- Kinetics of Corrosion of Ruthenium Dioxide Hydrate by CeIV Ions
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The kinetics of oxidative dissolution of RuO2*xH2O to RuO4 by CeIV ions are studied.Under conditions of a low IV>: ratio (e.g. 0.35:1) and a high background concentration of CeIII ions (which impede dissolution) the initial reduction of CeIV ions is due to charging of the RuO2*xH2O microelectrode particles.The initial rate of charging depends directyl upon and has an activation energy of 25 +/- 5kJ mol-1.Under conditions of a high IV>: (e.g. 9:1) and a low background III> the reduction of CeIV ions is almost totally associated with the dissolution of RuO2*xH2O to RuO4, e.e. not charging.The kinetics of dissolution obey and electrochemical model in which the reduction of CeIV ions and the oxidation of RuO2*xH2O to RuO4 are assumed to be highly reversible and irreversible processes, respectively, mediated by dissolving the microelectrode particles of RuO2*xH2O.Assuming this electrochemical model, from an analysis of the kinetics of dissolution the activation energy for this process was estimated to be 39 +/- 5 kJ mol-1 and the Tafel slope for RuO2*xH2O corrosion was calculated to be 15 mV per decade.The mechanistic implications of these results are discussed.
- Mills, Andrew,Davies, Hefin
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- Corrosion of Ruthenium Dioxide Hydrate by CeIV Ions and other Oxidants
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A 'test system' has been developed in order to investigate the corrosion stabilities and O2-catalytic activities exhibited by samples of RuO2*xH2O when exposed to a strong oxidant such as CeIV ions.The RuO2*xH2O samples included commercial powders as well as one prepared in the laboratory.The majority of these samples, including the prepared samples, were unstable towards anodic corrosion ( ca. 86percent corrosion) and showed little O2 catalityc activity (O2 yields 8percent).The small amount of O2 evolved was believed to originate from water bound in the oxide powder.These RuO2*xH2O samples appeared, from thermogravimetric analysis (t.g.a.) and differential gravimetric analysis (d.t.g.a.) measurements, to be highly hydrated (H2O content = 24-26percent).A minority of commercial RuO2*xH2O powders, when analysed by t.g.a. and d.t.g.a., were found to be in a partially dehydrated form (H2O content = 18percent).These samples showed a much greater resistance towards corrosion (9-13percent corrosion) and were able to mediate the oxidation of water (O2 yield = 92percent) by CeIV ions.The corrosion of RuO2*XH2O by other oxidants, e.g.BrO3-, MnO4- or PbO2, was also studied and the results are discussed.The implications of these findings are considered.
- Mills, Andrew,Giddings, Susan,Patel, Ila
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- Oxidative Dissolution of Ruthenium Dioxide Hydrate by Periodate Ions
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The results of a kinetic study of the oxidative dissolution of ruthenium dioxide hydrate to ruthenium tetroxide by periodate ions, IO4(1-), in acidic solution are described.The kinetics of dissolution give a good fit to a 'soft-centre' model in which the
- Mills, Andrew,Sawunyama, Phillip
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- Two crystalline modifications of RuO4
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RuO4 was prepared by oxidation of elemental ruthenium. Two different modifications were obtained and investigated by X-ray single crystal diffraction. RuO4-I has cubic symmetry (P4;-3n,Z=8,a=8.509(1)A) , and two independent tetrahedral molecules are present in the unit cell. Within the standard uncertainties in both molecules the distances Ru-O are 1.695 A. The second modification, RuO4-II, is monoclinic (C2/c,Z=4,a=9.302(4)A,b=4.3967(10)A,c=8.454(4)A,β=116. 82(3)°) and isotypic with OsO4. There is one independent molecule in the unit cell, which shows distances Ru-O of 1.697 and 1.701 A, respectively.
- Pley, Martin,Wickleder, Mathias S.
