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1.
讨论了1,2,3-不对称取代咪唑啉盐各种离子的生成途径以及取代基对裂解方式的影响并分析了该类化合物的主要裂解方式。在所有中的均m/z=127(1^+)的离子峰和有机正离子A峰存在,表明化合物1和2均有机正离子和碘离子形成的盐。化合物1和2的质谱有相似的裂解方式;有机正离子发生失掉氮原子上的一个取代基而保留咪唑啉环产生D,E,F离子的裂解方式。更重要的是咪唑啉环有相同的裂解方式:C^2-N^3键和C  相似文献   

2.
本文报道了五种新的芳氨基硫脲类化合物,即1-(4-溴-2-羧基苯基)-4-烷基氨基硫脲的电子轰击质谱(EIMS)。结果表明,该类化合物的分子离子峰(M+)很弱,但却具有效强的[M-H]+峰。分子离子的断裂以N-N键和C-N键的断裂为主,并伴随着六员环或四员环过渡态氢重排,生成相应的芳氨基正离子和芳肼基正离子,这两种离子继续失水或失其它小分子,从而形成一系列特征离子,包括骨架重排离子。  相似文献   

3.
甘草次酸及其衍生物的质谱研究   总被引:1,自引:0,他引:1  
本文通过应用EI质谱和高分辨质谱对甘草次酸及其衍生物进行研究,阐明了分子离子的各种裂解、重排机理,讨论了主要离子的形成过程以及不同取代基对分子离子峰强度的影响。并用软电离手段──快原子轰击正、负离子(PFAB和NFAB)质谱,使EI谱上不出现分子离子峰的两个化合物而获得满意结果。  相似文献   

4.
钱旭红  钱枫 《分析化学》1994,22(9):942-944
本文报道了三个由三氟乙氧基取代的氯代三氟甲基吡啶化合物的核磁共振氢谱及电子轰击质谱,结果表明,与乙氧基化合物相对照,在H-NMR中,由于三氟甲基的强吸电子作用,其次甲基移向低场,并给出了一组具有较大偶合常数的四得峰。在EIMS中,均存在较多的架重排离子峰,其中C-O,C-F,C-CF3键断裂及失法CO形成的五元,四元含氮杂环离子是重要质谱特征。  相似文献   

5.
2—羟基2‘烷氧基—1,1’—联萘化合物的^1HMNR研究   总被引:1,自引:1,他引:0  
研究了2-羟基-2'-异丙氧基-1,1-联萘(3)等联萘化合物^1H NMR谱或COSY谱,此类化合物因2及2'位取代基不同,两个萘环上同位质子不再等价,萘环质子峰增至12组。化合物3^1HNMR谱峰的归属表明,萘环环电流各向异性对另一萘环质子的屏蔽作用与作者早期研究结果一致。2(或2')位取代基上的质子的化学位移也与另一萘环平面相对位置有关。  相似文献   

6.
通过2 ,3 ,4 ,6四 O乙酰 基β D吡 喃型 葡萄 糖 异硫 氰酸 酯( 3) 和 2 ,3 ,4三 O乙 酰基β D吡 喃型木糖 异硫氰酸 酯( 4) 与 取代的芳 基酰 肼(5) 的亲 核加 成反 应合 成了 10 个 1芳酰 基4(1′ N2′,3′,4′,6′四 O乙 酰基β D 吡 喃 型葡 萄 糖 基) 氨基 硫 脲(6) 和7 个 1芳 酰 基4( 1′ N2′,3′,4′三 O乙酰 基β D吡喃 型木糖 基) 氨基硫 脲( 7) ,并 经脱除乙 酰基得 到10 个1芳 酰基4(1′ Nβ D吡喃型 葡萄糖 基) 氨基硫 脲(8) 和 7 个1芳酰 基4(1′ Nβ D吡喃型 木糖 基) 氨基 硫脲( 9) , 所得化合物 经元素 分析, I R,1 H N M R 确证 了结构  相似文献   

7.
采用XAFS方法分别对Co的近边结构和配位状态进行了详细的表征.XANES的结果表明,所有样品中Co均处于不对称的配位环境中,在吸收阈值处,形成了1s→4p吸收峰,并且该峰发生了分裂,尤其是Co/γ-Al2O3分裂现象最为明显.对于Co-M/γ-Al2O3(M=Pt,Pd,Rh),这种不对称性可能来源于Co的高度分散性及贵金属与Co之间的相互作用,而对于Co/γ-Al2O3,则与四面体配位的Co2+离子有关.EXAFS结果表明,含贵金属样品中,Co均以零价形式存在,和标样Co粉相比,Co-Co键长略有增加,而配位数较标样下降许多.配位数的下降,表明Co具有高度的分散性,而键长的增加可能是贵金属与Co的相互作用削弱了Co-Co键引起的.  相似文献   

