四氢叶酸辅酶模型1, 2, 3-三取代咪唑啉盐的质谱裂解行为

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。在所有实验中均有 ｍ／ｚ ＝ １２７（ Ｉ＋ ） 的离子峰和有机正离子 Ａ 峰存在,表明化合物１ 和２ 均为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： Ｃ２ Ｎ３ 键和 Ｃ５ Ｎ１ 键同时断裂产生 Ｇ 离子碎片,以及 Ｃ２ Ｎ３ 键和 Ｃ４ Ｃ５ 键同时断裂产生 Ｈ 离子碎片。由于化合物１ 和２ 环上所连接的取代基不同而导致了其质谱裂解方式和程度的差异。化合物２ 的有机正离子 Ａ部分较稳定,质谱中表现为基峰,其 Ｅ, Ｆ 离子峰很弱;化合物１ 的有机正离子 Ａ 稳定性差,其相对丰度很小,其 Ｅ, Ｆ 离子峰较强。化合物１ｃ ,１ｄ ,１ｅ 的质谱中出现了比 Ａ 离子少三个单位的 Ｃ 离子峰,这是一种较特殊的裂解方式。     

2—羟基2‘烷氧基—1,1’—联萘化合物的^1HMNR研究

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。     

四氢叶酸辅酶模型化合物的研究：I.碘化1,2—二甲基—3—芳磺酰基—△^2 …

合成了四氢叶酸辅酶甲酸态的３个模型化合物,即碘化１,２－二甲基－３芳磺酰基（芳基＝ｐ－ＣＨ３Ｃ６Ｈ４,Ｃ６Ｈ５,ｐ－ＣｌＣ６Ｈ４）－△＾２－咪唑啉,研究了其还原和水解反应。     

Grignard试剂同6,6—二烷基富烯反应的研究

烯丙基卤化镁和环戊二烯基溴化镁同６，６－二烷基富烯分别进行富烯环外双键的加成和还原反庆，生成的取代环戊二烯基负离子用（ＣｐＴｉＣｌ２）２Ｏ（Ｃｐ＝环戊二烯基）或ＴｉＣｌ４配合，合成式为Ｃｐ（Ｃ６Ｈ４－ＣＲＲ＾１－ＣＨ２Ｃｈ－ＣＨ２）ＴｉＣｌ２和（Ｃ６Ｈ４ＣＨＲＲ＾１）２ＴｉＣｌ２的化合物，对烯丙基卤化镁、环戊二烯基溴化镁同富烯的反应机理进行了探讨。     

2－羟基2＇烷氧基－1，1＇－联萘化合物的~1HMNR研究

研究了２－羟基－２＇－异丙氧基－１。１－联萘（３）等联萘化合物的~１ＨＮＭＲ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［１］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。     

芳氨基硫脲类化合物的质谱研究（Ⅱ）

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。     

多二茂铁基二氮杂己烷及其过渡金属配合物的合成

乙二胺与二茂铁甲醛或双二茂铁甲基氟硼酸盐反应，合成了１，６－二（二茂铁基）－２，５－二氮杂己烷和１，１，６，６－四（二茂铁基）－２，５－二氮己烷，它们与过渡金属（Ｆｅ＾２＋，Ｃｏ＾２＋，Ｎｉ＾２＋，Ｃｕ＾２＋，Ｚｎ＾２＋）盐在乙醇或乙醇－二氯甲烷中反应，是１４种过渡金属配合物，对这些化合物进行了表征，二种配体及其铜配合物用作复合固体推进剂的燃速调节剂时，基本不迁移，而燃速催化效率均超过辛基二茂铁。     

6,6—二烷基富烯与苄基钠的反应研究：取代茂钛,锆化合物…

苄基钠与６，６－二烷基富烯及６，６－ｎ亚甲基富烯（ｎ＝４，５，６）皆发生富烯环外双键的加成反应。产生的取代环戊二烯基负离子与ＴｉＣｌ４、ＺｒＣｌｒ及（ＣｐＴｉＣｌ２）２Ｏ络合，合成出２２种新的含或不含手性碳取代茂铁、锆化合物。讨论了反应机理及＾１Ｈ ＮＭＲ谱。     

甲基取代的甲酸态的四氢叶酸辅酶模型的合成及其取代碳 …

以乙二胺和乙酰胺为原料，经４步反应合成了碘化１，２－二甲基－３－间（或对）－硝基苯磺酰基咪唑啉（２ａ，２ｂ）以２ａ和２ｂ作为甲基取代的甲酸态四氢叶酸辅酶模型，同单亲核中心的氮亲核体（对甲苯胺，对甲氧基苯胺等）和碳亲核体（丙二腈）反应得到次惭基单元（ＣＨ３－Ｃ≤）转移的中间体产物，与双亲核中心的亲核体（邻苯二胺，邻氨基酚）反应得到次乙基单元完全转移的产物。     

1－硫脲乙基－2－芳基－2－咪唑啉化合物的合成

１－硫脲乙基－２－芳基－２－咪唑啉化合物的合成刘运廷，章荣玲（山东工业大学数理系济南，２５００１４）关键词咪唑啉，硫脲基，芳基，合成咪唑啉衍生物由于具有缓蚀、杀菌、抗癌等活性而迅速发展￣［１，５］。作者曾研究过各种咪唑啉衍生物的合成￣［６］，系采用通...     