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- The reduction of dioxotetrachlororuthenate(VI) to hexachlororuthenate(IV) in a basic 1-butylpyridinium chloride-aluminium(III) chloride ionic liquid
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The anion [RuO2Cl4](2-) is sufficiently stable in a basic [NBupy]Cl-AlCl3 ([NBupy]=1-butylpyridinium) ionic liquid (44.44 mol% AlCl3) at ambienttemperature to enable its solution electronic absorption spectrum to be recorded for the first time, but is slowly reduced (k=1.45E-5 s**-1; t( 1/2)=13.3 h) in a pseudo-first-order process to give predominantly [RuCl6](2-), according to [RuO2Cl4](2-) + 2[AlCl4](-) [RuCl6](2-) + 2 [AlOCl2](-) + Cl2. A by-product of the reduction process was tentatively identified as [Ru2OCl10](4-), and was believed to be formed according to 2[RuO2Cl4](2-) + 3[AlCl4](-) [Ru2OCl10](4-) + 3 [AlOCl2](-) + 2Cl2. This is the first documented irreversible transfer of an oxide ion from an isolable transition metal complex to tetrachloroaluminate in an ambient-temperature ionic liquid.
- Crisp, Russell I.,Hussey, Charles L.,Seddon, Kenneth R.
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- A study of zeolite NaY-supported ruthenate in the oxidation of alcohols
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Sodium ruthenate was supported on zeolite NaY. This compound was found to be an efficient and selective catalyst, with a range of co-oxidants, for the room temperature oxidation of internal and external alcohols to their respective carbonyl products.
- Friedrich, Holger B.,Singh, Nirad
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- A general route for RuO2 deposition on metal oxides from RuO4
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A novel method for the deposition of RuO2 from RuO 4(g) on diverse metal oxides has been developed by grafting dopamine onto the otherwise un-reactive metal oxide surface. Oxygen evolution reaction on TiO2 and the photoelectrochemical improvement of WO3 by deposition of RuO2 are just a few examples where this novel deposition method can be used.
- Kleiman-Shwarsctein, Alan,Laursen, Anders B.,Cavalca, Filippo,Tang, Wei,Dahl, Soren,Chorkendorff, Ib
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- Kinetics of Redox Dissolution of Soft-centre Particles
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A model is developed which describes the kinetics of redox dissolution of a powder comprising soft-centre particles, i.e. particles with a comparatively inert, outer layer and a more reactive, inner core.The model is then used to interpret the non-simple cubic rate law kinetics exhibited in the oxidative dissolution of partially dehydrated samples of ruthenium dioxide hydrate by bromate ions under acidic conditions.
- Mills, Andrew,Worsley, David
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- Electron Spin Resonance Spectra of the Perruthenate(VII) Ion, (1-)
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Electron spin resonance spectra of the (1-) ion A, where A = NPrn4, N(PPh3)2 or PPh4> in frozen glasses of dichloromethane at ca. 90 K have been recorded; for A = NPrn4, gx = 1.93, gy = 1.98 and gz = 2.06.The spectrum of (1-) (and its electronic spectrum) have been interpreted and compared with those of an alkaline aqueous solution containing ruthenium(VII) species.The ESR spectrum of powdered potassium ruthenate(VI), trans-K2, at ca. 90 K was also recorded, and the preparation of , a new salt of (1-), is described.
- Dengel, Andrew C.,Gibson, John F.,Griffith, William P.
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- A comparative study of the ruthenium(VI)dioxocarboxylato salts, [PPh4][RuO2(OCOR)Cl2] (R = CH3, CF3, C6H5, C6F5, C5H11), in the oxidation of alcohols
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The compounds [PPh4][Ru(O)2(OCOR)Cl2] (R = CH3 1a, CF3 1b, C6H5 1c, C6F5 1d, C5H11 1e) were prepared and fully characterised. The fluorinated compounds 1b and 1d were obtained in significantly higher yields than their protonated analogues 1a and 1c and compound 1b was found to be a clearly superior stoichiometric oxidant to compound 1a. The compounds 1a-1e were examined as catalytic oxidants for the oxidation of 1- and 2-hexanol, to hexanal and 2-hexanone respectively, with the co-oxidants H2O2, NaOCl, t-BuOOH, N-methylmorpholine-N-oxide, Me3NO, O2, C6H5IO and Bu4NIO4. Compounds 1c and 1d were further studied in the catalytic oxidation of a wide range of alcohols (using N-methylmorpholine-N-oxide and Bu4NIO4 as co-oxidants) and found to give the corresponding aldehydes or ketones very selectively, with no attack on sensitive linkages or functional groups and no over-oxidation products. Compounds 1c and 1d were also supported on poly(4-vinylpyridine) to give active catalysts.
