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1.
Cyclometalated 2-phenylpyridine complexes [Ru II( o-C 6H 4-2-py)(LL) 2]PF 6, LL = 2,2′-bipyridine (1) and 1,10-phenanthroline (2) were resolved into Δ and Λ enantiomers using column chromatography on SP Sephadex C-25 in the presence of (+)-2,3-dibenzoyl- D-tartrate. The absolute configuration of enantiomers was established using circular dichroism spectroscopy. The rate constants ket for the electron transfer from reduced glucose oxidase (GO from Aspergillus niger) and PQQ-dependent glucose dehydrogenase (GDH) at the generated Ru III species were measured by cyclic voltammetry and UV–vis spectroscopy. The electron transfer shows enantioselectivity. In the case of GO, the bell-shaped pH profile for the ratio kΛ/ kΔ has a maximum at pH 7 ( kΛ/ kΔ equals 3.4 and 3.9 for 1 and 2, respectively), but its inversion is observed at pH around 5 and 9. The kΛ/ kΔ ratio equals 2.0 for 2 and GDH at pH 7. The results of theoretical modeling of biological electron transfer for GO using functional docking Monte-Carlo simulations are presented and analyzed together with the experimental observations. 相似文献
2.
Four ergosterol derivatives (1–4) have been isolated for the first time from the fruiting bodies of a basidiomycete fungus, Lactarius hatsudake, through activity-guided fractionation. Their structures were determined, using spectroscopic analysis, as: (22 E,24 R)-ergosta-5,7,22-dien-3 β-ol (ergosterol, 1); 5 ,8 -epidioxy-(22 E,24 R)-ergosta-6,22-dien-3 β-ol (ergosterol peroxide, 2); 5 ,8 -epidioxy-(24 S)-ergosta-6-en-3 β-ol (3); and (22 E,24 R)-ergosta-7,22-dien-3 β,5 ,6 β-triol (cerevisterol, 4). Compounds 2 and 3 showed selective inhibitory activity against Crotalus adamenteus venom phospholipase A 2 (PLA 2) enzyme, but not against Apis mellifcra bee venom PLA 2. The antiphospholipase A 2 activity of compounds 2 and 3 are reported here for the first time. 相似文献
3.
The Dmt-Tic pharmacophore exhibits potent δ-opioid receptor antagonism. Analogues with substitutions in the second pharmacophore with (1, 1′) or without a COOH function (2–9) were synthesized: several had high δ affinity (1′, 2, 7, and 9), but exhibited low to non-selectivity toward μ receptors similar to H-Dmt-Tic-amide and H-Dmt-Tic-ol. Functional bioactivity indicated high δ antagonism (p A2 7.4–7.9) (1′, 2, and 9) and modest μ agonism, pEC 50 (6.1–6.3) (1′, 2, 8, and 9), but with Emax values analogous to dermorphin. These Dmt-Tic analogues with mixed δ antagonist/μ agonist properties would appear to be better candidates as analgesics than pure μ agonists. 相似文献
4.
The dicarbonylation reaction of E-β-deuteriostyrene to syndiotactic poly(1-oxo-2-phenyltrimethylene) as well as to dimethyl-2-phenylbutanedioate and dimethyl-2,5-diphenyl-4-oxoheptanedioate using Pd(CF 3COO) 2/2,2′-bipyridine as the catalyst precursor in the presence of 1,4-benzoquinone in methanol takes place stereospecifically in a syn-fashion with complete retention of the label. The same result was found for the dicarbonylation to dimethyl 2-phenylbutanedioate catalyzed by [Pd(CF 3COO) 2(Diop)]. In the absence of the oxidant the latter catalytic system produces methyl 2- and 3-phenylpropionates for which some scrambling of deuterium is observed when using either -deuteriostyrene or CH 3OD as the labeled substrate. [Pd(CH 3CN) 4][BF 4] 2 modified with different ligands catalyses the formation of E-1,5-diphenylpent-1-en-3-one or of E-1,4-diphenylpent-1-en-3-one in tetrahydrofuran as the solvent. The label distribution using E-β-deuteriostyrene as the substrate (or styrene in the presence of dideuterium) suggests that in the synthesis of ketones catalyzed by [Pd( p-CH 3C 6H 4SO 3) 2(Dppp)]·2H 2O the regioselectivity of the first inserted olefin unit does not determine the ketone regioisomer; rather which regioisomeric product preferentially forms depends on the rate of carbon monoxide insertion in either the branched or linear metal-hydrocarbyl intermediate. β-Hydrogen elimination is very rapid both after the first and the second olefin insertion. 相似文献
5.
