Perchlorate and difluorophosphate coordination derivatives of manganese carbonyl

1978 ◽  
Vol 31 (2) ◽  
pp. 267 ◽  
Author(s):  
FL Wimmer ◽  
MR Snow

The complexes Mn(CO)5(OClO3) and Mn(CO)3L2(OClO3) (L = PPh3, P(OPh)3; L2 = bpy*) are formed by abstraction reactions with AgClO4 from the corresponding bromo complexes in dichloromethane. The perchlorato complexes have been characterized by i.r. and mass spectroscopy. They undergo facile substitution reactions in which the perchlorato group is replaced by halide ions (X- = Cl, Br, I), phosphines [PR3 (R = Ph, p- tolyl, m-tolyl), dpe, dpm]* or solvent molecules (MeCN, PhCN, MeOH, Me2CO, py*). Reaction with fluoride ion yields Mn(CO)3F3 plus other decomposition products. When Mn(CO)5X and Mn(CO)3L2X (X = Br) are made to react with AgPF6 in dichloromethane, hydrolysis of the PF6- ion occurs to yield the corresponding difluorophosphato complexes (X = PO2F2-), which have been characterized by i.r., 19F N.M.R. and mass spectroscopy. They are reasonably stable at low temperatures, but decompose at room temperature. The difluorophosphato group is more inert than perchlorato with the rate of substitution decreasing in the order CO ≈ PPh3 > bpy > P(OPh)3.

1982 ◽  
Vol 37 (3) ◽  
pp. 380-385 ◽  
Author(s):  
G. N. Schrauzer ◽  
Laura A. Hughes ◽  
Norman Strampach

Abstract Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3- + OH-→RH + Mo04=. In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2. The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.


1978 ◽  
Vol 33 (9) ◽  
pp. 959-963 ◽  
Author(s):  
H. H. Baalmann ◽  
R. Keizer ◽  
J. C. van de Grampel ◽  
C. Kruk

Aminolysis of cis-NPCl2(NSOCl)2 by piperidine in acetonitrile at room temperature proceeds via a non-geminal substitution pattern. During the first substitution step the reactivity of a SOCl-centre appears to be greater than that of a PCl2-centre. The second and third substitution step successively take place at the PCl2- and remaining SOCl-centre. The different isomeric forms of the mono-, bis-, tris-, and tetrakis(piperidino) derivatives are characterized by means of 31P NMR data. Application of 13C NMR leads in two cases to a structure assignment.


Author(s):  
Ganesh S. Andhale ◽  
Giles D. ◽  
Amit K. Das ◽  
Basavraj Metikurki ◽  
Gurubasavrajswamy PM

In the present study we have synthesized ester prodrugs (Pa-i) of Metoprolol (I) by using pthalic anhydride and derivatives of succinic and maleic anhydride. Different codrugs (COa-i) were synthesized from prodrugs of metoprolol. All the codrugs were characterized by melting point, FTIR, NMR and Mass Spectroscopy. The chemical hydrolysis of COa-i were investigated at the pH 1.2, 6.8 and 7.4. Presence of maleate, methyl maleate, dimethyl maleate and succinate group as linker were found to possess good hydrolysis when compared to that of other substitutes. Among the synthesized codrugs, COf is found to be the best one among the series


2017 ◽  
Vol 20 (K3) ◽  
pp. 83-91
Author(s):  
Xuan Minh Le ◽  
Khanh Duy Nguyen ◽  
Khoa Dang Tran ◽  
Tuan Quoc Tran ◽  
Nghiep Dai Ngo

Chitooligosaccharides (COS) with molecular weight 4633 Da and 84.67% of deacetylation were synthesized by hydrolysis of chitosan by cellulase at room temperature (33 ± 1 ° C). This COS, then, were chemically modified by grafting cinnamaldehyde at amino groups on the COS. Derivatives of N- (cinnamyl) chitooligosaccharides (CCOS) synthesized with 50.64% of yield and 72.22% of extent of substitution had inhibitory activity enzyme collagenase (a group of matrix metalloproteinases, enzyme family related to metastatic ability of cancer). Compared with the positive control, 58.23% of the effective to inhibit collagenase of CCOS at 1000 μg/ml concentrate. In addition, the CCOS cytotoxicity of CCOS was also assessed by MTT method, the results showed that non-toxic derivatives of animal cells and thus can be tested and applied in living systems.