- Friedrich, Holger B.,Gokul, Vikash
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- Structural and Magnetic Studies of ABO4-Type Ruthenium and Osmium Oxides
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Oxides of the form ABO4 with A = K, Rb, Cs and B = Ru and Os have been synthesized and characterized by diffraction and magnetic techniques. For A = K the oxides adopted the tetragonal (I41/a) scheelite structure. RbOsO4, which crystallizes as a scheelite at room temperature, underwent a continuous phase transition to I41/amd near 550 K. RbRuO4 and CsOsO4 were found to crystallize in the orthorhombic (Pnma) pseudoscheelite structure, and both displayed discontinuous phase transitions to I41/a at high temperatures. CsOsO4 was determined to undergo a phase transition to a P21/c structure below 140 K. CsRuO4 crystallizes with a baryte-type structure at room temperature. Upon heating CsRuO4 a first order phase transition to the scheelite structure in I41/a is observed at 400 K. A continuous phase transition is observed to P212121 below 140 K. DC magnetic susceptibility data is consistent with long-range antiferromagnetic ordering at low temperatures for all compounds except for CsOsO4, which is paramagnetic to 2 K. The effective magnetic moments are in agreement with the spin only values for an S = 1/2 quantum magnet. Effective magnetic moments calculated for Os compounds were lower than their Ru counterparts, reflective of an enhanced spin orbit coupling effect. A magnetic structure is proposed for RbRuO4 consisting of predominately antiferromagnetic (AFM) ordering along the 001 direction, with canting of spins in the 100 plane. A small ordered magnetic moment of 0.77 μB was determined.
- Avdeev, Maxim,Brand, Helen E. A.,Injac, Sean,Kennedy, Brendan J.,Turner, Peter,Wang, Chun-Hai,Yuen, Alexander K. L.
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p. 2791 - 2802
(2020/03/17)
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- Ultrasonic-assisted ruthenium-catalyzed oxidation of some organic compounds in aqueous medium
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Ultrasonic generation of ruthenium complexes K2[RuO3(OH)2] and [RuO4] is reported from K2[RuCl5(H2O)] with excess K2S2O8 in 1 M KOH and/or with excess KIO4 in biphasic solvent system (H2O/CH2Cl2/CH3CN) at room temperature. Dehydrogenation of some primary amines to nitriles and primary alcohols to their respective acids by K2[RuCl5(H2O)] with excess K2S2O8 at room temperature was reported. A number of nitriles were hydrated to amides by the same catalyst system at 100 °C. The oxidation of two arenes and four alkenes to their aldehydes, ketones or acids by K2[RuCl5(H2O)] with excess KIO4 using ultrasonic irradiation technique was also reported. Cyclic voltammetric, electronic and Raman spectroscopic techniques have been used to elucidate the nature of the active species present in these catalytic oxidation reactions.
- Shoair, Abdel Ghany F.
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- Synthesis and antimicrobial activity of novel oxysterols from lanosterol
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Chemically diverse oxysterols and their synthetic manipulations were carried out from variety of Δ8(9)-lanosterol derivatives and evaluated for their in vitro antimicrobial activities. Most of the synthesized oxysterols exhibited significant antifungal activity against the tested strains.
- Shingate, Bapurao B.,Hazra, Braja G.,Salunke, Deepak B.,Pore, Vandana S.,Shirazi, Fazal,Deshpande, Mukund V.
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p. 11155 - 11163
(2014/01/06)
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- Five-membered carbocyclic and heterocyclic inhibitors of neuraminidases
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Disclosed are compounds of the formula: which are useful for inhibiting neuraminidases from disease-causing microorganisms, especially, influenza neuraminidase. Also disclosed are compositions and methods for preventing and treating diseases caused by microorganisms having a neuraminidase, processes for preparing the compounds and synthetic intermediates used in these processes.
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- Highly efficient use of NaOCI in the Ru-catalysed oxidation of aliphatic ethers to esters
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The selectivity of α-oxidation of ethers to esters via RuNaOCI can be dramatically improved by pH control, at high substrate to catalyst ratios using a stoichiometric amount of hypochlorite in biphasic media at room temperature.
- Gonsalvi, Luca,Arends, Isabel W.C.E.,Sheldon, Roger A.
