新型吡唑Schiff碱及金属配合物的合成和抑菌活性

以3-氨基-4-氰基吡唑和芳醛为原料合成了10个新型吡唑Schiff碱及铜(II)、镍(II)、锌(II)、钴(II) 4个金属配合物. 用元素分析, IR, 1H NMR及单晶解析表征了Schiff碱及金属配合物的结构. 测定了Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌、枯草杆菌和绿脓杆菌的抑菌活性. 生物活性研究表明, Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌和绿脓杆菌都有较好的抑菌效果, 其中铜(II)和锌(II)配合物对金黄色葡萄球菌和大肠杆菌的抑菌活性最好.     

一种新的不对称Schiff碱与稀土配合物合成机理及波谱

采用一种新途径 ,利用反应物前体 2 ,6 二氨基己酸 (赖氨酸 )两端具有不对称结构的—NH2 基 ,成功地合成了一端与水杨醛 ,另一端与邻香草醛缩合形成的新型不对称双Schiff碱 .为与通常不对称Schiff碱区别起见 ,称之为“异双Schiff碱” .提出了这类Schiff碱及配合物的合成方法 ,并以此分别合成了包括钇的 1 2种稀土不对称Schiff碱新配合物 .对它们作了元素分析、摩尔电导、红外光谱 ,特别是1H与13 CNMR等表征 ,并研究和讨论了这类不对称Schiff碱分步缩合反应及其形成机理与稀土离子配位方式 .为合成类似不对称Schiff碱与配合物提供了一种新方法 .     

5-硝基水杨醛缩硫脲及其铜(Ⅱ)、镍(Ⅱ)、锌(Ⅱ)配合物的合成与光热性质

用5-硝基水杨醛与硫脲缩合制备出一种Schiff碱配体,将其分别与Cu(Ⅱ),Zn(Ⅱ)和Ni(Ⅱ)作用合成出了Schiff碱配合物.采用元素分析、红外光谱、紫外光谱、差热热重、摩尔电导率、核磁共振等分析方法对化合物进行表征和测试,并研究了配合物的热力学稳定性及其荧光性质.     

氮杂冠醚取代单Schiff碱过渡金属配合物催化氧化对二甲苯研究

本文将苯并-10-氮杂-15-冠-5或吗啉基取代的单Schiff碱过渡配合物作为催化剂,在常压和120℃条件下,以空气为氧源,研究了对二甲苯催化氧化反应。实验探讨了Schiff碱配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基和反应时间等对对二甲苯催化氧化反应的影响。实验结果表明:Schiff碱配合物中氮杂冠醚的存在能显著缩短反应诱导期,提高催化反应活性和产物选择性;Schiff碱Mn(III)配合物比Schiff碱Co(II)具有更高的催化反应活性;氮杂冠醚Schiff碱Mn(III)配合物对于二甲苯的催化氧化反应转化率大于60%,对甲苯甲酸产物的选择性均高于70%。     

氮杂冠醚取代非对称双Schiff碱配合物催化氧化对二甲苯研究

将一系列苯并-10-氮杂-15-冠-5或吗啉基取代的不对称双Schiff碱配合物作为催化剂,在常压和120℃条件下用于催化氧化对二甲苯研究。探讨了Schiff配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基等对催化氧化对二甲苯反应活性及其氧化产物选择性的影响。实验结果表明:配合物中氮杂冠醚的存在能显著缩短反应诱导期、提高催化活性和选择性;Schiff碱Mn(Ⅲ)配合物比Schiff碱Co(Ⅱ)和Schiff碱Cu(Ⅱ)具有更高的催化活性;氮杂冠醚Schiff碱Mn(Ⅲ)配合物催化氧化二甲苯的转化率和产物选择性分别达75%和90%。     

几个新型呋喃氨基腈衍生物的合成及抗菌活性

用5-甲基-4-乙氧羰基呋喃氨基腈与芳醛反应制得Schiff碱,再采用NaBH4还原Schiff碱,得到3个新型5-甲基-4-乙氧羰基呋喃氨基腈衍生物.利用核磁共振谱(1H NMR)、红外光谱(IR),质谱(EI-MS)表征了产物的结构;并初步测定了产物的抗菌活性.结果表明,目标化合物的抗菌活性一般.     