新的四氢叶酸辅酶模型及与亲核试剂反应生成物的核磁共振研究

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。     

A 19F NMR study of the transmission of electronic effects in triarylantimony and triarylbismuth compounds. A comparison with the nitrogen- and carbon-containing analogues

A ¹⁹F NMR study of the transmission of electronic effects has been made for the systems Ar₂EC₆H₄F-4 (E = Sb, Bi, CH, N). The fluorine chemical shifts obtained are correlated with the polar constants (Σσ^o and Σσ) of the substituents, suggesting that electronic effects are transmitted through the SbC_ar, BiC_ar and CC_ar bonds predominantly by an inductive mechanism, whereas the transmission through the NC_ar bonds is contributed to significantly by classical resonance effects due to competitive conjugation of the lone pair with the aromatic rings, and the substituents therein. A dual parameter correlation of the fluorine chemical shifts with the inductive (σ_I) and resonance (σ^o_R and σ_R) parameters of the substituents in the aromatic rings has led to similar conclusions. The inductive transmission through the bridging Sb and Bi atoms has been assigned to the absence of conjugation of lone pair and vacant d-orbitals of the metals with π-electron systems of the aromatic rings. On the basis of the values of the ? coefficients for the correlation equations obtained it has been established that the transmitting ability of the BiC_ar bonds is close to that of the C_alC_ar bonds and considerably lower than the transmitting ability of the NC_ar bonds.     

Structural characterization of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis(2-methoxyethyl) -4,5-bis(2,4,6-trimethylphenyl)imidazolinium hexafluorophosphate

The crystal and molecular structure of the N,N′-bis(2-methoxyethyl)-4,5-bis(2,4,6-trimethylphenyl)- imidazolinium hexafluorophosphate, which is the first example of 1,3- and 4,5-disubstituted imidazolinium salts, have been determined and characterized by X-ray single crystal diffraction technique,¹H, ¹³C, ³¹P and ¹⁹F NMR spectroscopy. The compound, C₂₇H₃₉N₂O₂ ⁺·PF₆ ^?, crystallizes in the orthorhombic space group Pba2 with a = 15.8139(4) Å, b = 22.9346(7) Å, c = 8.069(3) Å. Two charge-assisted C–H\(\cdots\)F type crystal packing interactions between the imidazolinium C–H bonds and the F atoms of hexafluorophosphate counteranions build up zigzag chains along a-axis of the unit cell and indicate that the C–H bonds of the imidazolinium ring are also polarized. In addition, the title salt was modeled by DFT calculations in order to verify charge transfer mechanism observed in its imidazolinium ring.     

Evaluation of fast atom bombardment mass spectrometric and low-energy collisional activation tandem mass spectrometric data for the structural elucidation of bisbenzylisoquinoline alkaloids

The fast atom bombardment (FAB) mass spectra and low-energy collisional activation mass spectra of ions generated under FAB were investigated for twelve bisbenzylisoquinoline (BBI) alkaloids. The relative molecular mass of the free base and diquaternary BBI alkaloids can be obtained from FAB data. However, monoquaternary ammonium salts produce only an [M — X]⁺ ion and the relative molecular mass cannot be determined. For Type A (single ether linkage) BBI alkaloids, fragmentation occurs primarily from benzylic and ether cleavages. Thus, the total number of aromatic substituents (OH, OCH₃ or OCH₂O) can be determined for rings A-B, C-D, E and F. For Type B (two either linkages) BBI alkaloids, fragmentation occurs primarily from double benzylic cleavages. Hence only the total number of aromatic substituents can be determined for the upper half of the Type B BBI alkaloids, i.e. rings A-B and C-D. An unknown alkaloid was examined to illustrate the utility of the fragmentation schemes.     

Thermal analysis study of imidazolinium and some benzimid azolium salts by TG

The imidazolinium and benzimidazolium bromide salts with pentafluor substituents on N atom were synthesized. The structures of imidazolinium and benzimidazolium bromide salts obtained were conformed by ¹H and ¹³C NMR, ¹⁹F NMR and elemental analysis. It was found that pyrolytic decomposition occurs with melting in salts. The imidazolinium and benzimidazolium bromide salts were studied by TG-DTG and DTA from ambient temperature to 1000°C in nitrogen atmosphere. The decomposition occurred mainly in one stage and the values of activation energy E, frequency factor A, reaction order n, enthalpy change ΔH ^#, entropy change ΔS ^# and Gibbs free energy ΔG ^#, of the thermal decomposition were calculated by means of Coats-Redfern (CR), MacCallum-Tanner (MC) and van Krevelen (vK) methods. The activation energy value obtained by CR and MC methods were in good agreement with each other while those obtained by vK were found to be 10–12 kJ mol⁻¹ larger.     