8.
芳基肟胺化合物与取代环丙烷羧酸酰氯在Et3N作用下室温反应得到芳基肟胺菊酯类化合物,在甲苯中回流反应则得到含取代环丙烷基的1,2,4-恶二唑衍生物,前者在甲苯中回流,HOAc作催化剂时发生环化反应也生成1,2,4-恶二唑衍生物,初步生物活性测试表明这些化合物具有的杀菌和除草活性。  相似文献   

9.
芳基肟胺化合物与取代环丙烷羧酸酰氯在Et_3N作用下室温反应得到芳基肟胺菊酯类化合物,在甲苯中回流反应则得到含取代环丙烷基的1,2,4- 二唑衍生物。前者在甲苯中回流,HOAc作催化剂时发生环化反应也生成1,2,4- 二唑衍生物.初步生物活性测试表明这些化合物具有的杀菌和除草活性.  相似文献   

10.
PARAMAGNETICANDDIAMAGNETICDICOPPER(Ⅱ)COMPLEXESWITHDI-SCHIFFBASEDERIVEDFROM2-HYDROXY-1-NAPHTHALDEHYDEAND1,3-DIANINO-2-PROPANOL...  相似文献   

11.
对新合成的四氢叶酸辅酶模型碘化1,2二甲基3对甲氧苯磺酰基咪唑啉及与亲核试剂反应后生成的产物进行了1HNMR谱的研究,通过化学位移及偶合常数研究探讨其规律性。  相似文献   

12.
以2位环己基取代苯并咪唑盐作为甲酸氧化态的四氢叶酸辅酶模型, 与亲核Grignard试剂作用, 将甲酸氧化态的一碳单元转移给亲核试剂, 成功地实现了6类具有潜在应用价值的环己基甲酮的绿色仿生合成, 其结构用元素分析、1H NMR、IR和MS等方法进行了表征, 并对反应机理和反应条件进行了讨论.  相似文献   

13.
本工作模拟了四氢叶酸辅酶的结构和反应性能, 合成了模型化合物碘化1, 2-二甲基-3-对甲氧苯磺酰基咪唑啉, 研究了模型化合物与单官能团亲核体、双官能团亲核体相作用, 以甲酸、甲醛氧化态转移取代一碳单元[≡C-CH~3, =C(CH~3)CH~2NO~2]的反应, 部分反应生成了咔啉类生物碱衍生物和其它杂环类化合物。  相似文献   

14.
The title compound (2E,3E)-N1,N2-bis(2,3,4-trimethoxy-6-methylbenzylidene)- ethane-l,2-diamine (C24H32N2O6, Mr = 444.52) was synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P2/c, with a = 8.5480(10), b = 9.3710(12), c = 15.280(2)A, β = 90.780(2)°, V= 1223.9(3)A3, Z = 2, Dc= 1.206 g/cm3, 2 = 0.71073A,μ(MoKa) = 0.087 mm^-1, F(000) = 476, the final R = 0.0680 and wR = 0.1450 for 2144 observed reflections with I 〉 2σ(I). X-ray diffraction analysis reveals that the molecule adopts an E configuration about the central C=N functional bond. The phenyl rings of two 2,3,4-trimethoxy-6-methylbenzaldehyde groups are symmetrically parallel. The molecules are linked through C-H…O hydrogen bonding interactions. The title compound possesses moderate antibacterial activity.  相似文献   

15.
A palladium-catalyzed multicomponent synthesis of imidazolinium carboxylates and imidazolines is described. The palladium catalyst [Pd(CH(R(1))N(R(2))COR(3))Cl](2), or [Pd(allyl)Cl](2), with P(t-Bu)(2)(2-biphenyl) can mediate the simultaneous coupling of two imines, acid chloride, and carbon monoxide into substituted imidazolinium carboxylates within hours under mild conditions (45 °C, 4 atm of CO). The reaction proceeds in good yield with aryl-, heteroaryl-, and alkyl-substituted acid chlorides, as well as variously functionalized imines. Imidazolines are formed via the initial generation of Mu?nchnone intermediates, followed by their cycloaddition with an in situ generated protonated imine. The addition of an amine base can intercept catalysis at Münchnone formation, which allows the subsequent cycloaddition of a second imine. The latter provides a route for the assembly of complex, polysubstituted imidazolinium carboxylates with independent control of all five substituents. The subsequent removal of the nitrogen substituent(s) provides an overall synthesis of imidazolines.  相似文献   