Schiff碱二价钐配合物[2-OC_6H_4CH═N(2,6-~iPr_2C_6H_3)]_2Sm(THF)_2催化己内酯开环聚合

(取代 )水杨醛缩合的 Schiff碱作为一种辅助配体广泛用于过渡金属有机化学中 ,如 Salen Al可以催化丙交酯、己内酯等环酯的开环聚合 [1]。近来 ,Grubbs等 [2 ]发现 ,(取代 )水杨醛和芳胺缩合的 Schiff碱后过渡金属 Ni配合物 ,在不加助催化剂的条件下 ,作为单组分催化剂 ,对乙烯等α-烯烃的聚合具有很高的催化活性[2 ] 。虽然类似的 Schiff碱稀土配合物也有一些报道 ,但有关其催化聚合反应性能的研究还很少见 [3]。我们选用 Sm I2 为起始原料 ,合成了 Schiff碱二价 Sm配合物 ,并发现这种配合物对己内酯开环聚合有高催化活性 ,生成聚合物…     

氮杂冠醚化双Schiff碱配合物催化羧酸酯水解的研究

将4种氮杂冠醚取代的双Schiff碱钴(H)、锰(m)配合物作为仿水解酶模型催化羧酸酯(PNPP)水解.考察了Schiff碱配合物中氮杂冠醚取代的位置、氮杂冠醚的数目对其仿水解酶性能的影响;探讨了Schiff配合物催化PNPP水解的动力学和机理;提出了配合物催化PNPP水解的动力学模型.结果表明,在25℃条件下随着缓冲溶液pH值的增大,配合物催化PNPP水解速率提高;四种氮杂冠醚取代的双Schiff碱配合物在催化PNPP水解反应中表现出良好的催化活性;氮杂冠醚3-取代的Schiff碱配合物CoL2的催化活性高于5-取代的Schiff碱配合物CoL1,含有2个氮杂冠醚的配合物CoL3的催化活性高于含有1个氮杂冠醚的配合物CoL2.     

抗癌药物的电化学研究Ⅰ.一种Fe(Ⅲ)Schiff碱配合物的基本电化学性质及其与DNA的相互作用

研究了一种自合成的Schiff碱配合物的电化学行为及其与氧和DNA的相互作用.发现此种Schiff碱配合物能与氧发生相互作用而具有吸氧功能,并对氧的电还原有催化作用,同时还发现dsDNA能与此种Schiff碱配合物发生较强的相互作用,特别是Fe(Ⅱ)Schiff碱配合物更易与dsDNA结合.     

Schiff碱镧配合物的合成及其催化烷基异氰酸酯聚合

通过氯化镧与Schiff碱钠盐(NaSalen)的交换反应制备了4种镧的Schiff碱配合物La(HSalen1-4)3,对其中以3,5-二叔丁基水杨醛缩苯胺为配体的配合物La(HSalen2)3进行了X-射线单晶衍射分析,测定其单晶结构为五角双锥构型,七配位的镧金属中心与氮和氧原子相连.将所得的La(HSalen)3...     

Analysis of thermal decomposition products arising from polyvinyl chloride analogs by supersonic jet/multiphoton ionization/mass spectrometry

Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) were thermally decomposed at 200-500 degrees C, and the reaction products measured by supersonic jet/multiphoton ionization/mass spectrometry. No precursor molecules of dioxins, such as chlorobenzene, were observed from PVC, although benzene was produced as one of the major components. On the other hand, a large peak corresponding to chlorobenzene was observed, when CPVC was used as a sample. These results suggest that the release of hydrogen chloride and aromatic ring formation occur efficiently and produce chlorinated aromatic hydrocarbons only when excess chlorine atoms are present in the chain of PVC. This method, which has very high selectivity is preferred for trace analysis of specific compounds such as dioxin precursors in a complex mixture. Isomer-selective analysis, e.g. detection of o-, m-, and p-dichlorobenzenes, is also demonstrated in this study.     

Method to screen aromatic ligands in mixtures for quantitative affinities to target using magnetic separation of bound ligands along with HPLC and UV photometry detection

A new screening method was tested to estimate the affinity of an aromatic ligand in a mixture through competitive binding against an exogenous reference ligand. The target protein was immobilized on magnetic particles and one or several ligand(s) in each reaction mixture were prepared by parallel combinatorial-synthesis without purification. Specifically, the binding of aromatic biotin derivatives to streptavidin immobilized on magnetic particles was used as the model. An approximation equation that works under the condition of binding ratios below 0.1 for the candidate ligand and the reference ligand was developed. It was found that the relative affinity of each biotinylated aromatic candidate ligand in mixtures was consistent with that by using HPLC-MS analyses or by a homogenous method using its purified counterpart. Hence, this new screening method using HPLC-UV is considered to be highly effective.

Bromine formation in solid NaBr/KNO<Subscript>3</Subscript> mixture and assay of this reaction via bromination of activated aromatics

Bromine formation in the mixture of solid NaBr and KNO₃ was observed and the process was studied in different acidified organic solvent–water mixtures by monitoring the bromination of acetanilide and other compounds, containing activated aromatic substituents. This assay is based on fast bromination reaction of these aromatic compounds, as differently from the assay of Br₂, the brominated aromatics can be easily determined by conventional gas chromatography–mass spectrometry (GC–MS) methods. It was found that bromine was generated autocatalytically on the surface of salt crystals and the reaction was characterized by a lag period, the duration of which depended on reaction conditions, and importantly on the type of the organic solvent in the reaction mixture. As the bromine formation could be easily controlled by reaction conditions, it was suggested that the studied reaction might have practical applications as an environmentally friendly and economically feasible bromination method. It was also shown that the bromination of aromatics followed the mechanism of classical electrophilic aromatic substitution reaction.     