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p. 202 - 203
(2007/10/03)
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- Ozonolysis for the preparation of high oxidation-state transition-metal complexes and the crystal structure of [PPh4]2[Ru2O(μ-OCOEt)2Cl 6]
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An ozone-oxygen mixture has been used to generate a number of high oxidation-state transition-metal complexes in aqueous solution at room temperature by simple and safe procedures. Species so prepared include the oxo species [OsVIIIO4], [RuVIIIO4], cis-[OsVIIIO4(OH)2]2-, trans-[OsVIO2(OH)4]2-, [RuVIIO4]-, trans-[RuVI(OH)2O3]2-, [VVO4]3- and the new complex [PPh4]2[Ru2O(μ-OCOEt)2Cl 6] 1 for which the crystal structure is reported; the polyoxometalates K6[MnIVMo9O32]·10H 2O, K8[MnIVW6O24]·6H 2O, [NH4]2[MnIVMo6H6O 24]·20H2O and Na8[CeIVW10O36]·8H 2O; the chloro complexes [MIVCl6]2- (M = Pt, Pd, Ir) and [AuIIICl4]-, and manganic acetate [MnIII(OAc)3]·2H2O. Ozonolytic oxidation of coordinated benzylamine in cis-[RuII(bipy)2(NH2CH2Ph) 2][PF6]2 to coordinated benzonitrile in cis-[RuII(bipy)2(NCPh)2][PF6] 2 is also reported.
- Bailey, Alan J.,Griffith, William P.,Marsden, Stephen P.,White, Andrew J. P.,Williams, David J.
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p. 3673 - 3677
(2007/10/03)
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- Studies on Transition-Metal Oxo and Nitrido Complexes. Part 11. New Oxo Complexes of Ruthenium as Aerobically assisted Oxidants, and the X-Ray Crystal Structure of *3.5H2O
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The new complexes t-py), nicotinic acid (Hnic), isonicotinamide (isna), pyridine-2-carboxylic acid (Hpyca), or1/2(2,2'-bipyridyl) (bipy)> have been prepared and the X-ray crystal structure of another member of the series, *3.5H2O, determined , a = 7.943(1), b = 8.952(2), c = 9.257(3) Angstroem, α = 98.76(2), β = 95.75(2), γ = 98.08(1) deg, Z = 1, R = 0.065>.New complexes are also reported of the types trans-2+ , trans- (L = 4But-py or 4-chloropyridine), trans- and trans-- (L = py, 4But-py, 3-methylpyridine, or 3,4-dimethylpyridine).Vibrational spectra, structures and reactions of these species are discussed: they function as overall four-electron oxidants (eight-electron in the case of , converting primary alcohols into aldehydes and secondary alcohols into ketones, and function catalytically with N-methylmorpholine N-oxide or iodosylbenzene as co-oxidant.The most soluble of them, trans-*3.5H2O, trans-t-py)4>, trans-2+, and trans-t-py)>-, will also effect such oxidation of alcohols with dioxygen as co-oxidant.
- Dengel, Andrew C.,El-Hendawy, Ahmed M.,Griffith, William P.,O'Mahoney, Caroline A.,Williams, David J.
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p. 737 - 742
(2007/10/02)
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- Studies on Transition-Metal Oxo and Nitrido Complexes. Part 10. New Oxo-Ruthenium and Oxo-Osmium Pyridine Complexes, and Use of the Former as Catalysts for Oxidation of Alcohols
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The new complexes trans-(2+), trans-(2+), trans- (M=Ru or Os; X=Cl or Br; py= pyridine) and trans- are reported.Both tans-(2+) and trans- in CH2Cl2 are efficient oxidants for primary alcohols to aldehydes and secondary alcohols to ketones, and function catalytically, with N-methylmorpholine N-oxide (mmo) or n4> as co-oxidants.A simple preparation of trans- and the isolation of , , and OsO2L2(O2C6H10)> (L=pyridine N-oxide) are also reported. Complexes were characterised by Raman, i.r. and (1)H n.m.r.spectroscopy.
- El-Hendawy, Ahmed M.,Griffith, William P.,Taha, Fatma I.,Moussa, Mahmoud N.
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p. 901 - 906
(2007/10/02)
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- Reactions and Catalytic Properties of Ruthenium Dioxide Hydrate with Aqueous Solutions of Cerium(IV)
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The redox catalytic properties of ruthenium dioxide hydrate (RuO2*xH2O) were studied using a test system of Ce(4+) in 0.5 mol dm-3 H2SO4.In powder form RuO2*xH2O appeared a poor redox catalyst unless bound to an inert support, such as titanium dioxide (TiO2).This was attributed to the production of ruthenium tetraoxide (RuO4), which was observed with RuO2*xH2O and a RuO2*xH2O-TiO2 mixture but not with a TiO2-bound RuO2 catalyst.In the absence of a catalyst, or when TiO2 or Al2O3 were used, no decay of the Ce(4+) was observed (t>200 h).
