bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of primulagenin A. IV. Ring expansion in Oleana-12,15-diene-3b,28-diol and the related 13(18),15-diene isomer
Authors: Hensens OD , Lewis KG , Tucker DJ
Published: September 2010

Treatment of
oleana-12,15-diene-3β,28-diol 3-acetate with a cold pyridine solution of
p-toluene-sulfonyl chloride leads to expansion of
ring D with the formation of 28-nor-D(16a)-homo-oleana-12,15,17(18)-
trien-3β-yl acetate (7). Under more vigorous conditions a mixture of the
D-homo compound (7) and a double bond isomer (11) is obtained. Subjection of
oleana-13(18),15-diene-3β,28- diol 3-acetate to similar reflux conditions
also forms the D-homo compound (7).
The stereochemistry of proton removal in the formation of π-allyl palladium complexes from steroid 4-En-3-ones
Authors: Collins DJ , Jackson WR , Timms RN
Published: September 2010

Reaction of (6β-2H)-
and (6α-2H)-cholest-4-en-3-one with palladium(II) chloride in
dry tetrahydro- furan gives the α-4-6-η-PdCl compound with highly
stereoselective loss of the 6β deuterium or proton. The mechanistic
implications of this stereoselectivity are discussed.
Pigments of some echinoderms collected from Western Australian waters
Authors: Francesconi KA
Published: September 2010

Sixteen species belonging
to the phylum Echinodermata have been surveyed for the presence of colouring
matters by thin-layer chromatography. Comantheria briareus (Bell) yielded the
linear naphthopyrones comantherin (1), neocomantherin (2), a new pigment, 5,8- dihydroxy-6-methoxy-2-propyl-4H-naphtho[2,3-b]pyran-4-one
(3), and the angular naphthopyrone comaparvin (4). Comatula
solaris Lamarck afforded the anthraquinone rhodolamprometrin (5) and Comatula rotalaria
Lamarck yielded rhodocomatulin 6-methyl ether (6). Both C. solaris and C.
Rotalaria afforded rhodocomatulin 6,8-dimethyl ether (7).
Anomalous acetoxylation of aromatic nuclei: some structural requirements in the substrate
Authors: Bandaranayake WM , Riggs NV
Published: September 2010

For certain aromatic
nuclei, bromination in acetic acid and in the
presence of pyridine is accompanied by nuclear acetoxylation.
As first observed with galbulin, when two alkoxyl groups, one meta and one para to a benzylic centre of the substrate are present, acetoxylation occurs at the intervening ortho position. Under the given
conditions, acetoxylation occurs at position 8 of
6,7-dimethoxy-1-phenyl-1,2,3,4,-tetrahydronaphthalene, and at position 2 of
3,4,-dimethoxy diphenyl- and triphenyl-methanes. Acetoxylation does not occur in the absence of either of
the alkoxy groups or in the absence of pyridine, nor
does it occur in the pendant ring of 1-(3�,4�-dimethoxypheny1)-
1,2,3,4-tetrahydronaphthalene. These results are consistent with the earlier
suggestion that the reaction occurs by way of initial oxidative formation of a
doubly benzylic cation.
Synthesis of the fungal pigment 2,7-Dihydroxy-5-methyl-1,4-naphthoquinone
Authors: Cameron DW , Feutrill GI , Griffiths PG
Published: September 2010

The title compound has been
synthesized and shown to be identical with material derived from the fungus Verticillium lamellicola
by comparison of their respective dimethyl ethers.
Configuration interaction, ionization potentials and valence-bond aspects of the rotation barrier for dinitrogen tetroxide
Authors: Harcourt RD
Published: September 2010

