由饱和酮与肼/醛腙的[3+2]/[2+3]环化反应区域选择性合成多取代吡唑（英文）

报道了一种经由二价铜催化饱和酮与肼或醛腙的串联反应合成1,3-二取代吡唑或1,3,4-三取代吡唑类化合物的简便和区域选择性新方法.从机理上看,1,3-二取代吡唑的生成经历了烯酮中间体的原位生成及其与肼的[3+2]环化反应,而1,3,4-三取代吡唑的生成则经历了烯酮中间体的原位生成及其与醛腙的[2+3]环化反应.与文献方法相比,该方法具有原料简单易得、底物适用范围广、区域选择性好、效率高、原子经济性优异等优势.     

新型吡唑啉酮衍生物的制备

以氢氧化钾为催化剂,1-苯基-3-甲基-吡唑啉-5-酮与取代苯甲醛亚胺反应合成了新型1-苯基-3-甲基-吡唑啉-5-酮衍生物——1-苯基-3-甲基-4-(1-N-氯乙胺基-1-取代苯基)甲基-吡唑啉-5-酮,其结构经1H NMR,IR,MS和元素分析表征。     

N-(取代对三氟甲基苯基)-N'-(1,3,5-三取代吡唑-4-羰基)硫脲的合成与生物活性

为了寻找高效低毒的农药,从3-甲基-1-取代苯基-5-吡唑酮出发,经过几步反应得到5-氯-3-甲基-1-取代苯基-4-吡唑羰基异硫氰酸酯.5-氯-3-甲基-1-取代苯基-4-吡唑羰基异硫氰酸酯分别与对三氟甲基苯胺和2,6-二氯-4-三氟甲基苯胺反应得到10个未见文献报道的N-(取代对三氟甲基苯基)-N'-(1,3,5-三取代吡唑-4-羰基)硫脲类化合物,其结构经元素分析,IR,1H NMR确证.初步生物活性测试结果表明部分化合物有一定的杀菌活性.     

无溶剂无催化剂微波促进下 1-苯基-3-甲基-5-吡唑啉酮与芳醛的反应研究

无溶剂无催化剂条件下,微波促进1-苯基-3-甲基-5-吡唑啉酮与芳醛的缩合反应选择不同辐射功率将分别得到4-芳亚甲基-3-甲基-1-苯基-5-吡唑啉酮和4,4′-芳亚甲基-双(1-苯基-3-甲基-5-吡唑啉酮),产率良好.产物结构经1H NMR,13CNMR和IR进行了表征.     

N-(取代对三氟甲基苯基)-N'-(1,3,5-三取代)吡唑-4-羰基硫脲的合成与生物活性

为了寻找高效低毒的农药, 从3-甲基-1-取代苯基-5-吡唑酮出发, 经过几步反应得到5-氯-3-甲基-1-取代苯基-4-吡唑羰基异硫氰酸酯. 5-氯-3-甲基-1-取代苯基-4-吡唑羰基异硫氰酸酯分别与对三氟甲基苯胺和2,6-二氯-4-三氟甲基苯胺反应得到10个未见文献报道的N-(取代对三氟甲基苯基)-N'-(1,3,5-三取代)吡唑-4-羰基硫脲类化合物, 其结构经元素分析, IR, ¹H NMR确证. 初步生物活性测试结果表明部分化合物有一定的杀菌活性.     

系列邻位取代苯基汞化合物亲电取代反应的等动力学相关分析

进行了系列的邻位取代苯基汞化合物亲电取代反应的等动力学相关分析研究,研究结果表明了用等动力学相关分析方法能够揭示有机化学反应中的主要影响因素.在邻位取代苯基氯化汞的S_E 2机理中,当碘为亲电试剂时,反应的主要影响因素是取代基的立体位阻;而当亲电试剂由碘变为氯化氢时,影响反应的主要因素则变为取代基的静电诱导效应.在邻位取代苯基氯化汞的S_E1机理中,相关分析结果证实了取代基的场效应是影响反应速率的主要因素.上述等动力学相关分析结果为邻位取代苯基氯化汞的亲电反应机理的研究提供了进一步的科学依据.     