Two novel dinuclear palladium(II) complexes, {[Pd(en)Cl] 2(bpse)}(NO 3) 2 (1) and {[Pd(en)Cl] 2 (bpsu)}(NO 3) 2 (2), (where en is ethylenediamine; bpse is bis(3-methyl-4-pyridyl) selenide; bpsu is bis(3-methyl-4-pyridyl) sulfide) have been synthesized. The complexes have been characterized by elemental analysis, IR, 1H NMR, and 13C NMR. They have been assayed for antitumor activity in vitro against the mice leukemia L1210 and the human coloadenocarcinoma HCT8 cell lines. The results show that compound 1 has a lower I.D. 50 value against the two cancer cell lines as compared to compound 2; the compounds also shows a lower I.D. 50 value than cisplatin against the HCT8 cell line, but a higher I.D. 50 value than cisplatin against the L1210 cell line. Binding studies indicate that compound 1 possibly interacts with DNA by a nonintercalative mode. Kinetics of binding of the two compounds to DNA are firstly studied using ethidium bromide as a fluorescence probe with stopped-flow spectrophotometer under pseudo-first-order condition. The stronger binding of two steps in the process of the compounds interacting with DNA are observed, and the kobs and Ea of binding of the two steps (where kobs is the observed pseudo-first-order rate constant, Ea is the observed energy of activation) are obtained. 相似文献
6.
Employing high temperature quenched molecular dynamics (QMD) simulations the conformational energy space of an immunostimulating tetrapeptide rigin: H-Gly 341-Gln-Pro-Arg 344-OH, is explored. Using distance dependent dielectric (= rij) 31 different low energy starting structures with identical sequence were computed for their conformational preferences. According to the hypothesis of O'Connors et al. [ J. Med. Chem. 35 (1992), 2870], 83 low-energy conformers resulted from unrestrained molecular dynamics (MD) simulations, could be classified into two energy minimized families: A and B, comprised of 64 (Pro C γ- endo orientation) and 19 (Pro C γ- exo orientation) structures, respectively. An examination of these families revealed the existence of a remarkably similar folded backbone conformation: torsion angles being φ i+1 ≈−65°, ψ i+1 ≈−65°, φ i+2 ≈−65°, ψ i+2 ≈−60°, characterizing a distorted type III β-turn structure across the central Gln-Pro segment. The folded conformation of rigin is devoid of a classical 1 ← 4 intra-molecular hydrogen bond nevertheless, the conformation is stabilized by an effective ‘ salt-bridge’, i.e., Gly H 3N +… C OO − Arg interaction. Surprisingly, in both the families the unusual folded side-chain dispositions of the Gln residue favor the formation of a unique intra-residue ‘main-chain to side-chain’ H-bond, i.e., N –H…N ε interaction, encompassing a seven-membered ring motif. The conformational attributes may be valuable in de novo construction of structure-based drug candidates having sufficient stimulating activity. 相似文献
7.
The lipophilic triphenylmethylphosphonium cation (TPMP +) has been employed to measure ΔΨ m, the electrical potential across the inner membrane of the mitochondria of intact hepatocytes. The present studies have examined the validity of this technique in hepatocytes exposed to graded concentrations of inhibitors of mitochondrial energy transduction. Under these conditions, TPMP + uptake allows a reliable measure of ΔΨ m in intracellular mitochondria, provided that the ratio [TPMP +] i/[TPMP +] e is greater than 50:1 and that at the end of the incubation more than 80% of the hepatocytes exclude Trypan blue. Hepatocytes, staining with Trypan blue, incubated in the presence of Ca 2+, do not concentrate TPMP +. The relationships between ΔΨ m and two other indicators of cellular energy state, Δ GPc and Eh, or between ΔΨ m and J0, were examined in hepatocytes from fasted rats by titration with graded concentrations of inhibitors of mitochondrial energy transduction. Linear relationships were generally observed between ΔΨ m and Δ GPc, Eh or J0 over the ΔΨ m range of 120−160 mV, except in the presence of carboxyatractyloside or oligomycin, where ΔΨ m remained constant. Both the magnitude and the direction of the slope of the observed relationships depended upon the nature of the inhibitor. Hepatocytes from fasted rats synthesized glucose from lactate or fructose, and urea from ammonia, at rates which were generally linear functions of the magnitude of ΔΨ m, except in the presence of oligomycin or carboxyatractyloside. Linear relationships were also observed between ΔΨ m and the rate of formation of lactate in cells incubated with fructose and in hepatocytes from fed rats. The linear property of these force-flow relationships is taken as evidence for the operation of thermodynamic regulatory mechanisms within hepatocytes. 相似文献
8.