The results of recent He II studies of the N2O4 photoelectron spectrum are used to obtain an empirical estimate for a cis O-O core resonance integral, β°oo'. This integral is associated with the overlap between pairs of cis oxygen in-plane (2pπ) orbitals (which are doubly occupied in valence-bond structures of types (A) and (B)), and is therefore relevant for an analysis of the cis O-O overlap contribution to the barrier to rotation around the NN bond of N2O4. Limited SCF-CI calculations for the planar and skew conformations give a rotation barrier of 7.2 kJ mol-1 (cf. expt., 8.4-12.6 kJmol-1) when the NN σ-bond order is 0.525 for the planar conformation. The CI expression for the rotation barrier is expressed as a sum of cis O-O overlap, Coulomb and exchange terms, of which the cis O-O overlap contribution has the largest magnitude. The sensitivity of the magnitude of the rotation barrier to variation in the value of the NN σ-bond order is also demonstrated.
A valence-bond analysis of the cr wavefunction provides further support for an earlier
conclusion that resonance between covalent (NO2NO2) and ionic (NO2+ NO2- and NO2- NO2+)
structures provides the valence-bond explanation for the origin of the cis O-O overlap contribution
to the rotation barrier. An unexpected result obtained from this analysis is that, although resonance
between covalent and ionic structures of types (A) and (B) alone is not cis O-O overlap dependent,
this type of resonance does provide a contribution to the cis O-O overlap stabilization of the planar
conformation when it is coupled to the other types of covalent-ionic resonance, which arise when
the oxygen 2pσ-electrons of (A) and (B) delocalize. Each of the latter types of resonance alone is
cis O-O overlap dependent.
Derivatives of isatin in aqueous solution. I. Kinetics of ring opening of Isatin-5-sulfonate
Authors: Stunzi H
Published: September 2010

The reactions of
isatin-5-sulfonate anion (si-) which cause
a hysteresis in pH titrations were studied by
pH-metric and n.m.r, spectroscopic methods. Rapid alkalimetric
titrations [I 0.15 M (KNO3),37�]
gave the pKa value
corresponding to the addition of OH- to si-
[pKa(ring) 9.55]. The slow
ring opening to the sulfonatoisatate dianion (sia2-) led to a drift of the pH values
towards an equilibrium buffer region. Its pKa,
value [pKa(eq) 3.44] corresponds to the reaction si-+H2O
↔
sia 2-+H+ Rapid back-titration gave the pKa value of the ring-opened species Hsia-
[pKa(open) c. 1.3]. The rate law for the ring
opening d[sia]/dt=k2 [siOH](OH)+k1*[si] was obtained from the rate of change of pH. N-Methylisatin-5-sulfonate behaves
analogously.
Thermodynamic properties of the binary molten salt systems, PbBr2-KBr, PbBr2-RbBr and PbBr2-CsBr, by measurement of the electromotive forces of galvanic cells
Authors: Bloom H , White MS
Published: September 2010

The electromotive forces of
galvanic cells for the formation of PbBr2 in the molten binary salt
systems, PbBr2-KBr, PbBr2,-RbBr and PbBr2-CsBr,
have been measured. Activities, activity coefficients and partial molar free
energies have been calculated for each component of the three systems. Integral
free energies of mixing have also been calculated. Various models of mixing of
molten salts have been applied to the results. The systems contain complex ions,
probably mixtures of PbBr42-, PbBr64-
with some PbBr3-.
Mass spectral and 13C N.M.R. analyses of aminoglycoside aminocyclitols modified by enzyme-catalysed reactions
Authors: Coombe RG , George AM
Published: September 2010

Chemical and physical
analytical methods, including mass spectrometry and 13C n.m.r., have
been applied to the evaluation of the structures of the inactivated products of
enzyme-mediated transferase reactions. Evidence is presented for the assignment
of structures for the products of three enzymic reaction mechanisms: O-adenylylation, O-phosphorylation and N-acetylation.
Constituents of Eupomatia species. VII. Dienone-phenol and dienol-benzene rearrangements in the eupodienone-1 series
Authors: Bowden BF , Read RW , Taylor WC
Published: September 2010

Rearrangement of
eupodienone-1 and derivatives, including certain dienols, under a variety of
acidic conditions produced dibenzocyclooctene derivatives. Spectroscopic
evidence and chemical degradation showed that in the rearrangements alkyl
rather than aryl group migration had occurred. The stereochemistry of the
products is discussed.
The chemistry of pyrrolic compounds. XLVII. The synthesis of a possible biogenetic precursor of haem a and its relationship to the prosthetic group ofmyeloperoxidase and to cryptoporphyrin a
Authors: Clezy PS , Fookes CJR
Published: September 2010

The synthesis of
18-demethyl-18-formylprotoporphyrin dimethyl ester is described and the role of
this compound as an intermediate in the biosynthesis of haem a is considered. A possible relationship
between a compound of this structure and the prosthetic group of myeloperoxidase
is discussed. The cryptoporphyrin a fraction of ox heart extracts has been
reexamined and shown to consist of a mixture of Spirographis porphyrin and its isomer which presumably arise from
the in vitro oxidation of the vinyl
groups in protoporphyrin.
13C spectral parameters of some polycyclic hydrocarbons. II. Bicyclo[3,1,1]heptane, Tricyclo[3,1,1 ,03,6]heptane, Tricyclo[3,3,0,02,6]octane and Bicyclo[1,1,1]pentane
Authors: Della EW , Cotsaris E , Hine PT , Pigou.P.E .
Published: September 2010