16.
The title compound (E)-N1,N4-bis(2,3,4-trimethoxy-6-methylbenzylidene) butane- 1,4- diamine (C26H36N2O6, Mr = 472.57) was synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to triclinic, space group C2/c with a = 36.102(4), b = 5.6620(11), c = 13.015(2)A,β = 105.491 (2)°, V = 2563.7(7)A3, Z = 4, Dc = 1.224 g/cm3, 2 = 0.71073 A,μ(MoKα) = 0.087 mm^-1, F(000) = 1016, the final R = 0.0456 and wR = 0.1257 for 2255 observed reflections with I 〉 2σ(I). X-ray diffraction analysis reveals that the molecule adopts an E configuration about the central C=N functional bond. The phenyl rings of two 2,3,4-trimethoxy-6-methylbenzaldehyde groups are parallel by symmetry. The molecules are linked through π-π and C-H…π stacking interactions and C-H…O hydrogen bonding interactions. The title compound possesses moderate antibacterial activity.  相似文献   

17.
Summary 1. The mass spectra of epimeric tertiary alcohols of the D-homoestrane series and the acetates and 17a-trideuteromethyl analogs corresponding to them have been studied. A new approach to the determination of the configuration of tertiary steroid alcohols has been proposed in which the trideuteromethyl analogs of the epimeric alcohols are subjected to mass-spectrometric analysis. The presence in the mass spectrum of an epimer of a doublet of peaks M-H2O and M-DOH indicates the a-alkyl-e-OH configuration, while the presence in the spectrum of an intense M-H2O peak shows the presence of an axial OH group.2. The mass spectra of the epimeric secondary alcohols of the pregnane series taken with the use of a system of introducing the sample into the ion source has been investigated. It has been shown that the mass spectra of alcohols containing an a-OH group in rings C and D differ markedly from the spectra of the e-OH epimers with respect to the ratio of the intensities of the peaks M-H2O and M+.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 6, pp. 369–382, 1967  相似文献   

18.
The conformational preferences and infrared and ultraviolet spectral signatures of two model beta-peptides, Ac-beta3-hPhe-beta3-hAla-NHMe (1) and Ac-beta3-hAla-beta3-hPhe-NHMe (2), have been explored under jet-cooled, isolated-molecule conditions. The mass-resolved, resonant two-photon ionization spectra of the two molecules were recorded in the region of the S0-S1 origin of the phenyl substituents (37,200-37,800 cm(-1)). UV-UV hole-burning spectroscopy was used to determine the ultraviolet spectral signatures of five conformational isomers of both 1 and 2. Transitions due to two conformers (labeled A and B) dominate the R2PI spectra of each molecule, while the other three are minor conformers (C-E) with transitions a factor of 3-5 smaller. Resonant ion-dip infrared spectroscopy was used to obtain single-conformation infrared spectra in the 3300-3700 cm(-1) region. The infrared spectra showed patterns of NH stretch transitions characteristic of the number and type of intramolecular H-bonds present in the beta-peptide backbone. For comparison with experiment, full optimizations of low-lying minima of both molecules were carried out at DFT B3LYP/6-31+G*, followed by single point MP2/6-31+G* and selected MP2/aug-cc-pVDZ calculations at the DFT optimized geometries. Calculated harmonic vibrational frequencies and infrared intensities for the amide NH stretch vibrations were used to determine the beta-peptide backbone structures for nine of the ten observed conformers. Conformers 1B, 1D, and 2A were assigned to double ring structures containing two C6 H-bonded rings (C6a/C6a), conformers 1A and 2B are C10 single H-bonded rings, conformers 1C and 2D are double ring structures composed of two C8 H-bonded rings (C8/C8), and conformers 1E and 2E are double ring/double acceptor structures in which two NH groups H-bond to the same C=O group, thereby weakening both H-bonds. Both 1E and 2E are tentatively assigned to C6/C8 double ring/double acceptor structures, although C8/C12 structures cannot be ruled out unequivocally. Finally, no firm conformational assignment has been made for conformer 2C whose unusual infrared spectrum contains one very strong H-bond with NH stretch frequency at 3309 cm(-1), a second H-bonded NH stretch fundamental of more typical value (3399 cm(-1)), and a third fundamental at 3440 cm(-1), below that typical of a branched-chain free NH. The single conformation spectra provide characteristic wavenumber ranges for the amide NH stretch fundamentals ascribed to C6 (3378-3415 cm(-1)), C8 (3339-3369 cm(-1)), and C10 (3381-3390 cm(-1)) H-bonded rings.  相似文献   

19.
Two novel 27-norergostanol steroids, panthogenins A (1) and B (2), possessing unusual rings E and F featuring a ketal moiety at C-25 were isolated from rhizomes ofDioscorea panthaica. Their structures and relative configurations were elucidated by extensive spectroscopic methods including 1D and 2D NMR techniques, and the structure of panthogenin A was further confirmed by X-ray crystallography. Both compounds showed potent in vitro insulin sensitizing activity.  相似文献   

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