1967 ◽  
Vol 20 (3) ◽  
pp. 447 ◽  
Author(s):  
PJ Shirvington

Acetonitrile is a solvent in which the halogen acids are highly associated. The strongly polarizing Al3+ and Ti4+ ions, when present in acetonitrile with comparable concentrations of water, form very stable hydroxy complexes. These two factors bring about the formation of halogen acids when the metal ions are dissolved in solvent containing halide ions. The results show (at least for aluminium) that it is the dissociation of water rather than of solvent molecules which is involved. Values obtained by polarography for the degrees of hydrolysis of Al3+ and Ti4+ in 25mM H2O and 0.1M tetrapropylammonium chloride were 0.82 and 0.18 respectively. In 0.1M perchlorate media the values for AlCl3 and TiCl4 were 0.45 and 0.40 respectively, indicating that the hydrolysis of Ti4+ is limited as a result of complexing by competing chloride ions. Potentiometric titrations, conductance measurements, and u.v. spectra (for TiCl4) support the polarographic results. No significant hydrolysis could be detected for Mg2+, So3+, Ga3+, and Sn4+ in halide solutions of acetonitrile.


Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.


Author(s):  
Vasil Tsanov ◽  
Hristo Tsanov

Background:: This article concentrates on the processes occurring in the medium around the cancer cell and the transfer of glycoside amides through their cell membrane. They are obtained by modification of natural glycoside-nitriles (cyano-glycosides). Hydrolysis of starting materials in the blood medium and associated volume around physiologically active healthy and cancer cells, based on quantum-chemical semi-empirical methods, is considered. Objective:: Based on the fact that the cancer cell feeds primarily on carbohydrates, it is likely that organisms have adapted to take food containing nitrile glycosides and / or modified forms to counteract "external" bioactive activity. Cancers, for their part, have evolved to create conditions around their cells that eliminate their active apoptotic forms. This is far more appropriate for them than changing their entire enzyme regulation to counteract it. In this way, it protects itself and the gene sets and develops according to its instructions. Methods:: Derived pedestal that closely defines the processes of hydrolysis in the blood, the transfer of a specific molecular hydrolytic form to the cancer cell membrane and with the help of time-dependent density-functional quantum- chemical methods, its passage and the processes of re-hydrolysis within the cell itself, to forms causing chemical apoptosis of the cell - independent of its non-genetic set, which seeks to counteract the process. Results:: Used in oncology it could turn a cancer from a lethal to a chronic disease (such as diabetes). The causative agent and conditions for the development of the disease are not eliminated, but the amount of cancer cells could be kept low for a long time (even a lifetime). Conclusion:: The amide derivatives of nitrile glycosides exhibit anti-cancer activity, the cancer cell probably seeks to displace hydrolysis of these derivatives in a direction that would not pass through its cell membrane and the amide- carboxyl derivatives of nitrile glycosides could deliver extremely toxic compounds within the cancer cell itself and thus block and / or permanently damage its normal physiology.


Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.


1982 ◽  
Vol 47 (5) ◽  
pp. 1382-1391 ◽  
Author(s):  
Jiří Jílek ◽  
Josef Pomykáček ◽  
Jiřina Metyšová ◽  
Miroslav Protiva

Acids IIa-c were prepared by reactions of (4-fluoro-2-iodophenyl)acetic acid with 4-methoxythiophenol, 4-ethoxythiophenol and 4-(ethylthio)thiophenol and cyclized with polyphosphoric acid in boiling toluene to dibenzo[b,f]thiepin-10(11H)-ones IIIa-c. Reduction with sodium borohydride afforded the alcohols IVa-c which were treated with hydrogen chloride and gave the chloro derivatives Va-c. Substitution reactions with 1-methylpiperazine resulted in the title compounds Ia-c out of which the methoxy derivative Ia was transformed by demethylation with boron tribromide to the phenol Id. Compounds Ia-d are very potent neuroleptics exhibiting a clear prolongation of the central depressant and some prolongation of the cataleptic activity.


1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.


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