Carbon-13 chemical shifts
and one-bond carbon-hydrogen coupling constants of bicyclo[3,1,1]- heptane,
tricyclo[3,1,1,03,6]heptane, tricyclo[3,3,0,02,6]octane
and bicyclo[1,1,1]pentane are reported.
Reactions of 2,5-Dihydrothiophen and S-substituted derivatives with bases. Preparations of 1-(Alkylthio)buta-1,3-dienes and the corresponding sulfoxides and sulfones
Authors: Crumbie RL , Ridley DD
Published: September 2010

Under certain conditions
the anions from 2,5-dihydrothiophen 1-oxide and 2,5-dihydrothiophen 1,l-dioxide
undergo ring-opening reactions and the resulting buta-1,3-dienylsulfenate and
buta-1,3- dienylsulfinate ions respectively may be alkylated. The anion from
2,5-dihydrothiophen also rearranges to the buta-1,3-dienylthiolate ion which
may be alkylated, but the overall reaction is incomplete and pure products
cannot be isolated; instead 1-(alkylthio)buta-1,3-dienes may conveniently be
prepared by base-catalysed ring-opening reactions of
1-alkyl-2,5-dihydrothiophenium salts. The 1-(alkylthio), 1-(alkylsulfinyl)- and
1-(alkylsulfonyl)buta-1,3-dienes isolated from the above reactions are very
unstable, and rapidly polymerize on standing at ambient temperatures.
The 9-decalyl and related cations. VI. Solvolysis of Pent-4-enyl p-nitrobenzenesulfonate in 1,1,1,3,3,3-Hexafluoropropan-2-ol and of 3-(Cyclohex-1'-enyl)propyl p-Nitrobenzenesulfonate in 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoropropan-2-ol
Authors: Ferber PH , Gream GE
Published: September 2010

Kinetic and product studies
have established that pent-4-enyl p-nitrobenzenesulfonate
undergoes insignificant solvolysis (1.5 %) by the π-route in 1,1,1,3,3,3-hexafluoropropan-2-ol. π-Participation to give the perhydroinden-3a-yl
(8-hydrindyl) cation during the solvolysis of 3-(cyclohex-1'-enyl)propylp-nitrobenzenesulfonate, a substituted
pent-4-enyl derivative, in fluorinated alcohols is, however, significant. In
buffered 2,2,2-trifluoroethanol, it occurs to the extent of 30%; in buffered
and unbuffered 1,1,1,3,3,3-hexafluoropropan-2-ol, the values are 96 and 98 %,
respectively.
Cyclopentanoids from phenol. VI. Chiral prostanoid intermediates
Authors: Gill M , Rickards RW
Published: September 2010

(4S)-4-(t-Butyldimethylsilyloxy)-3-chlorocyclopent-2-enone
(3a) is prepared from phenol in five steps including resolution of the initial
ring-contraction product, (1RS,4RS)-3,5,5-trichloro- 1,4-dihydroxycyclopent-2-ene-1-carboxylic
acid [(1) + (2)]. Conjugate addition-elimination reactions of functionalized
alkylmagnesiocuprate reagents with the synthon (3a) lead to 3-substituted (4s)-4-hydroxycyclopent-2-enone
derivatives, and thence by stereospecific transposition of the ring oxygen
functions to 2-substituted (4R)-4-hydroxycyclopent-2-enones. The efficiency and
versatility of the route are demonstrated by synthesis of the
(4R)-2-(6-methoxycarbonylhexyl)- and (4R)-2-(7-hydroxy-
heptyl)-4-hydroxycyclopent-2-enone derivatives, (5b) and (6b) respectively, which
are important intermediates in prostaglandin and prostanoid synthesis.
Structure of 5-Methyl-4-[(arylamino)methylene]-2,4-dihydro-3H-pyrazol-3-ones
Authors: Rockley JE , Summers LA
Published: September 2010

5-Methyl-4-[(arylamino)methylene]-2,4-dihydro-3H-pyrazol-3-ones have been synthesized.
Of the 12 possible tautomeric forms it has been shown that they exist as the
(ary1amino)methylene tautomerwith intramolecular
hydrogen bonding between the CO and exocyclic NH groups.
Crystal structure of 9-Oxofluorene-4-carboxylic acid
Authors: Kennard CHL , Smith G , Katekar GF
Published: September 2010