Molecular and crystal structure of (pyrazin-1-ium-1-yl)(perfluoropyridin-4-yl) and (4,4′-bipyridin-1-ium-1-yl)(perfluoropyridin-4-yl)amides

The single crystal X-ray diffraction study of (pyrazin-1-ium-1-yl)(perfluoropyridin-4-yl) and (4,4??-bipyridin)-1-ium-1-yl(perfluoropyridin-4-yl)amides is performed. In all cases, the N⁺-N^? bond length is less than that of the single N_planar.-N_planar. bond, but considerably more than that of the double N=N bond, which indicates a weak involvement of the N^? lone pair of the C₅NF₄N^? group in conjugation with pyrazine or bipyridine moieties. Quantum chemical calculations by DFT/(PBE/L1), B3LYP/L1, and RI-MP2/L1 methods provide the geometry of amides similar to the experimental one. Crystals of (pyrazin-1-ium-1-yl)(perfluoropyridin-4-yl)amide form stacks mainly through F-?? interactions. The stacks are joined in 3D architecture by weak C-H??N and C-H??F hydrogen bonds. In the case of (4,4??-bipyridin)-1-ium-1-yl(perfluoropyridin-4-yl)amide crystals, an essential role is played by the ?? stacking interactions of heteroaromatic rings.     

Dediazoniation of Arenediazonium Ions. Part XXII. Reactions of 2, 6-Dialkyl-Substituted Benzenediazonium Ions in Super Acids,Acetonitrile and Acetone

Reactions of 2,4,6-trimethylbenzenediazonium ( 1 ), 2,6-diethylbenzenediazonium ( 2 ) and 2,6-diisopropylbenzenediazonium ( 3 ) tetrafluoroborates were studied in magic acid, SbF₅/SO₂ClF, acetonitrile and acetone by ¹H-NMR and by analysis of the dediazoniation products. The N_α-N_β rearrangement of β-N¹⁵-labelled tetrafluoroborates 1–3 was followed by ¹⁵N-NMR of the corresponding arylazonaphthols, as well as by MS analysis of the anilines obtained by reduction of the azo compounds. Diazonium salts 2 and 3 were synthesized for the first time and the steric effect of substituents at C(2) and C(6) on the reactions under study is discussed. All the results obtained can be rationalized by heterolytic dediazoniation of diazonium salts 1 – 3 and product formation from the corresponding aryl cations.     

A mass spectrometric method to determine activities of enzymes involved in polyamine catabolism

An analytical method for the determination of three polyamines (putrescine, spermidine, and spermine) and five acetylpolyamines [N¹-acetylspermidine (N¹AcSpd), N⁸-acetylspermidine (N⁸AcSpd), N¹-acetylspermine, N¹,N⁸-diacetylspermidine, and N¹,N¹²-diacetylspermine] involved in the polyamine catabolic pathway has been developed using a hybrid tandem mass spectrometer. Heptafluorobutyryl (HFB) derivatives of these compounds and respective internal standards labeled with stable isotopes were analyzed simultaneously by TOF MS, based on peak areas appearing at appropriate m/z values. The isomers, N¹AcSpd and N⁸AcSpd were determined from their fragment ions, the acetylamidopropyl and acetylamidobutyl groups, respectively, using MS/MS with ¹³C₂-N¹AcSpd and ¹³C₂-N⁸AcSpd which have the ¹³C₂-acetyl group as an internal standard. The TOF MS method was successfully applied to measure the activity of enzymes involved in polyamine catabolic pathways, namely N¹-acetylpolyamine oxidase (APAO), spermine oxidase (SMO), and spermidine/spermine N¹-acetyltransferase (SSAT). The following natural substrates and products labeled with stable isotopes considering the application to biological samples were identified; for APAO, [4,9,12-¹⁵N₃]-N¹-acetylspermine and [1,4,8-¹⁵N₃]spermidine (¹⁵N₃-Spd), respectively; for SMO, [1,4,8,12-¹⁵N₄]spermine and ¹⁵N₃-Spd, respectively; and for SSAT, ¹⁵N₃-Spd and [1,4,8-¹⁵N₃]-N¹-acetylspermidine, respectively.     

Tunable Fullerene Affinity of Cages,Bowls and Rings Assembled by PdII Coordination Sphere Engineering

For metal-mediated host compounds, the development of strategies to reduce symmetry and introduce multiple functionalities in a non-statistical way is a challenging task. We show that the introduction of steric stress around the coordination environment of square-planar Pd^II cations and bis-monodentate nitrogen donor ligands allows to control the size and shape of the assembled product, from [Pd₂L₄] cages over [Pd₂L₃] bowl-shaped structures to [Pd₂L₂] rings. Therefore, banana-shaped ligand backbones were equipped with pyridines, two different quinoline isomers and acridine, the latter three introducing steric congestion through hydrogen substituents on annelated benzene rings. Differing behavior of the four resulting hosts towards the binding of C₆₀ and C₇₀ fullerenes was studied and related to structural differences by NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. The three cages based on pyridine, 6-quinoline or 3-quinoline donors were found to either bind C₆₀, C₇₀ or no fullerene at all.