1. In membranes prepared from dark grown cells of Rhodopseudomonas capsulata, five cytochromes of b type ( E′ 0 at pH 7.0 +413±5, +270±5, +148±5, +56±5 and −32±5 mV) can be detected by redox titrations at different pH values. The midpoint potentials of only three of these cytochromes ( b148, b56, and b−32) vary as a function of pH with a slope of 30 mV per pH unit. 2. In the presence of a Co/N2 mixture, the apparent E′0 of cytochrome b270 shifts markedly towards higher potentials (+355 mV); a similar but less pronounced shift is apparent also for cytochrome b150. The effect of CO on the midpoint potential of cytochrome b270 is absent in the respiration deficient mutant M6 which possesses a specific lesion in the CO-sensitive segment of the branched respiratory chain present in the wild type strain. 3. Preparations of spheroplasts with lysozyme digestion lead to the release of a large amount of cytochrome c2 and of virtually all cytochrome cc′. These preparations show a respiratory chain impaired in the electron pathway sensitive to low KCN concentration, in agreement with the proposed role of cytochrome c2 in this branch; on the contrary, the activity of the CO-sensitive branch remains unaffected, indicating that neither cytochrome c2 nor the CO-binding cytochrome cc′ are involved in this pathway. 4. Membranes prepared from spheroplasts still possess a CO-binding pigment characterized by maxima at 420.5, 543 and 574 nm and minima at 431, 560 nm in CO-difference spectra and with an band at 562.5 nm in reduced minus oxidized difference spectra. This membrane-bound cytochrome, which is coincident with cytochrome b270, can be classified as a typical cytochrome “o” and considered the alternative CO-sensitive oxidase. 相似文献
9.
Disc electrophoretically homogeneous spinach-chloroplast cytochrome b6 was found to be a lipoprotein whose redox potential was essentially unchanged during isolation. These results further support the hypothesis of Triton X-100/4 M urea, pH 8, as a useful extracting medium for membrane lipoproteins. Cytochrome b6 was found to have a heme equivalent dry weight of 1 mol of heme per 60 000 g. Of this, 20 000 g was lipid-extractable. The molecular weight was 60 000 with a partial specific volume of 0.84 ml/g. The protein portion of the molecule (40 000) consisted of 1 polypeptide chain of 20 000 daltons, 1 of 9600 daltons and 2 of 6600 daltons. A simple lipid composition (relative to the original membrane) was found consisting of 7 mol of chlorophyll a and 6 mol of cardiolipin per mol of cytochrome; these two lipids thus account for about 75–80% of the lipid content. An unidentified minor neutral lipid and minor polar lipid were also detected. At pH 7.0 in the presence of 0.5% Triton X–100, E′0 was −0.080 V, and in the absence of Triton X–100, E′0 was −0.120 V. At pH 8 in 0.5% Triton X–100, E′0 was −0.084 V, thus indicating that the redox potential is independent of pH in the region 7–8. The redox reaction proceeded via a one-electron-transfer. 相似文献
10.