The crystal structure of
9-oxofluorene-4-carboxylic acid has been determined by direct methods using
three-dimensional X-ray diffraction data, and refined to R0·068 for 1323 'observed'
reflections. Crystals are monoclinic, space group P21/c with 24 in a
cell of dimensions a 3·843(3), b 7·986(5), c 3269(2) �, β 96·64(4)�.
The molecules form centrosymmetric hydrogen-bonded cyclic dimers
[O···O 2·642(3) �] with the plane of the carboxylic acid
making an angle of 26·5� with that of the 9-oxofluorene group. Stacks of
molecules form down the a axis with 3.843 �. separation.
The effect of side chain conformation on the carbon-13 substituent chemical shifts of N-substituted benzamides
Authors: Fong CW , Grant HG
Published: September 2010

The carbon-13 substituent
chemical shifts of the ipso and carbonyl atoms in the para-substituted series
Z-C6H4CONY2 (where Y = Me, Pri,
Ph) have been measured at low dilution in (D)chloroform, and dimethyl
sulfoxide. The DSP equation has been shown to hold for varying side chain
conformations with high precision when the same resonance substituent parameter
is used. Analysis of these data by the DSP equation indicates that the 'reverse
substituent chemical shift effect' for the carbonyl atom is substantially due
to a localized polarization of the π-electron system of the amide side
chain. The ratio of localized to extended π-polarization of the β
position of the amide side chain has been estimated. It is suggested that the
effective dielectric constant term for the transmission of field effects by the
cavity model varies with side chain conformation. The Cl
substituent shifts have been discussed in terms of the shift-charge ratio. A
variable-temperature study of the DSP parameters indicates an insignificant temperature
effect provided rotation around the benzene ring to amide side chain bond is
rapid.
Studies on intramolecular alkylation. XIII. The synthesis of 3,4-Dihydrophenanthren-2(1H)-ones from Pummerer intermediates
Authors: Blair IA , Mander LN , Mundill PHC
Published: September 2010

1-Methylsulfinyl-4-(naphthalen-1'-yl)butan-2-ones
(12)-(15) were rearranged and cyclized to the
1-methylthio-3,4-dihydrophenanthren- 2(1H)-ones (17)-(20), respectively, by
trifluoroacetic anhydride. Hydrogenolysis of (18)-(20) furnished the parent
ketones (9), (25) and (26). Evidence is provided to show the involvement of an
Ar1-5 route in the formation of (18) and (19), including the
formation of spiro ketone (23) from sulfoxides (14) and (16). Acid catalysed
cyclization of diazoketone (5) gave either phenanthren-3-one (8) or spiro
ketone (10) depending on the conditions employed.
The nitration of 2,4,5-Trimethylphenol, 3,4,6-Trimethyl-2-nitrophenol and their acetates
Authors: Hartshorn MP , Richards KE , Thompson RS , Vaughan J
Published: September 2010

Nitration with fuming
nitric acid of 2,4,5-trimethylphenol (1a), its acetate (1b), 3,4,6-trimethyl-2-nitrophenol
(2a) or its acetate (2b) gives the
3,4,6-trimethyl-2,4-dinitrocyclohexa-2,5-dienone (3) in high yield. Some
transformations of this dinitro ketone (3) are described.
A reinvestigation of the Prévost reaction with N-allylmorpholine
Authors: Cambie RC , Hayward RC , Jurlina JL , Rutledge PS , Woodgate PD
Published: September 2010

A reinvestigation of the Prevost reaction of N-allylmorpholine (1) with silver(I)
benzoate and iodine shows that it gives the 1,3-dibenzoate (2) (11%) through
rearrangement, the 1,2-dibenzoate (3) (5%) and (1) (13%).
N.M.R. studies of myelin basic protein. V. 1H N.M.R. of the peptides encephalitogenic in guinea pig
Authors: Margetson SA , Moore WJ , Gibbons WA
Published: September 2010

