David M. Rackham

Synthesis, separation and N.M.R. spectra of three double bond isomers of leukotriene a methyl ester

Abstract The synthesis and h.p.l.c. separation of three double bond isomers of leukotriene A methyl ester is described, their stereochemistry being assigned by 1 H N.M.R.

Lanthanide Shift Reagents. XV. Quantitation of D, L-Amino Acid Enantiomers Using Chiral Lanthanide Shift Reagents

Abstract Assay of the DL-enantiomer content of amino acids is an important analytical procedure whether concerned with routine problems in peptide synthesis and degradation or with the more esoteric instance of the organic content of extra terrestrial material2.

Lanthanide Shift Reagents. Paper 16. Binding Constants for Europium Shift Reagent with Sterically Hindered Amine Donors

Abstract In continuation of our work on the measurement of binding constants of organic substrates with Europium shift reagents, we have studied the steric effects of one or more alkyl groups on the binding of a series of eleven amines (anilines, pyridines and piperidines). Both steric and inductive parameters have proved to be important in determining binding constants for carbinols1, aromatic aldehydes and ketones2,3 and esters3,4. The balance of these parameters is discussed for the amines and the results for the three anilines compared with figures derived by Infrared spectroscopy in an earlier study.

Infrared Spectra of Lanthanide Shift Reagent Complexes. I. Anilines

Abstract Lanthanide shift reagents (LSR) are a group of rare earth β-diketonate chelates (Fig. 1a) which havebeen used with enormous success in simplifying complex NMR spectra1,2. Over 1,000 papers have appeared in M since LSR were first reported by Hinckley in 19693.

Lanthanide Shift Reagents XIII the Influence of Phenyl, 1-Adamantyl and Tert-Butyl Substituents on Equilibrium Constants

Abstract We have recently extended our Infrared studies of the binding of anilines with lanthanide shift reagents1 to an NMR examination of hindered phenyl-carbinols2 and a series of aldehydes and ketones related to benzaldehyde and acetophenone3.

Lanthanide Shift Reagents XIV Equilibrium Binding Constants for Europium Shift Reagent with Alkyl and Aryl Esters

Abstract Methods have been developed for measuring the equilibrium binding constants (K) for lanthanide shift reagents with donor substrates. Although Infrared Spectroscopy proved useful1 for determining the binding of substituted anilines to the tris-tetramethylheptanedionate of Ytterbium, it was found that NMR was more sensitive and applicable to a wider range of substrates than simple alcohols and amines2,3. The NMR procedure of progressive

Lanthanide Shift Reagents. Paper 17 Equilibrium Binding Constants for Europium Shift Reagent with NO, SO, and PO Functions

Abstract Recent publications in this series have described the binding constants (K) of the lanthanide shift reagent Eu(thd)3 with aldehydes and ketones1,2 esters2,3 and amines4. In this paper we measure the introduction (or enhancement) of binding properties associated with the changes sulphide to sulphoxide (SO), phosphite to phosphate (PO) and amine to N-oxide (NO) and relate these to hard and soft properties of organic bases.

Lanthanide Shift Reagents XI1,2 Equilibrium Constants for Phenyl Carbinols and Fluorenols

Abstract In a previous publication2, we reported the binding constants for the lanthanide shift reagent Yb (thd)3 in equilibrium with a series of substituted aniline donors. These binding constants were measured by Infrared spectroscopy utilising the changes in amino stretching frequency absorbance at equimolar there is much less hindrance to lanthanide binding and K (93.1) is greatly increased.

Lanthanide Shift Reagents. Paper 18. Equilibrium Binding Constants for Europium Shift Reagent with Nitrogen Heterocycles

Abstract Paper 16 in this series1, 2, 3 was concerned with the equilibrium binding constants (K) of the shift reagent Europium tris (2, 2, 6, 6-tetramethylheptane-3, 5-dionate), Eu(thd)3, with primary, secondary and tertiary amines. One nitrogen heterocycle, pyridine, and two of its derivatives (see Table) were included. In the present paper we describe the binding constants for a further 9 nitrogen containing heterocycles and relate these to basicity and steric effects.

Lanthanide Shift Reagents. Paper 21. Interaction of Arenes with Silver/Lanthanide Shift Reagent and Comparison with Chromium Tricarbonyl Complexes

Abstract Lanthanide shift reagents can bring about dramatic simplifications of highly complex NMR spectra1,2. The applicability of the commonest of these (the thd and fod chelates of Eu, Pr and Yb) has been restricted to those molecules possessing a suitable N, O or S donor atom, although they may turn up in unusual guises, e.g. in quaternary ammonium compounds3.