 2- or 4-NO2, 5- FC6H3OC6H4 (4-R), where R=H, COCH3, COOCH3, NO2, CHO, OCH3 etc., which comprise ortho and para isomers with respect to the position of the nitro group are studied under GC-EI-MS and CI-MS conditions. The EI mass spectra of ortho and para isomers show distinct fragment ions, where the [MOH]+ and [MOHO]+ ions specifically appeared in all spectra of the ortho isomers (I), whereas the para isomers (II) contain [MO]+ and [MNO]+ ions. The [MOHCO]+ and [MOHNO]+ ions in I, and [MNO2]+ ion in II are the other specific fragment ions observed but feasibility of these fragment ions are found to depend on the nature of the substituent (R). The substitution (R) effect is also clearly reflected in the formation of fragment ions due to sigma-cleavage process with or without hydrogen migration. Similar differences in the formation of specific fragment ions are also observed in ortho and para isomers of substituted aryl naphthyl ethers. The methane/CI of isomeric compounds resulted in the same set of fragment ions, but prominent differences are observed in the relative abundance of [MHNO]+, which is relatively higher in para isomers compared with corresponding ortho isomer.     

Letter: Influence of experimental conditions on electrospray ionization mass spectrometry of ferrocenylalkylazoles

Influence of experimental conditions on electrospray/ionization (ESI) mass spectra of ferrocene derivatives FcCHRAz (Fc = eta5-C5H5-Fe-eta5- C5H4; R = H, Az = benzimidazole; R = Ph, Az = 2-methylimidazole) has been investigated. The spectra of all the compounds revealed [M]+*, product of its fragmentation [FcCHR]+ as well as products of ion/molecular interactions (protonated molecule [MH]+, binuclear ion [(FcCHR)2 Az]+, dimeric ion [M2]+* and its protonated form [M2H]+). Relative abundances of these ions appreciably (more than one order) depend on experimental conditions: analyte concentration, temperature of heated capillary, spray voltage, flow rate of mobile phase and polarity of solvents. Established correlations allow the selection of optimum experimental conditions for registration of ESI mass spectra, as required by the application. If an unknown compound is to be identified, it is necessary to operate by using polar solvents, small concentration, low temperature of heated capillary, high spray voltage and flow rates. There are high-intensity binuclear and protonated dimeric ions in mass spectra under other conditions. It can give rise to wrong interpretation of the structure of investigated compound. At the same time, for study of ion-molecular processes by ESI-MS it is necessary to use concentrated samples in non-polar solvents. In this case the dependence of reaction products yields on temperature and flow rate of mobile phase must be investigated.     

Mass spectral studies on aryl-substituted N-carbamoyl/N-thiocarbamoyl narcotine and related compounds

Positive ion mass spectral fragmentation of new N-carbamoyl/N-thiocarbamoyl derivatives of narcotine and compounds closely related to it are reported and discussed. The techniques used include electron impact (EI), fast-atom bombardment (FAB), matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). Prominent peaks in the mass spectra of these compounds appear to involve C-C bond cleavage beta to the amine nitrogen with loss of the 4,5-dimethoxy(1H)isobenzofuranone moiety from their molecular ions, along with another prominent peak at m/z 382. No molecular ion peaks of these compounds were recorded in EI, whereas intense [M + H]+ ion peaks were observed in FAB and ESI spectra. MALDI also yielded [M + H]+ ion peaks in good agreement with FAB and ESI studies.     

Detection of oxidative species for 4-phenoxyphenol derivatives during the electrospray ionization process

Analyses by flow injection as well as liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) were performed with four 4-phenoxyphenol derivatives. When ambient temperature nitrogen gas was used to facilitate solvent evaporation, [M + H]+, [M + NH4]+, and [2M + NH4]+ ions were observed as the major ions. As the nitrogen gas temperature increased from ambient to 250 and 450 degrees C, [M]+*, [M - 1]+ and [M + 15]+ ions were the predominant ions. Heat-induced oxidation was found to be the primary source for the formation of oxidative species. Aqueous solvents were found to be essential for the formation of the [M + 15]+ ions. The [M]+* and [M + 15]+ ions were further characterized by tandem mass spectrometry. Based on the MS/MS data, it was proposed that the [M + 15]+ ions were the in-source generated 1,2-quinone ions.