微波干法催化芳香醛与绕丹宁及N-苯基绕丹宁的缩合反应

利用微波辐射和固体碱性载体试剂催化绕丹宁及N-苯基绕丹宁和芳香醛的缩合反应合成了14个绕丹宁衍生物并研究了影响反应的因素。     

Microwave Assisted One-pot Synthesis of 2-Amino-4H-chromenes and Spiropyrano[2,3-d]pyrimidine

A convenient and efficient method using microwave assisted one pot synthesis reactions for synthesis of 4H‐benzo[f]chromenes by the reaction of aromatic aldehydes with a mixture of malononitrile and naphthols was examined. The synthesis of spiropyrano[2,3‐d]pyrimidines by the reaction of isatin with malononitrile and barbituric acid and/or thiobarbituric acid was investigated. The versatility of the method was also examined through the reaction of aromatic aldehydes and malononitrile with various reagents.     

An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite

Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.     

Determination of 15 polycyclic aromatic hydrocarbons in aquatic products by solid‐phase extraction and GC–MS

We propose a method for the simultaneous determination of 15 kinds of polycyclic aromatic hydrocarbons in marine samples (muscle) employing gas chromatography with mass spectrometry after saponification with ultrasound‐assisted extraction and solid‐phase extraction. The experimental conditions were optimized by the response surface method. In addition, the effects of different lyes and extractants on polycyclic aromatic hydrocarbons extraction were discussed, and saturated sodium carbonate was first used as the primary saponification reaction and extracted with 10 mL of ethyl acetate and secondly 1 mol/L of sodium hydroxide and 10 mL of n‐hexane were used to achieve better results. The average recovery was 67–112%. Satisfactory data showed that the method has good reproducibility with a relative standard deviation of <13%. The detection limits of polycyclic aromatic hydrocarbons were 0.02–0.13 ng/g. Compared with other methods, this method has the advantages of simple pretreatment, low solvent consumption, maximum polycyclic aromatic hydrocarbons extraction, the fast separation speed, and the high extraction efficiency. It is concluded that this method meets the batch processing requirements of the sample and can also be used to determine polycyclic aromatic hydrocarbons in other high‐fat (fish, shrimp, crab, shellfish) biological samples.     

Unusual transannular cyclization products of sarcophytoxide, a 14-membered marine cembranoid: anomalous stereochemistry of epoxide-ketone rearrangement

[reaction: see text] Treatment of sarcophytoxide with trimethylsilyl trifluoromethanesulfonate afforded an aromatic ketone as an unusual cyclization product. The modified Mosher's method and X-ray analysis performed on the aromatic ketone revealed that it is a 4:1 mixture of 8(R)- and 8(S)-enantiomers. It also suggested that the precursor ketone has 8(R)-configuration, which is contradictory to that expected from the ordinary epoxide-ketone rearrangement.     

Direction of bromination and nitration of deoxypeganine and its hydrochloride using HPTLC. Synthesis of 6-bromo(nitro)-, 6,8-dinitrodeoxyvasicinones, 6-nitro(bromo)-, 6,8-dinitrodeoxypeganines,and 6H(bromo)peganols

The reaction of deoxypeganine (DOP) (1) and its hydrochloride (DOP·HCl) (2) with N-bromosuccinimide and a nitrating mixture was studied. It was found that bromination of DOP occurred at C-4 and the aromatic ring. Nitration of DOP·HCl produced either 6-nitro- or 6,8-dinitro-deoxypeganines and 6-nitrodeoxyvasicinone or their mixture in various ratios depending on the substrate:nitrating mixture ratio. 6Hand 6-Br-deoxypeganines were transformed into the 4-hydroxy derivatives, 6H(Br) peganols or deoxyvasicinones. A method for qualitative and quantitative analysis of the pure compounds and the mixture of reaction products using HPTLC was developed. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 505–509, September-October, 2008. Original article submitted March 26, 2008.     

Synthesis of soluble aromatic polyesteramides by stepwise copolycondensation of bisphenols and aromatic diamines with diphenyl chlorophosphate in pyridine

The reaction promoted by diphenyl chlorophosphate (DPCP) in pyridine was successfully applied to the preparation of soluble aromatic copolyesteramides of high molecular weights directly from aromatic dicarboxylic acids, bisphenols, and a wide range of mol % aromatic diamines. Dropwise addition of a mixture of bisphenols and diamines (more favorably of bisphenols and then diamines) to the mixture of dicarboxylic acids activated by DPCP led the reactions homogeneously even with high mol % of diamines to produce copolymers of good solubility. This improved copolymer solubility was roughly estimated by sequence distribution of polyamide and polyester units in the copolymers, which was studied in a model reaction and in the copolycondensations by simultaneous and stepwise addition of bisphenols and diamines.