- Mills, Andrew
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p. 1213 - 1216
(2007/10/02)
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- Syntheses and crystal and molecular structures of hexaaquaruthenium(II) p-toluenesulfonate and hexaaquaruthenium(III) p-toluenesulfonate, [Ru(H2O)6](C7H7SO3) 2 and [Ru(H2O)6](C7H7SO3) 3·3H2O
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Crystals of Ru(H2O)6(tos)2 (II) (tos- is p-toluenesulfonate) were grown from aqueous Ru(H2O)62+ solutions obtained by reduction of RuO4 solutions with metallic lead. Crystals of Ru(H2O)6(tos)3·3H2O (III) were grown from aqueous Ru(H2O)63+ obtained by oxidation of a Ru(H2O)62+ solution with O2. For II the space group is P1 with cell parameters a = 6.138 (1) A?, b = 7.287 (2) A?, c = 12.423 (4) A?, α = 92.22 (2)°, β= 94.82 (2)°, γ = 107.13 (2)°, and Z = 1. For III the space group is C2/c with lattice constants a = 25.466 (7) A?, b = 7.235 (4) A?, c = 35.113 (8) A?, β= 93.97 (2)°, and Z = 8. The structure of II was refined to R = 3.3% for 2302 reflections with Fo > σ(Fo) the structure of III, to R = 5.2% for 2989 reflections with Fo > σ(Fo). In both structures Ru(H2O)6 octahedra are linked by hydrogen bonds to the SO3 groups of the anion, the O-H···O distances ranging from ~2.5 to 3.0 A?. The average metal-oxygen distance is 2.122 (16) A? for Ru(II)-OH2 and 2.029 (7) A? for Ru(III)-OH2. The effect of the change in bond length on the rate of the Ru(H2O)63+/2+ self-exchange reaction is discussed.
- Bernhard, Paul,Bürgi, Hans-Beat,Hauser, Jürg,Lehmann, Hans,Ludi, Andreas
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p. 3936 - 3941
(2008/10/08)
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- A Method for the Preparation of Anhydrous Ruthenium(VIII) Oxide
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RuO4 can be obtained from Ru metal and ozone at room temperature.This procedure yields pure RuO4 directly, and there are no problems of separation from water as in standard methods of preparation. - Keywords: Ruthenium(VIII)-oxid
- Loessberg, Rainer,Mueller, Ulrich
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- Preparation of β-lactams and intermediates therefor
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Novel process for the preparation of β-lactams of the formulae: STR1 wherein R' represents lower alkyl, aryl or aryl (lower alkyl), R" represents hydrogen or lower alkyl or R' and R" together with the carbon atoms to which they are attached represent lower cycloalkyl, R'" represents lower alkyl or a group --OR, wherein R represents lower alkyl, X1, Y1 and Z1 are hydrogen or selected organic radicals and R1 represents an acyl group; which successively involves reacting an 1,3-dicarbonyl compound of the formula: STR2 with glycine in the presence of a base to form a vinylamino salt of the formula: STR3 wherein M1+ is the cation of the base, activating the carboxyl group of said vinylamino salt with an appropriate activating agent and reacting the activated compound in the presence of a tertiary base with an imino compound of the formula: STR4 to form the corresponding α-vinylamino-β-lactam of formula IV A and if desired, subjecting said β-lactam to mild acid hydrolysis to obtain the corresponding α-amino-β-lactam of formula V A and if desired, acylating said α-amino-β-lactam with an appropriate acylating agent to obtain a corresponding α-acylamino-β-lactam of formula VI A.
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- Monosaccharides and products resulting therefrom
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The invention provides novel compounds of the formula: STR1 wherein B is α- or β- and represents a hydrocarbyl group in which the α-carbon atom is activated by a suitable blocked or unblocked functional group rendering it susceptible to oxidation. The compounds are useful as intermediates in the preparation of prostaglandins and prostaglandin analogues. The invention also provides a stereospecific method of producing these intermediates.
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- Carbazole acetic acid derivatives
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Tetrahydrocyclopent[b]indole-3-acetic acid, tetrahydrocarbazole-1-acetic acid and hexahydrocyclohept[b]-indole-6-acetic acid derivatives in which the carbon bearing alkyl, lower alkenyl or lower cycloalkyl are disclosed. The compounds are useful antiinflammatory agents and methods for their preparation and use are described.
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