The 1H n.m.r.
spectra of the following peptides have been investigated: (1) the encephalitogenic
H-Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys-OH comprising
residues 114-122 of bovine myelin basic protein, (2) the corresponding -Arg-OH peptide of human basic protein, (3) the inactive
peptide in which D-Ala5 replaces L-Ala5. Measurements
were made in D2O solutions at 270 and 600 MHz over a range of
temperatures, concentrations and pH. All the proton resonances have been
assigned by comparisons with other peptide data, titration shifts, selective
decoupling and nuclear Overhauser effects, and data on the (α,α-
2H2)Gly7 nonapeptide. Ring current shifts and
their temperature dependence indicated that there is preferential stacking of
the Phe and Trp rings, and
also interactions between these rings and the Gln and
Lys residues near the C-terminus of the peptide.
These data suggest a reverse turn at the Gly4-Ala5
residues, a conformation that would be consistent with results from energy
calculations and biological activity. The n.m.r. spectra of the L-Ala and D-Ala
peptides differed in the temperature coefficients of certain chemical shifts,
including particularly those subject to ring current effects. Data in dimethyl
sulfoxide were limited by effects of aggregation, but definite conformation
differences compared to aqueous solutions were indicated.
γ-Irradiation of N-vinylpyrrolidin-2-one and its homopolymer
Authors: Davis JE , Senogles E
Published: September 2010

The effect of γ-radiation
on N-vinylpyrrolidin-2-one and its homopolymer, poly(N-vinylpyrrolidin-2-one),
has been investigated. With N-vinylpyrrolidin-2-one, polymerization occurs by a
radical mechanism and the presence of water has been shown to have a promoting
effect on the reaction, giving both increased polymerization rates and
molecular weights. This has been primarily attributed to an enhancement of N- vinylpyrrolidin-2-one
reactivity through hydrogen bonding. In contrast, irradiation of N-vinylpyrrolidin-2-one
in the presence of organic solvents leads to lower polymerization rates and
lower molecular weights than with the undiluted monomer. ��� Poly(N-vinylpyrrolidin-2-one) primarily
crosslinks on being irradiated. Gel fractions have been determined as a
function of radiation dose and the results shown to be consistent with the theoretical
data derived by Inokuti for a polymer with an initial molecular weight
distribution of the Schulz-Zimm type. This leads to values for the radiation
chemical yields of crosslinks and main chain scissions, G(X) and G(S), of
0.13�0.03 and 0.02�0.01, respectively, at 0°C.
Carbon-13 N.M.R. studies of 5α- and 5β-Cholestan-5-ols and analogous 8a-Methyl-trans- and cis-decahydronaphthalen-4a-ols
Authors: Coxon JM , Gibson JR
Published: September 2010

The carbon-13 n.m.r.
spectra of a series of C4- and C6-substituted 5α- and
5β-cholestan-5-ols and 8a-methyl-trans- and cis-decahydronaphthalen-4a-ols
are reported.
Vinylindenes and some heteroanalogues in the Diels-Alder reaction. VIII. 1-Benzyl-3-vinylindole as a diene
Authors: Lambert JD , Porter QN
Published: September 2010

1-Benzyl-3-vinylindole
gives stable adducts resulting from [2+4] cycloadditions with 1,4-benzo-quinone,
1,4-naphthoquinone, N- phenylmaleimide and maleic anhydride. Vicinal 1H
n.m.r. coupling constants for protons on the cyclohexene rings are used to show
that the first two adducts probably have half-chair conformations, while the
last have boat conformations. Non-equivalence of the benzyl methylene protons
of the benzoquinone adduct has been shown to display a surprising temperature
dependence. The adduct of the vinylindole and ethenetetracarbonitrile
is shown to be a cyclobutane resulting from a [2+2] cycloaddition.
Can 15N N.M.R. be used to determine the site of N-oxidation of Pyrimidine-2,4-diamine?
Authors: Cowden WB , Waring P
Published: September 2010

An investigation of the
products of N-oxidation of pyrimidine-2,4- diamine demonstrated that 15N
spectroscopy is an unreliable technique for the determination of the site of
N-oxidation. The 15N shifts caused by N-oxidation were small and
downfield and of no diagnostic value.
The viscosity of liquids at high pressures
Authors: Alexander DM
Published: September 2010

An equation is presented
which represents the variation of viscosity of a liquid with pressure in terms
of the compressibility (βT), thermal
expansion (α) and molar volume (V) of the liquid (∂In
η/∂P)T = βT+(Vα/2.45R)
The derivation of the
equation from an equation developed by Eyring and
coworkers is given and the application of the equation is shown to 17 liquids
for which data are available.
Volatility studies of metal chelates. V. Stability and volatility of transition metal chelates of tetradentate Schiff bases
Authors: Dilli S , Patsalides E
Published: September 2010