N,N'-二(2-羟苄基)取代咪唑烷的合成、表征及抑菌活性

利用生物活性叠加原理,将"邻羟苯基"和"咪唑烷"分子片断有机结合,以水杨醛和乙二胺为起始原料,经缩合、NaBH4还原制得N,N'-二邻羟苄基乙二胺(2),进而与芳醛类化合物缩合关环,合成了8种N,N'-二(2-羟苄基)取代咪唑烷类化合物(3a～3h). 化合物的结构经1H NMR、IR、MS和元素分析等测试技术进行了表征. 结果表明,水杨醛与乙二胺的缩合反应,可专一性地生成对称双缩席夫碱化合物(1);芳醛上的取代基对缩合关环反应有显著影响,邻、对位吸电基可使芳醛的羰基活化,有利于缩合关环反应的进行,邻、对位供电基可使芳醛的羰基钝化,不利于缩合关环反应进行. 抑菌测试结果表明,质量分数为0.1%时,N,N'-二(2-羟苄基)取代咪唑烷化合物对不同菌株的抑菌活性具有明显的特异性,对白色念珠菌、大肠杆菌的抑菌率达100%.     

4-取代苯次甲亚胺-5-(1-苯基-3-甲基-5-氯吡唑)-2H-1,2,4-三唑-3-硫酮的合成

以乙醇为溶剂,冰醋酸为催化剂,4-氨基-5-(1-苯基-3-甲基-5-氯吡唑)-1,2,4-三唑-3-硫酮(1)与芳醛经缩合反应合成了7个新型的4-取代苯次甲亚胺-5-(1-苯基-3-甲基-5-氯吡唑)-4H-1,2,4-三唑-3-硫酮(3a~3g),收率66%~74%,其结构经1H NMR,IR及元素分析表征。合成4-(苯次甲亚胺)-5-(1-苯基-3-甲基-5-氯吡唑)-2H-1,2,4-三唑-3-硫酮(3a)的最佳反应条件为:以乙醇为溶剂,乙酸为催化剂,1 10 mmol,n(苯甲醛)∶n(1)=1.2,于75℃反应3 h,产率74%。     

取代8-羟基喹啉钌络合物催化Friedl?nder反应合成喹啉衍生物

Friedl?nder喹啉合成法是以邻胺基芳基醛或酮与有α-亚甲基的酮环化制备喹啉的反应,报道了一种喹啉钌络合物催化Friedl?nder法合成喹啉的方法.首先,以8-羟基喹啉钌络合物为催化剂,对模板反应邻氨基苯甲醇和苯乙酮合成2-苯基喹啉进行了反应条件优化实验.重点对比研究了8-羟基喹啉钌络合物配体上不同取代基对反应收率的影响,其中5-甲基-8-羟基喹啉(1e)钌络合物催化邻氨基苯甲醇和苯乙酮合成2-苯基喹啉获得了73%的最高收率.结合IR, UV以及密度泛函理论(DFT)计算讨论了配体结构与催化性能之间的关系.提出了β-H消除形成醛过渡态,交叉aldol反应再亚胺环化,最后脱水生成目标产物的可行机理.以(1e)₃Ru为催化剂,在优化的反应条件下进行了底物扩展研究,以69%～94%的收率合成了32个不同取代的喹啉衍生物,验证了方法的普适性.     

苯丙烯酰苯和甲肼反应的研究

α,β-不饱和醛或酮与单取代肼反应生成Δ~2-吡唑啉的反应机理,一般认为是通过1,2加成脱水生成腙,然后闭环而得.分离得到的中间体腙在酸性溶液中加热亦可得到Δ~2-吡唑啉.等人曾报道烯键上无取代基的α,β-不饱和酮与单取代肼反应是经过1,4加成所生成的β-肼基取代的酮闭环而得Δ~2-吡唑啉.我们在研究苯丙烯酰苯和甲肼的反应中,发现用略微过量的甲肼与苯丙烯酰苯(摩尔比     

Structural investigation on phenyl‐ and pyridin‐2‐ylamino(methylene)naphthalen‐2(3H)‐one. Substituent effects on the NMR chemical shifts

Schiff bases bearing phenyl and pyridyl groups were synthesized by condensation of appropriate amines with 2‐hydroxynaphthaldehyde. These Schiff bases were obtained as colored crystalline solids. The proton NMR spectra of these compounds showed a doublet for the NH protons indicating a keto tautomer for these Schiff bases. The pyridyl‐substituted Schiff bases containing hydroxyl moiety were found to show the most downfield shift for the NH protons in DMSO solvent, and this was rationalized due to the formation of a six‐ and five‐membered ring using hydrogen bonds for these two compounds. Correspondingly, the olefinic proton of the Schiff bases is also found to be a doublet due to coupling to the amine proton. These Schiff bases exhibited thermochromic properties. Detailed NMR spectral analysis for both the phenyl‐ and pyridyl‐substituted Schiff bases is presented. Copyright © 2010 John Wiley & Sons, Ltd.     

