N-ethylimidazole Research Articles

酸性离子液体的合成及催化缩醛反应的应用

使用苄基氯，N-乙基咪唑，吡啶等合成了3种新型的离子液体，对其结构进行了表征，并将其应用于催化合成苯甲醛缩醛反应，通过与传统催化剂催化效果相对比，最终确认N-乙基咪唑-N(对磺酸基)苄基-氯化咪唑盐离子液体有良好的催化性能，其催化效率比传统的硫酸铜催化剂高，并进一步对该离子液体的催化条件进行了优化，结果表明，离子液体用量为原料总物质的量的2.8%，反应时间2 h，反应温度125℃时，催化效果最好，产率达到了88.59%，离子液体重复使用4次，催化效能未见明显下降。 Three novel ionic liquids were synthesized using benzyl chloride, N-ethyl imidazole and pyridine as raw materials, the structure of these products were charactered, and these materials were applied to catalytic synthesis of benzaldehyde acetal. Compared with the traditional catalyst, the N-ethyl imidazole-N (p-sulfo) benzalhydantoin-chloride imidazole salt ionic liquids have good catalytic activity. The synthesis reaction of benzaldehyde acetal catalyzed by the acidic ionic liquid was studied. The result shows that the yield of benzaldehyde acetal was 88.59% under the following conditions: Molar percentage of catalyst relative to the reactants 2.8%, reaction temperature 125˚C and reaction time 2 h. The catalytic activity maintains stable even the acidic ionic liquid was used 4 times.

Influence of Ligand Structure on the Hydrolysis and Stability of NAMI Derivatives Containing 2-Methyl imidazole andN-Ethyl imidazole

Two NAMI (new antitumor metastasis inhibitor; trans-[RuCl4(DMSO)(imidazole)]Na•2DMSO) derivatives, trans-[RuCl4(DMSO)(2-MeIm)Na•2DMSO (2-MeIm=2-methyl imidazole, Compd. 1) and trans-[RuCl4(DMSO)(N-EtIm)]Na•2DMSO (N-EtIm=N-ethyl imidazole, Compd. 2) were prepared. Their hydrolytic mechanism-kinetics in pH 7.40/5.00 buffer solution and stability in physiological condition were investigated by UV, cyclic voltammetry (CV) and NMR. Similar to NAMI, both compounds undergo two well separated steps chloro-hydrolysis in pH 7.40 buffer solution; while dimethyl sulfoxide (DMSO) hydrolyze in pH 5.00 acetic buffer solution. The kobs and t1/2 for each reaction were determined. In conclusion, the stability of the complex in acidic solution is much more stable. The stability of the complex formed by introducing ethyl group at N position of imidazole ring would be much better than that of complex formed by introducing methyl group at 2 position of imidazole. The NAMI-A (new antitumuor metastasis inhibitor, A: this is the first of a series; trans-[RuCl4(DMSO)(imidazole)][Himidazole]) derivatives are somewhat more No. 7 梁曜华等: 配体结构对含 2-甲基咪唑及 N-乙基咪唑的 NAMI 衍生物水解及溶液稳定性的影响 865 stable than the relative NAMI derivatives.

Synthesis and biological evaluation of 3-(azolylmethyl)-1H-indoles and 3-(α-azolylbenzyl)-1H-indoles as selective aromatase inhibitors

This present study identifies a number of azolyl-substituted indoles as potent inhibitors of aromatase. In the sub-series of 3-(azolylmethyl)-1H-indoles, four imidazole derivatives and their triazole analogues were tested. Imidazole derivatives 11 and 14 in which the benzyl moiety was substituted by 2-chloro and 4-cyano groups, respectively, were the most active, with IC50 values ranging between 0.054 and 0.050 μM. In the other sub-series, eight 3-(α-azolylbenzyl)-1H-indoles were prepared and tested. Compound 30, the N-ethyl imidazole derivative, proved to be an aromatase inhibitor, showing an IC50 value of 0.052 μM. All target compounds were further evaluated against 17α-hydroxylase/C17,20-lyase to determine their selectivity profile.

Gold(III) complexes with imidazole, benzoxazole, purine and pyrimidine derivatives

The synthesis and characterization of AuIII complexes with several heterocyclic ligands are reported. The compounds have general formula [AuX3(L)], where L =N-methylimidazole (N-MeIz),N-ethylimidazole (N-EtIz),N-propylimidazole (N-PrIz), benzoxazole (BO), 2-methylbenzoxazole (2-MeBO), 2,5-dimethylbenzoxazole (2,5-diMeBO), 2-amino-pyrimidine (2-APm), 4(6) -hydroxy-pyrimidine [4(6)-hydrPm] or hypoxanthine (Hypox) and X = Cl or Br. Elemental analysis, conductivity measurements and spectral studies were used for the characterization of the complexes. A square-planar geometry withN-bonded heterocyclic ligands is suggested.