A
study of the effect of substituent groups on the thermal stability and
volatility of 15 tetradentate β-keto enamines and various copper(II),
nickel(II), palladium(II), cobalt(II), and oxovanadium(IV)
derivatives has been made by employing simultaneous thermogravimetry and
differential thermal analysis. The majority of these chelates are stable at
temperatures above 300°C although volatilities are significantly lower than for
the corresponding β-diketonates. Trends in the
volatilities of the copper(II), nickel(II), palladium(II) and oxovanadium(IV) chelates are rationalized in terms of substituent-group
effects on the polarity and intermolecular Lewis acid-base interactions. The
distinctive role of the metal ion in controlling chelate volatility is also discussed.
2,4-Di-O-methylgyrophoric acid and 2,4,5-tri-O-methylhiascic acid. New tridepsides from Parmelia damaziana
Authors: Elix JA , Jayanthi VK , Leznoff CC
Published: September 2010

The new tridepsides
2,4-di-O-methylgyrophoric acid (8) and 2,4,5-tri-O- methylhiascic
acid (5) in addition to the known metabolites atranorin (9), chloroatranorin
(10), ursolic acid (11), 5-O-methylhiascic acid (4) and gyrophoric acid (7)
have been isolated from the lichen Parmelia damaziana. The structure of the new
tridepsides has been established by total synthesis.
Pressure-dependent aquation of the Tris(2,2'-bipyridyl)iron(II) cation
Authors: Lawrance GA , Stranks DR , Sullivan TR
Published: September 2010

The aquation of Fe(bpy)32+ (bpy
= 2,2'-bipyridyl) was studied in aqueous hydrochloric acid at a range of
pressures between 1 and 2070 bar. Activation volumes (ΔV‡) in
1.0 M HCl (+ 12.3 cm3 mol-1),
0.01 M HCl (+14.8cm3 mol-1),
1.0 M DCl (+13.3 cm3 mol-1) and
0.01 M DCl (+16.3 cm3 mol-1)
were determined. A mechanism involving a significant positive contribution to
ΔV‡ arising from a low-spin ↔ high-spin preequilibrium
is proposed. The minor effect of the deuterium solvent isotope on ΔV‡ is
consistent with this proposal.
Thermodynamics of deuterium exchange reactions in water-amine and alcohol-amine systems
Authors: Kooner ZS , Fenby DV
Published: September 2010

Vapour pressures and molar
excess enthalpies at 298.15 K are reported for the systems H2O+(C2H5)2NH
and D2O+(C2H5)2NH. They are
analysed to give the equilibrium constant and enthalpy of the reaction ����������������� 2(C2H5)2NH(1)+D2O(1)→2(C2H5)2ND(1)+H2O(1)
Molar excess enthalpies at
298.15 K of the systems CH3OH+(C2H5)2NH,
CH3OD+(C2H5)2NH, C2H5OH+(C2H5)2NH
and C2H5OD+(C2H5)2NH are
used to obtain enthalpies of the reactions ���������� (C2H5)2NH(1)+ROD(1)→(C2H5)2ND(1)+ROH(1)� (R = CH3, C2H5)Thermodynamic properties of
various NH/OD exchange reactions are calculated from statistical mechanical
equations by use of harmonic frequencies.
Studies on gibberellin synthesis. The preparation of phenanthrenoid intermediates for the synthesis of gibberellin A21
Authors: Mander LN , Potter GJ , Pyne SG , Woolias M
Published: September 2010

Methyl
3-(6'-oxo-4'-methoxy-5',6',7',8'-tetrahydronaphthalen-1'-yl)propanoate
(11) was converted by conventional methods into diazoketone
(17) which underwent acid-promoted cyclization to dienone (18). Refunctionalization gave dienone (20) which was subjected
to a tandem alkylation, conjugate addition process with the sodium enolate of dimethyl malonate to
furnish a 2: 1 mixture of dimethyl (2RS,8aSR,10aSR)-2-methoxymethyloxy-10,12-dioxo-2,3,4,5,6,7,8a,9,10-decahydro-1 H-2,10a-ethano-
phenanthrene-8,8-dicarboxylate (21) and its 8a-epimer, respectively. Subsequent
manipulations led to lactone (26), but attempts to
convert this compound into a gibbane derivative were
unsuccessful.
Chemistry of the Coccoidea. VII. Synthesis of ceroalbolinic acid
Authors: Cameron DW , Conn C , Feutrill GI
Published: September 2010

The insect anthraquinone
ceroalbolinic acid (1) has been synthesized for the first time by successive Diels-Alder
addition of the highly functionalized dienes (6) and (9) to 2,6-dichloro-1,4-benzoquinone
The chemistry of Eremophila spp. XVI. New serrulatanes from Eremophila spp.
Authors: Croft KD , Ghisalberti EL , Jefferies PR , Proudfoot GM
Published: September 2010