Polymeric Schiff Bases. III. Some Prototype Exchange Reactions of Schiff Bases

The amine moiety in Schiff bases can be exchanged quantitatively by another amine to yield new Schiff bases if the volatility of the replacing amine is lower than the derived amine, thereby allowing the latter to distilled from the reaction mass. This amine exchange was shown to be quantitative also for diamines and di-Schiff bases. Similarly, quantitative conversions were found for aldehydes and acetal exchanges with Schiff bases for both monofunctional and difunctional reactants. The bis exchange, involving two complementary Schiff bases, was quantitative also when the reactants were so selected that one of the new derived Schiff bases could be removed by distillation. The bis exchange was demonstrated with mono and di-Schiff bases.

Mechanisms are suggested for these Schiff base exchange reactions: attempts to isolate the proposed intermediates physically were unsuccessful; however spectroscopic evidence indicates the formation of intermediate compounds.

The Schiff base exchanges involving polyfunctional reactants are of interest in the synthesis of polymers.     

Structural and biological behaviors of some nonionic Schiff-base amphiphiles and their Cu(II) and Fe(III) metal complexes

Novel series of nonionic Schiff bases was synthesized and characterized using microelemental analysis, FTIR and (1)H NMR spectra. These Schiff bases and their complexes with Cu and Fe have been evaluated for their antibacterial activity against bacterial species such as Staphylococcus aureus, Pseudomonas aureus, Candida albi, Bacillus subtilis and Escherichia coli and their fungicidal activity against Aspcrgillus niger and Aspcrgillus flavus. The results of the biocidal activities showed high potent action of the synthesized Schiff bases towards both bacteria and fungi. Furthermore, complexation of these Schiff bases by Cu(II) and Fe(III) show the metal complexes to be more antibacterial and antifungal than the Schiff bases. The results were correlated to the surface activity and the transition metal type. The mode of action of these complexes was discussed.     

溶剂和分子结构对席夫碱分子在有机凝胶中的荧光增强和超分子手性的影响

研究了在有机胶凝剂中掺杂的席夫碱化合物的结构和性质. 实验发现, 虽然席夫碱分子单独不能在有机溶剂中形成凝胶, 当其与一种胶凝剂N,N’-双十八烷基-L-Boc-谷氨酸混合时, 它们在二甲基亚砜或甲苯中形成透明的有机凝胶. 与相应的溶液相比, 观察到在有机凝胶中的荧光增强现象, 并且这一增强与席夫碱的结构有密切关系. 在二甲基亚砜的有机凝胶中, 观察到带有长烷基链的席夫碱具有诱导手性. 表明通过凝胶的形成, 胶凝剂的手性能传递到带有长链的席夫碱上.     

Effect of Solvent and Molecular Structure on the Enhanced Fluorescence and Supramolecular Chirality of Schiff Bases in Organogels

The structures and properties of some Schiff base compounds doped in organogels were investigated. It was found that although individual Schiff bases could not form organogels with organic solvents, they can gel by mixing with an organogelator, N,N′-bisoctadecyl-L-Boc-glutamic-diamide, which formed transparent organogels in dimethyl sulfoxide (DMSO) or toluene (Tol). The enhancement of doping Schiff bases fluorescence in the organogel was observed in comparison with that of the corresponding solution. Furthermore, in the DMSO organogel, the induced chirality was obtained from the doping Schiff base with long alkyl chain. In contrast, the Schiff bases without long alkyl chain could not form supramolecular chiral assemblies in organogel. It was suggested that through gel formation the chirality of the gelator could be transferred to the Schiff base through hydrophobic interaction among the long alkyl chains.     

Molecular structures and stability constants of gossypol and its aza-derivative complexes with silver(I) cations studied by potentiometric, ESI MS, NMR, and AM1d semiempirical methods

Stability constants of complexes formed by gossypol and by ten of its Schiff bases with Ag (+) cations were determined by the potentiometric method. The potentiometric and ESI MS experiments indicate the formation of AgL (+) and Ag 2L (2+) complexes between the Schiff bases G1-G7 and Ag (+) cations as well as the formation of AgL (+), Ag 2L (2+), AgL 2 (+) and Ag 3L 2 (3+) complexes between the Schiff bases G8-G10 and Ag (+) cations. The highest stability constant was found for the AgL (+) complex of G8 Schiff base and the lowest one for the AgL (+) complex of G molecule. The (13)C NMR spectra of mixtures between G and AgClO 4 as well as G1-G10 and AgClO 4 indicate that the complexation of the Ag (+) cations is exclusively realized by the aldehyde-aldehyde tautomer of gossypol and by the enamine-enamine form of gossypol Schiff bases, respectively. We show that the main coordination sites for the Ag (+) metal cations are either the oxygen or the nitrogen atoms of the amine parts of the Schiff bases of gossypol. The energetically most favorable structures of the Ag (+) complexes with gossypol (G) or with the gossypol Schiff bases (G1-G10) were calculated and visualized by the AM1d method at an semiempirical level of theory.     