Gold(I) complexes of azoles

(Dimethyl sulphide)AuCl reacts with azoles to give adducts [LAuX]2 [L = N-methylimidazole (N-MeIm), N-ethylimidazole (N-EtIm), N-propylimidazole (N-PrIm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-diMeBO); X = Cl or Br] which were characterized analytically and spectroscopically, including 1H-n.m.r. I.r. and Raman studies showed that the compounds were binuclear with bridging halogen atoms. A nitrogen-containing ligand was coordinated to nitrogen N(3) atom of the azole ring in monodentate fashion.

Platinum(IV) complexes with purine or pyrimidine and imidazole derivatives

PtIV mixed chloride complexes with purine or pyrimidine and imidazole derivatives have been prepared and characterized. The compounds have general formula [Pt(L1)(L2)Cl4], where L1=purine (pur) or pyrimidine (pyr) and L2=N-methylimidazole (N-MeIm),N-ethylimidazole (N-EtIm) orN-propylimidazole (N-PropIm), except for the complex [Pt(pur)(pyr)Cl4]. The nitrogen bases act as monodentate ligands coordinatedvia nitrogen. The far i.r. and electronic reflectance spectra indicate a hexacoordinate geometry. The complexes competitively inhibit lentil amine oxidase, with highest inhibition for [Pt(pur)(N-EtIm)Cl4].

Platinum(II) and palladium(II) chlorides complexes with purine, pyrimidine,N-ethylimidazole andN-propylimidazole

Platinum(II) and palladium(II) chloride complexes with purine, pyrimidine (pyrimid),N-ethylimidazole(N-EtIm) andN-propylimidazole(N-PropIm) ligands have been prepared and characterized by analysis and spectroscopic methods. The compounds have general formula M(L1)(L2)Cl2 where M=PtII, PdII; L1=purine or pyrimid, L2=N-EtIm orN-PropIm, except the complexes Pt(purine)(pyrimid)Cl2 and [Pd(purine)(pyrimid)2Cl]Cl and [Pt(purine)2 (N-propIm)Cl]Cl·2H2O.

Spectroscopic, biological, and antitumor studies on N-ethyl- and N-propylimidazole platinum(II) complexes

Platinum(II) halide complexes with N-ethylimidazole ( N-EtIm) and N-propylimidazole ( N-Proplm) of the Pt(L) 2X 2 and Pt(L) 4X 2 types (X = Cl, Br, I) were prepared and characterized by far infrared spectra, electronic spectra, and conductivity measurements. The inhibitorial activity of some complexes on the Ca,Mg-dependent ATPase and the antitumor studies of the Pt(L) 4Cl 2 derivatives have been investigated. Pt complexes are not inhibitory active in comparison to the same Pd complexes (if c = 10 −4 M). The LD 50 in physiological solution for [Pt( N-EtIm) 4]Cl 2 · 2H 2O and [Pt( N-PropIm) 4]Cl 2 are higher enough with respect to the cis platinum.

A biological study on the palladium(II) and platinum(II) complexes with heterocyclic ligands

In recent work [1] we studied the inhibitory activity of some ML 2X 2 complexes (M = Pd(II), Pt(II), L = isox and its derivatives, X = Cl, Br) on the Ca, Mg dependent ATP-ase. We have now examined the inhibitory effect of the palladium(II) and platinum(II) complexes with benzoxazole (BO) and 2-methylbenzoxazole (MeBO), the palladium compounds with N-ethylimidazole (N-EtIm), N-propylimidazole (N-PropIM) and the palladium(II) oxalato complexes with heterocyclic ligands. The extraction method of the sarcoplasmatic reticulum (SR) containing Ca, Mg dependent ATP-ase and the inhibitory activity of the complexes towards the ferment and the SH groups determinations by amperometric titrations were published previously [2, 3]. Regarding the benzoxazole and 2-methylbenzoxazole complexes [4], the inhibitory activity in aqueous solution with respect to the Ca, Mg dependent ATP-ase of the palladium(II) is greater than that of the palladium(II) complexes. The chloride derivatives show a greater effect with respect to the bromide for the high lability of the former in comparison with the latter ion. The introduction of a methyl group in position two of the BO ring does not seem to modify the inhibitory effect of the Pd(II) compounds. As regards the N-EtIm and N-PropIm palladium(II) complexes [4] the inhibitory effect in salt aqueous solution of the N-PropIm compounds is higher than the N-EtIm complexes. This fact can be explained by the length of the N-PropIm chain which renders the complex soluble in the enzyme lipidic part. The [Pd(N-PropIm) 2Cl 2] has an activity almost double that of [Pd(N-PropIm) 4]Cl 2, because in the latter case it is difficult to substitute the ligands with water molecules and successively with thiolic groups. The [Pd(L) 4X 4 derivatives have an activity which increase in the sequence I > Br > Cl. These results are compared with the activity of the platinum(II) complexes in aqueous solution [5]. Because the oxalato complexes are soluble in water and very important in biological systems, we have studied the monomeric, water-soluble [Pd(ox)(L) 2] (where L = imidazole and aminoisoxazole derivatives or L 2 = en) and the dimeric, almost insoluble in water, Pd(ox)(L) (where L = isox, 3,5diMeisox, BO and its methyl derivatives) [6]. The inhibitory activity of the Pd(ox)(L) 2 decreases in order N-PropIm > N-EtIm > N-MeIm because the greater length of the ligand chain renders the respective complex more soluble in the ATP-ase lipidic part. The Pd(ox)(en) has no inhibitory effect for the presence of strong bonds of the chelating en. In the Pd(ox)(L) derivatives this effect is generally higher than in Pd(ox)(L) 2, because the L bridging ligand is easily substituted with water molecules and with thiol groups of the enzyme.

