Albert R. Norris
University of Oxford
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Albert R. Norris.
Journal of Inorganic Biochemistry | 1981
Spencer E. Taylor; Erwin Buncel; Albert R. Norris
Proton nmr spectroscopic evidence is presented for methylmercury(II) binding to the deprotonated amino groups in adenosine, 9-methyladenine, guanosine, 1-methylguanosine, and cytidine under basic conditions. Except for the guanosine case, 1H nmr spectra of the products from aqueous or ethanolic 1:1 mixtures of substrate and MeHgOH are consistent with methylmercuration of the deprotonated amino groups. Guanosine undergoes initial binding of MeHg to N1, and a second equivalent of MeHgOH is necessary to effect amino binding. The nmr spectra of the complexed adenine derivatives suggest that different geometrical isomers exist in (CD3)2SO solution, reflecting the partial double bond character of the C6N bond in these systems. Using a correlation relating the magnitude of the 199Hg-1H coupling constant (J) for MeHg-ligand complexes with the ligand pKa (J = −3.88 pKa + 248.5, extending over 13 pK units, based on a variety of N and O donor ligands), estimates (± 0.3 pK unit) of the pKas of the amino groups of the above substrates have been made. In this way, pKa values of 15.5 (cytidine), 17.0 (adenosine and 9-methyladenine), 15.1 (guanosine), and 14.9 (1-methylguanosine) are obtained. In the cases where comparisons with literature pKa data can be made, good agreement is found.
Canadian Journal of Chemistry | 1980
Albert R. Norris
The reactions of 2,4,6-trinitrotoluene (TNT) and TNT-d3 (deuterated methyl group) with tetra-n-butylammonium tert-butoxide and with potassium tert-butoxide (KOBut), in the absence and presence of the crown ethers 18-crown-6, and dicyclohexyl-18-crown-6, have been studied kinetically in tert-butanol at 30.0 °C. Evidence is presented to support the suggestion that, at ratios of crown ether to base > 1, the reactive base species is free tert-butoxide ion and that this rapidly reacts with TNT or TNT-d3 to form, in each case, a mixture of σ-complex and purple anion. Specific rate constants for the reactions of free tert-butoxide ion and ion-paired KOBut with TNT and TNT-d3 to form both σ-complex and purple anion are compared.
Journal of The Chemical Society, Chemical Communications | 1979
Erwin Buncel; Albert R. Norris; William J. Racz; Spencer E. Taylor
The increased lability of purine nucleoside C(8)–H bonds upon co-ordination of a metal ion to the adjacent N(7) position has been used to explain the observed formation of C(8)-bonded inosine and guanosine methylmercurials, these being the first reported carbon bound species formed from the interaction of nucleosides with organomercurials.
Canadian Journal of Chemistry | 1974
Erwin Buncel; Albert R. Norris; Kenneth Edwin Russell; Peter Jura Sheridan; Harold Wilson
The reaction of sodium isopropoxide with 2,4,6-trinitrotoluene (TNT) and TNT-d3 (deuterated methyl group) in isopropanol has been investigated using stopped-flow techniques. Two absorbing species, identified as a σ-complex and the TNT anion (TNT−) are formed in this reaction. The formation of TNT− involves a rate determining proton transfer as shown by the observation of an isotope effect A spectrum of the σ-complex was calculated from initial rate data and was observed experimentally at low temperatures (λmax = 435, 495 nm). The effects of added salts on rates and equilibria of σ-complex and TNT− formation have been determined.In this study the possible involvement of free alkoxide ions and ion-pairs in the reactions has been evaluated. The free alkoxide ion is the more reactive species in deuteron transfer whilst in σ-complex formation the free ions and ion-pairs have comparable reactivity. A rationale of this behavior is presented.The kinetic parameters are, for deuteron transfer: kiD = 850 ± 100 M−1s−...
Journal of The Chemical Society-perkin Transactions 1 | 1980
Erwin Buncel; Masashi Hamaguchi; Albert R. Norris
Reaction of the title compound as the hydrochloride salt with Et3N in dimethyl sulphoxide or dimethylformamide solution gave rise rapidly to the spiro-complex (9), followed by slow formation of (12), the product of intramolecular nitro-displacement. When NaOMe in DMSO–MeOH was used as the base, the overall conversion to (12) was much more sluggish. Reactivities in the two systems are discussed and the more facile reaction with Et3N is suggested to arise mainly as a result of general acid-catalysed ring-opening of (9) by Et3NH+, thus increasing the concentration of free amine, the reactive species in the displacement process. The results tend to rule out alternative mechanisms of nitro-displacement in which the spiro-complex serves as the reactive species in product formation.
Journal of The Chemical Society-perkin Transactions 1 | 1977
Erwin Buncel; Noemi Chuaqui-Offermanns; Albert R. Norris
The reaction of 7-methoxy-4-nitrobenzofurazan 1-oxide with methoxide ion in dimethyl sulphoxide–methanol (or in dimethyl sulphoxide–methanol–chloroform) gives rise to a kinetically controlled C-5 adduct and a thermo-dynamically controlled C-7 adduct. Some unusual features in the n.m.r. spectra are discussed.
Inorganic Chemistry | 1981
Erwin Buncel; Albert R. Norris; William J. Racz; Spencer E. Taylor
Canadian Journal of Chemistry | 1982
Erwin Buncel; Albert R. Norris; Spencer E. Taylor; William J. Racz
Canadian Journal of Chemistry | 1977
Erwin Buncel; Noemi Chuaqui-Offermanns; Brian K. Hunter; Albert R. Norris
Canadian Journal of Chemistry | 1985
Erwin Buncel; Rajesh Kumar; Albert R. Norris; André L. Beauchamp