Three new serrulatane diterpenes have been isolated from Eremophila species. Evidence is presented for the
structure of (15S)-7,8,16-trihydroxyserrulatan-19-oic acid, isolated as its
methyl ester from E. drummondii,
serrulat-14-ene-7,8,20-trio1 from E. linearis Chinnock and for (2S)-serrulat-14-ene-
2,7,8,20-tetraol from E. granitica.
Novel 1,5-Diepoxide rearrangements
Authors: Grant PK , Rowan DD
Published: September 2010

The epoxidic function of 8β,9β-epoxy-9,11-secopodocarp-11-ene
(1) was inert to lithium aluminium hydride but underwent extremely facile
intramolecular opening by a suitably placed nucleophile. The structure of the
cyclized products formed, some anomalous 1H n.m.r, chemical shifts
and the behaviour of the analogous 8,17-epoxy-14,15,16-trinorlabd-12-ene (14)
system are described.
The partitioning of the tetrahedral intermediate from the basic methanolysis of ethyl N-aryl-N-methylcarbamates
Authors: Broxton TJ , Deady LW , Lim RHK
Published: September 2010

The ratio of amine to
methyl carbamate from the title reaction provides information on the relative
nucleofugalities of some amines and the ethoxide anion, which is consistent
with previously postulated mechanisms for basic amide methanolysis.
Alkaloids of Tiliacora triandra
Authors: Wiriyachitra P , Phuriyakorn B
Published: September 2010

Three known alkaloids, tiliacorinine (1), tiliacorine
(2) and nortiliacorinine A (3), together with a new
alkaloid, tiliacorinine 2'-N-oxide (4), have been isolated from the roots of Tiliacora triandra
Diels (Menispermaceae).
Structural and spectroscopic studies of transition metal nitrite complexes. VII. Crystal structures and spectra of two dinuclear and trinuclear species with stoichiometry [Ni(methylpyridine)2(NO2)2] containing bridging nitrite groups
Authors: Finney AJ , Hitchman MA , Raston CL , Rowbottom GL , White AH
Published: September 2010

The crystal structures of
the dimer [Ni(γmpy)2(NO2)2]2,2C6H6
and the trimer [Ni(βmpy)2(NO2)2]3,-
C6Hs (γmpy = 4-methylpyridine,
βmpy = 3-methylpyridine) are reported, the
latter being the redetermination of a structure
described previously. The ligand coordination geometry in each oligomer is essentially octahedral, with neighbouring nickel(II) ions being bridged by two nitrite
groups, one through a single oxygen atom and the second through an oxygen and
the nitrogen atom. The amine ligands occupy trans coordination sites with the
terminal bond positions in both species being taken up by chelating nitrite
ions. In both compounds the oligomers pack so that
the amine rings form sheets with potential voids in the lattice being filled by
clathrated benzene molecules. The electronic spectra
of the complexes in the visible region are unusual, showing peaks centred at c. 17500 and c. 20500 cm-1, and the
assignment of these is discussed. The infrared stretching frequencies of the
nitrite groups in these and other compounds are found to correlate well with
the observed nitrogen-oxygen bond lengths.
Structural and spectroscopic studies of transition metal nitrite complexes. VIII. Crystal structures and spectra of three pentanuclear species with stoichiometry [Ni5(N-substituted ethane-1,2-diamine)4(OH)2(NO2)8]
Authors: Finney AJ , Hitchman MA , Raston CL , Rowbottom GL , White AH
Published: September 2010

The preparation of a series
of novel compounds of general formula [Ni5L4(NO2)8(OH)2]
formed by ethane-1,2-diamine or one of five N-substituted
ethane-1,2-diamines (L) is described. The crystal and molecular structures of
the ethane-1,2-diamine, N,N'-diethylethane-1,2-diamine
and N,N-dimethylethane-1,2-diamine
complexes are reported. Each compound contains a planar, pentameric
arrangement of nickel(II) ions, linked by bridging hydroxide and nitrite
ligands. The details of the nitrite bridges differ among the complexes, causing
differences in their electronic and infrared spectra. The structural variations
are probably caused by the differing steric requirements of the amine
substituents.
Chemistry of the Coccoidea. IX. Pigments from the lac insect Austrotachardia acaciae (Hemiptera) and associated synthetic work
Authors: Cameron DW , Feutrill GI , Karge RL , Patti AF
Published: September 2010