Spectroscopic and biological studies on palladium(II) complexes with N-ethyl and N-propylimidazole

Abstract Palladium(II) halide complexes with N-ethylimidazole (N-EtIm) and N- propylimidazole (N-PropIm) with general formulae Pd(L) 2 X 2 and Pd(L) 4 X 2 (X = Cl, Br, I) were prepared and characterized by spectroscopic methods and conductivity measurements. These complexes are diamagnetic and have square planar stereochemistry. The Pd(L 2 )X 2 derivatives, are non-conductors, and have trans -structures except for the cis -Pd(N-EtIm) 2 Br 2 . The biological activity of water soluble Pd(II) compounds is also reported.

Magnetic measurements on dimeric and tetrameric fluoro-bridged cobalt and manganese compounds

Measurements of the magnetic susceptibility (2 K< T<100 K), high-field magnetization ( B max≈30 T) and specific heat (0.1 K T<100 K) are reported on the dimetric compounds [Co F L 3] 2(BF 4) 2, with L=3,5-dimethyl-pyrazole (DMPz); 3,4,5-trimethylpyrazole (TMPz); and 4-ethyl-3,5-dimethyl-pyrazole (EDMPz); as well as on the tetrameric compounds [Co F L 3] 4(BF 4) 4 and [Mn F L 3] 4(BF 4) 4 with L=N-ethylimidazole (NEtIz) and lastly on [Co F L 3] 4(BF 4) 4 with L=N-propylimidazole. In these materials the 3 d-metal ions are magnetically coupled via the fluor ligands with M-F-M-bond angles of about 100° to form dimeric or tetrameric antiferromagnetic clusters. In the dimeric and tetrameric compounds the metal ions are in 5 and in 6 coordination, respectively. The analysis of the experiments in terms of magnetic cluster models yields an estimate of the exchange constants in the materials. For [Co F (DMPz) 3] 2(BF 4) 2, [Co F (EDMPz) 3] 2(BF 4) 2 and [Co F (TMPz) 3] 2(BF 4) 2 we obtain J/K⋍−1 K , −4± 1 K, and −4±1 K, respectively. For [Co F (NEtIz) 3] 4(BF 4) 4 and [Mn F (NEtIz) 3] 4(BF 4) 4 the v values are J/K⋍−10 K and −1.2±0.5 K. Comparing these results with typical values for 180° fluoro-bridged exchange paths, namely 70–100 K for cobalt salts and 3–4 K for manganese compounds, one observes a drastic reduction in the strength of the antiferromagnetic exchange constant. This reduction is predicted by recent theoretical models for the superexchange interaction.

Cationic and alkynyl complexes of the trans(mesityl)bis(phenyldimethylphosphine)nickel(II) moiety