Synthesis of novel Schiff base doped sol–gel silicas

Sulfonamide Schiff bases were doped uniformly in silica sol–gels prepared from liquid precursors by a fast and easy way at room temperature and processed to form xerogels. Schiff bases are efficient chelating agents, bioactive and catalytically active compounds. The structures of the newly synthesized Schiff base doped xerogels were elucidated by their physical (morphology, surface area, porosity), spectral (FTIR) and analytical (CHNSO/Si) data. The powder X-ray diffraction studies were carried out to confirm the formation of single phase. Characterization confirmed that Schiff base molecules are entrapped inside the pores as well as physically bound onto the silica surface. All Schiff base doped xerogels are stable mesoporous materials showing hydrophilic properties. Loadings of Schiff bases from 0.10 to 0.23 g/g of xerogel were obtained resulting amorphous materials. The doping of Schiff bases with xerogel caused change in surface area, pore volume and pore diameter of xerogel without damaging the main framework of siliceous skeleton. Morphology and colour of xerogel was also changed after doping. The entrapment of Schiff bases in xerogel caused increase in their decomposition temperatures. The final Schiff base doped xerogels show remarkable thermal stability.     

Enrichment of copper and nickel with solid phase extraction using multiwalled carbon nanotubes modified with Schiff bases

The behaviour of some Schiff bases in the presence of metal ions is very selective in complex formation. In this study, new, selective and easily prepared adsorbent materials have been developed. Multiwalled carbon nanotubes (MWCNTs) are quite suitable as supporting material for preparation of new solid phase adsorbents modified with Schiff bases due to their selective nature. Different Schiff bases were designed and synthesised as adsorbent agents for Ni(II) and Cu(II) ions, according to the literature, and MWCNTs were modified with these Schiff bases. The modification of CNTs was performed by adsorption from the alcoholic solution of Schiff base. The measurements of Ni(II) and Cu(II) ions were carried out using ICP-MS. Different parameters such as pH, model and eluent solution flow rates, eluent type, amount of ligand, sample volume and effect of foreign ions, which have an effect upon recovery of analytes, were investigated. The obtained results indicated that enrichment can be done with six modified adsorbent materials for Cu(II) at pH 9 and two modified adsorbent materials for Ni(II) at pH 8. It was concluded that four adsorbent materials were selective only for the enrichment of Cu(II). Merely one modified adsorbent material was noneligible for the enrichment of Cu(II) and Ni(II). The solid phase adsorbents prepared by modification with two of the Schiff bases used in this study showed an enrichment factor of 80 for both metal ions, whereas the solid phase adsorbents prepared by modification with four of the Schiff bases showed an enrichment factor of 40 for Cu(II) ions. The confirmation of the developed method was tested with certified reference materials with satisfactory results.     

α-(5—四唑基)氨基烃基膦酸酯的合成及其生物活性

合成了12个新的5—氨基—1H—1，2，3，4—四唑的Schiff碱，而后与亚磷酸 二乙酯反应，合成出了12个新的含四唑基的α-氨基烃基膦酸酯，通过IR，^1H NMR，^31P NMR和元素分析证实了它们的结构．生物活性实验证明，一些目标化合 物具有良好的植物生长调节活性，其中氯代苯甲醛和吲哚甲醛的Schiff碱生成的α -氨基烃基膦酸酯的生长素活性更好。     

左旋多巴Schiff碱的合成及其不对称相转移催化烷基化

通过天然左旋多巴与不同芳香醛酮的反应, 合成出5种左旋多巴Schiff碱5a～5e, 其中5c～5e是文献中未见报道的化合物. 然后以这些左旋多巴Schiff碱为底物, 通过不对称相转移催化烷基化反应, 合成出具有光学活性的甲基多巴及其类似物. 同时, 研究探讨了不同相转移催化剂及不同反应条件对左旋多巴Schiff碱甲基化反应的影响.