The phosphinoalkenes Ph 2P(CH 2) nCH=CH 2 ( n= 1, 2, 3) and phosphinoalkynes Ph 2P(CH 2) n C≡CR (R = H, N = 2, 3; R = CH 3, N = 1) have been prepared and reacted with the dirhodium complex (η−C 5H 5) 2Rh 2(μ−CO) (μ−η 2−CF 3C 2CF 3). Six new complexes of the type (ν−C 5H 5) 2(Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3)L, where L is a P-coordinated phosphinoalkene, or phosphinoalkyne have been isolated and fully characterized; the carbonyl and phosphine ligands are predominantly trans on the Rh---Rh bond, but there is spectroscopic evidence that a small amount of the cis-isomer is formed also. Treatment of the dirhodium-phosphinoalkene complexes with (η−CH 3C 5H 4)Mn(CO) 2thf resulted in coordination of the manganese to the alkene function. The Rh 2---Mn complex [(η−C 5H 5) 2Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3) {Ph 2P(CH 2) 3CH=CH 2} (η−CH 3C 5H 4)Mn(CO) 2] was fully characterized. Simi treatment of the dirhodium-phosphinoalkyne complexes with Co 2(CO) 8 resulted in the coordination of Co 2(CO) 6 to the alkyne function. The Rh 2---Co 2 complex [(η−C 5H 5) 2Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3) {Ph 2PCH 2C≡CCH 3}Co 2(CO) 2], C 37H 25Co 2F 6O 7PRh 2, was fully characteriz spectroscopically, and the molecular structure of this complex was determined by a single crystal X-ray diffraction study. It is triclinic, space group
( Ci1, No. 2) with a = 18.454(6), B = 11.418(3), C = 10.124(3) Å, = 112.16(2), β = 102.34(3), γ = 91.62(3)°, Z = 2. Conventional R on | F| was 0.052 fo observed ( I > 3σ( I)) reflections. The Rh 2 and Co 2 parts of the molecule are distinct, the carbonyl and phosphine are mutually trans on the Rh---Rh bond, and the orientations of the alkynes are parallel for Rh 2 and perpendicular for Co 2. Attempts to induce Rh 2Co 2 cluster formation were unsuccessful. 相似文献
11.
A series of ( E)-1-phenylbut-1-en-3-ones, based on the naturally occurring ( E)-1-(4′-hydroxyphenyl)but-1-en-3-one [IC 50 (K562) 60 μM], was synthesised and screened for cytotoxic activity against the K562 human leukaemia cell line. ( E)-1-(Pentafluorophenyl)but-1-en-3-one [IC 50 (K562) 1.8 μM] was found to be over 30-fold more active than 1. 相似文献
12.
In this paper are discussed a few theoretical aspects of the transfer, trapping, loss and annihilation of excitations as they occur in a photosynthetic system after a picosecond light pulse. A random-walk model is introduced to describe the dynamical behavior of the excitations in a domain and is used to calculate the parameter that determines the shape of the total fluorescence yield vs. pulse intensity curve in the case in which the reaction centers are all in the closed state (Paillotin, G., Swenberg, C.E., Breton, J. and Geacintov, N.E. (1979) Biophys. J. 25, 513–533). It is shown that this parameter depends critically on the number, λ, of connected photosynthetic units in a domain. A master equation is postulated to describe the decay of the excitations in the case where the transition of the reaction center from the open to the closed state, induced by the capture of an excitation, is included. The trapping and loss of excitation in a mixture of open and closed reaction centers, generated in the course of the transfer process, is assumed to be described by an equation that is the equivalent for a single domain of the Vredenberg-Duysens relation (Vredenberg, W.J. and Duysens, L.N.M. (1963) Nature 197, 355–357). The master equation is used to find the total probability of loss per excitation, Uλ( z), and the total fraction of reaction centers closed, Vλ( z), as a function of the average number of excitations z created in a domain when the reaction centers are all in the open state before the pulse. It is shown that, for most photosynthetic systems, an increase of Uλ( z) with z can occur only if λ 3. It is further concluded that the combined measurement of Uλ( z) and Vλ( z) can give detailed information about λ and the parameters involved in the transfer process. 相似文献
13.
The mixture of isomers of silylated cyclopentadiene derivative C 5H 5CH 2CH 2Si(OMe) 3 (1) has been used for the syntheses of the mononuclear Rh(I) complexes [η 5-C 5H 4(CH 2) 2Si(OMe) 3]Rh(CO) 2 (3). [η 5-C 5H 4(CH 2) 2Si(OMe) 3]Rh(COD) (4) and [η 5-C 5H 4(CH 2) 2Si(OMe) 3]Rh(CO)(PPh 3) (5). Upon entrapment of 3–5 in silica sol-gel matrices, air stable, leach-proof and recyclable catalysts 6–8 resulted. Their catalytic activities in some hydrogenation processes were compared with those of the non-immobilized complexes 3–5, as well as with those of homogeneous and heterogenized non-silylated analogs, 9–14. 相似文献
14.