A cationic complex, trans-[(mesityl)Ni(PPhMe 2) 2(NCMe)]ClO 4 (IIa), has been prepared rom trans-(mesityl)Ni(PPhMe 2) 2Br and silver perchlorate in acetone/acetonitrile. IIa reacts with several neutral ligands to give trans-[(mesityl)Ni(PPhMe 2) 2L]ClO 4 (L = 2-pic, 3-pic, 3,4-lut, 2,5-lut, methyl isonicotinate, N-ethyl imidazole, PPhMe 2, P(Ome) 3), with halide anions to give trans-(mesityl)Ni(PPhMe 2) 2X (X = Cl, NNN), and with terminal alkynes in the presence of triethylamine to give trans-(mesityl)Ni(PPhMe 2) 2CCR (R = H, Me, CH 2CH 2Oh, Ph, C 6H 4OMe- p). Some related alkynyl complexes trans-CCl 2CClNi(PPhMe 2) 2CCR (R = H, Me, Ph, C 6H 4OMe- p) and trans-{( o-MeO) 2C 6H 3}Ni(PPhMe 2) 2CCr (R = H, Ph) also have been prepared from the corresponding trans-R′Ni(PPhMe 2) 2Cl, silver perchlorate and HCCR in acetonitrile-triethylamine. trans-(Mesityl)Ni(PPhMe 2) 2CCH reacts with methanol in the presence of perchloric acid to give a cationic carbne complex, trans-[(mesityl)Ni(PPhMe 2) 2{C(OMe)Me}]ClO 4.

Electron spin resonance studies on Cu(N-Ethyl imidazole) 4(ClO 4) 2 and Cu(N-Propyl imidazole) 4(ClO 4) 2

Electron spin resonance (ESR) studies have been made on the undiluted Cu(N-ethyl imidazole) 4(ClO 4) 2 and Cu(N-propyl imidazole) 4(ClO 4) 2 complexes in their polycrystalline forms at 295 and 77 K. The spectra are characterized by the resolution of cupric ion hyperfine splittings which is not usual. The g- and A-values are typical of square planar symmetry with monodentate ligands. Surprisingly the nitrogen hyperfine splitting could not be resolved either at 295 or at 77 K. The widths of various components in the spectra showed little variation from room temperature to the temperature of liquid nitrogen leading to the conclusion that the contribution to linewidth from spin-lattice relaxation is negligible and a sufficient amount of spin-spin interaction is still present to smear the nitrogen hyperfine splittings. These couid, however, be resolved by effecting a dilution of the copper complexes with 5 per cent of zinc perchlorate. The MO coefficients have been evaluated using ESR and optical absorption data.

Outer‐sphere electron‐transfer reactions of co(III)–polymer complexes in relation to its polymer effects

AbstractThe outer‐sphere electron‐transfer reactions between [Co(III)(NH3)5L] (CIO4)3 [L = polyethyleneimine (PEI), L = NH3(Amm)] or cis‐[Co(III)(en)2L′Cl]Cl2 [L′ = poly‐N‐vinyl‐2‐methylimidazole(PVI), poly‐4‐vinylpyridine (PVP), N‐ethylimidazole (NEI), pyridine (Py)] and various Fe(II) were studied. In the reaction with Fe(II)‐(phen)32+, the reactivity of Co(III)–PEI was smaller than that of Co(III)–Amm due to the larger electrostatic repulsion. On the other hand, the reactivity of Co(III)–PEI was larger by a factor of 80 in the reaction with Fe(II)(H2O)62+. From the results of rapid‐scanning spectroscopy, the higher reactivity of Co(III)–PEI is caused by the coordination of free ethyleneimine residues in the Co(III)–PEI to Fe(II)–ion. Further more, the hydrophobic interaction between heteroaromatic polymer ligands and Fe(II)‐(phen)32+ brought about the higher reactivities of Co(III)–PVI and Co(III)–PVP. Three interactions caused by the essential properties of polymers are discussed in relation to conformational changes.

Influence of conformational changes of co(III)–poly‐N‐vinyl‐2‐methylimidazole complexes on electron‐transfer reactions of the complexes

AbstractIn order to study the effect of conformational changes in electron‐transfer reactions of Co(III)–polymer complexes, cis‐[Co(III)(en)2LCl]Cl2, where the ligand L is PVI(poly‐N‐vinyl‐2‐methylimidazole) or NEI (N‐ethylimidazole), was prepared. Electrontransfer reactions with ferrous sulfate or FeEDTA2− were examined mainly with respect to the effects of the degree of coordination, ionic strength, composition of reaction solvent, in relation to the conformational changes. In the reduction by FeEDTA2−, an increase in the degree of coordination of Co(III)–PVI brought about an extreme increase in its reactivity, while it was almost unity in the reduction by ferrous sulfate. With an increase in the ionic strength, the reactivity decreased due to the electrostatic shielding in the reduction by FeEDTA2−. It was noticed that the reaction of Co(III)–PVI was much more enthalpically disadvantageous due to the shrinkage of the polymer chain than that of Co(III)–NEI, when neutral salts were added. In an aqueous alcoholic solvent, an increase in the alcohol concentration accelerated the reaction with FeEDTA2−, and especially in the reaction of Co(III)‐PVI, the maximum and minimum points of the reactivity were observed. On increasing the reaction temperature, the maximum and minimum points shifted to lower alcohol concentration. These phenomena are discussed in regard to the conformational changes of Co(III)–PVI.