The shear piezoelectricity was observed in oriented films of poly-β-hydroxybutyrate (PHB) and copolymers of β-hydroxybutyrate (HB) and β-hydroxyvalerate (HV). The piezoelectric stress constant 3 14 = e′ 14 − ie″ 14 (polarization/strain), the piezoelectric strain constant d14 = d′ 14 − id″ 14 (polarization/stress), the elastic constant c = c′ + ic″ and the dielectric constant = ′ − i″ were determined at a frequency of 10 Hz over a temperature range from −150° to +150°C. Piezoelectric relaxations as well as elastic and dielectric relaxations were clearly observed at the glass transition temperature of about 15°C. In order to evaluate the piezoelectric constants ( e2 and d2) for the piezoelectric phase which consists of the crystalline region and the oriented non-crystalline region, a spherical dispersion two phase model was utilized. Assuming the appropriate fixed values for the elastic and dielectric constants in the piezoelectric phase, d2 and d2 were calculated as a function of temperature. For a PHB and a copolymer (17 HV/83 HB), e2 and d2 showed relaxations, leading to a conclusion that the instantaneous piezoelectric constant in the crystalline phase is constant independent of temperature but the piezoelectric constant in the oriented non-crystalline phase is relaxational and has the opposite sign. For a copolymer (25 HV/75 HB) and a chloroform treated copolymer (17 HV/83 HB), e2 and d2 were constant independent of temperature, indicating that the oriented non-crystalline phase has disappeared owing to the increased molecular flexibility due to copolymerization or annealing in chloroform vapour. 相似文献
15.
The initial rate and enantioselectivity of enzymatic asymmetric hydrolysis of amino acid esters were examined in methylimidazolium-based ionic liquids with anions including tetrafluoroborate, chloride, bromide and bisulfate and in typical organic solvents. Papain displayed much higher enantioselectivity but lower activity in phosphate buffer solution of 1-butyl-3-methylimidazolium tetrafluoroborate BMIM·BF 4 than in other media tested (i.e. E=100, V 0=0.21 mM min -1 in BMIM·BF 4, E=2, V 0=0.43 mM min -1 in phosphate buffer, E=14-92, V 0=0.22-0.25 mM min -1 in organic solvents for D,L-phenylglycine methyl ester). The influence of BMIM·BF 4 on enzyme activity and enantioselectivity also varied with the substrate and the enzyme used. All of the enzymes assayed showed no activity or low enantioselectivity in the ILs with anions including chloride, bromide and bisulfate. 相似文献
16.
Four pre-selected indigenous yeast strains belonging to Candida guilliermondii (V 2 and V 5), Candida pulcherrima (V 6) and Kloeckera apiculata (V 9), were used as β-glucosidase (βGL) and β-xylosidase (βXL) sources. The optimization of yeast culture conditions was carried out and the effects of oenological parameters on β-glycosidase activities were evaluated. C. guilliermondii V 2 and C. pulcherrima V 6 strains were selected. These strains showed intracellular ( C. pulcherrima V 6) and parietal ( C. guilliermondii V 2) constitutive βGL and βXL. The enzymatic activities were active at pH, glucose, ethanol and SO 2 concentrations usually found in winemaking and they were able to release monoterpenols and alcohols from grape juice glycoside extracts. Additionally, these yeast strains were not able to produce volatile acidity and off flavour. Regional ecological relevance of these species was also discussed. Our results evidence that the selected C. guilliermondii V 2 and C. pulcherrima V 6 strains have interesting oenological characteristics and allow us to think in their potential application in winemaking. 相似文献
17.
The γ subunits of voltage-dependent calcium channels influence calcium current properties and may be involved in other physiological functions. Five distinct γ subunits have been described from human and/or mouse. The first identified member of this group of proteins, γ 1, is a component of the L-type calcium channel expressed in skeletal muscle. A second member, γ 2, identified from the stargazer mouse regulates the targeting of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors to the postsynaptic membrane. We report here the identification of three novel γ subunits from rat and mouse as well as the unidentified rat, mouse and human orthologs of the previously described subunits. Phylogenetic analysis of the 24 mammalian γ subunits suggests the following relationship ((((γ 2, γ 3), (γ 4, γ 8)), (γ 5, γ 7)), (γ 1, γ 6)) that indicates that they evolved from a common ancestral γ subunit via gene duplication. Our analysis reveals that the novel γ subunit γ 6 most closely resembles γ 1 and shares with it the lack of a PSD-95/DLG/ZO-1 (PDZ)-binding motif that is characteristic of most other γ subunits. Rat γ subunit mRNAs are expressed in multiple tissues including brain, heart, lung, and testis. The expression of γ 1 mRNA and the long isoform of γ 6 mRNA is most robust in skeletal muscle, while γ 6 is also highly expressed in cardiac muscle. Based on our analysis of the molecular evolution, primary structure, and tissue distribution of the γ subunits, we propose that γ 1 and γ 6 may share common physiological functions distinct from the other homologous γ subunits. 相似文献
18.
Chronic ethanol treatment is known to alter gene expression and function of γ-aminobutyric acid type-A (GABA A) receptors. Here we focus on the β 2 subunit which is widely expressed in the mammalian brain, and plays a key role in the GABA binding site. Previous studies using rodent models of ethanol dependence show either increased or no change of β 2 subunit mRNA and peptide content following chronic ethanol administration. In humans, polymorphism at the β 2 subunit is associated with ethanol dependence in some, but not all, populations. In the present study we measured mRNA content in the cerebellum and cerebral cortex using ethanol-naive and ethanol-dependent DBA/2J and C57BL/6J mice. The DBA/2J strain displays severe ethanol withdrawal severity, while the C57BL/6J strain shows milder withdrawal reactions. RNase protection analysis demonstrated that the DBA/2J strain is more sensitive to ethanol-induced increases in β 2 subunit mRNA content in the cerebellum, showing significant increases at lower blood ethanol concentrations than C57BL/6J mice. The ethanol-induced regulation in C57BL/6J mice appears to be more complex, with decreases in β 2 subunit mRNA content at low blood ethanol concentrations, and increases at higher concentrations. These data suggest that differences between C57BL/6J and DBA/2J mice in the degree of physical dependence (withdrawal) on ethanol may be related to differential sensitivity to ethanol regulation of β 2 subunit expression. 相似文献
19.
β-Casein (β-CN) showing properties of intrinsically unstructured proteins (IUP) displays many similarities with molecular chaperones and shows anti-aggregation activity in vitro. Chaperone activities of bovine and camel β-CN were studied using alcohol dehydrogenase (ADH) as a substrate. To obtain an adequate relevant information about the chaperone capacities of studied caseins, three different physical parameters including chaperone constant ( kc, μM −1), thermal aggregation constant ( kT, °C −1) and aggregation rate constant ( kt, min −1) were measured. Bovine β-CN displays greater chaperone activity than camel β-CN. Fluorescence studies of 8-anilino-1-naphthalenesulfonic acid (ANS) binding demonstrated that bovine β-CN is doted with larger effective hydrophobic surfaces at all studied temperatures than camel β-CN. Greater relative hydrophobicity of bovine β-CN than camel β-CN may be a factor responsible for stronger interactions of bovine β-CN with the aggregation-prone pre denatured molecular species of the substrate ADH, which resulted in greater chaperone activity of bovine β-CN. 相似文献
20.
The lithiation of indole, using a slight excess of n-butyl lithium in THF, followed by methylation and reaction with [Cr(CO) 6] in refluxing dibutyl ether, resulted in the formation of [Cr(η 6- N-methylindole)(CO) 3] (1a) and [Cr(η 6- N-methyl-2-methylindole)(CO) 3] (1b). In contrast, lithiation of quinoline in THF, silylation and the subsequent reaction with [Cr(CO) 6] under similar reaction conditions, afforded [Cr(η 6- N-trimethylsilyl-2-butyl-1,2-dihydroquinoline)(CO) 3] (2) and [Cr(η 6-{2-butyl-1,2,3,4-tetrahydroquinoline})(CO) 3] (3). The formation of [Cr(η 6-2,2′-bis{ N-methylindolyl})(CO) 3] (4) implied lithiation at the 2-position of 1a. However, metallation at the 7-position was also indicated during the same reaction. In the presence of [Mn(CO) 5Br], product 4 and the transmetallation product [Cr(η 6-{7-( N-methylindolyl)Mn(CO) 5})(CO) 3] (5) were isolated. Reaction with titanocene dichloride gave [Cr(η 6-{2-( N-methylindolyl)TiCp 2Cl})(CO) 3] (6), which slowly converted into [TiCp 2{Cr(η 6-2-( N-methylindolyl)(CO) 3} 2] (7). 相似文献
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