Minor pigments of the lacciferid Austrotachardia acaciae Maskell include isoerythrolaccin and the new 7-hydroxyerythrolaccin whose
structure was confirmed by synthesis. Severe treatment of certain derivatives
of 1,3-dihydroxyanthraquinone with aluminium chloride has resulted in novel deoxygenation to the 1-hydroxy series. The 1,2-dimethyl
anthraquinones, 3,6,8-trihydroxy-1,2-dimethylanthraquinone and
3,6,7,8-tetrahydroxy-1,2-dimethylanthraquinone, have been synthesized. Oxidation of the methyl
groups has been explored as a possible route to the synthesis of the major pigment
from A. acaciae,
xantholaccaic acid B.
Conformational analysis of coordination compounds. XIII. Complexes of 2-methylpentane-2,4-diamine
Authors: Hambley TW , Hawkins CJ , Palmer JA , Snow MR
Published: September 2010

The crystal structures of tetraammine{(�)-2-methylpentane-2,4-diamine} cobalt(III) tetrachlorozincate chloride and 2,2'-bipyridine{(�)-2-methylpentane-2,4-diamine)platinum(II)
nitrate semihydrate have been determined by X-ray
structure analysis. The former crystals are orthorhombic with the space group
P212121, with a 12.49, b 20.16 and c 7.68 �. The latter crystals are also
orthorhombic but with the space group Pbca with a 14.96, b 28.69 and c 19.45 �. Both structures have been refined by least-squares methods
to weighted R values of 0.034 (1407 reflections) and 0.055 (2301 reflections),
respectively. The six-membered diamine
chelate ring has a flattened chair conformation in
the cobalt complex, and an unsymmetric boat
conformation in the platinum complex. Strain-energy-minimization calculations
show these structures correspond to energy minima and the calculated
geometrical parameters are in good agreement with those observed for the chelate ring. Proton n.m.r. spectra are consistent with the
chair conformation being almost exclusively populated in the ammine complex and
in the tetracyanocobaltate(III) complex in aqueous
solution, but the and 13C n.m.r. spectra of the platinum(II) complex
show that, although the chair conformer predominates, the boat conformation is
significantly populated in solution.
Chemistry of pyrrolic compounds. XLVIII. The chemistry of porphyrins carrying sulfur-containing substituents at a meso-carbon
Authors: Clezy PS , Fookes CJR , Smythe GA
Published: September 2010

The preparation of a meso-thioacetoxyporphyrin by ring
synthesis from a dipyrrylthione is described together with the reaction of
thiocyanogen with octaethylporphyrin and coproporphyrin 11 to give meso-thiocyanatoporphyrins. Attempts to
produce meso-mercaptoporphyrins by
hydrolysis of either meso-thioacetoxy-
or meso-thiocyanato-porphyrins
failed. Instead the corresponding disulfides were produced and the properties
of this latter group are described.
Macrocyclic enol-ethers containing an acetylenic group from the red alga Phacelocarpus labillardieri
Authors: Kazlauskas R , Murphy PT , Wells RJ , Blackman AJ
Published: September 2010

Four new acetate-derived
metabolites have been isolated from two collections of the red alga Phacelocarpus labillardieri.
Three of these metabolites were 2,6-disubstituted pyran-4-ones containing a macrocyclic enol-ether ring. The
fourth compound was a 6-substituted pyran-2-one derivative.
Generalized van der Waals theory. IX. Excess properties of simple fluid mixtures
Authors: Nordholm S , Harrowell PR , Cheung K
Published: September 2010

The generalized van der Waals theory, recently
developed and applied to a wide range of problems involving simple single
component fluids, is here extended to uniform simple fluid mixtures. Binary
mixtures of hard spheres or particles interacting by Lennard-Jones
pair potentials are considered, the Lorentz-Berthelot
rules being used to generate the between-species pair-potential. The basic
theory is very simple, combining features of cell and mean field theories. Yet
it differs considerably from the presently favoured theories of mixtures. The
new GvdW theory is implemented at four levels of
sophistication but the calculations remain very simple by present standards
even for the most accurate form of the theory wherein the effective hard-sphere
diameters are determined variationally. The results
obtained for the equation of state and thermodynamic excess properties indicate
that the very favourable accuracy relative to the
simplicity of the theory observed for single component fluids is retained for
mixtures. In the case of excess properties calculations for a wide range of equimolar mixtures suggest that the GvdW
accuracy is substantially better than that obtained by random mixture or
average potential theories but not as good as that obtained by the best theories
based on the estimation of the radial distribution functions of the fluid.
Field desorption mass spectrometry of [6,6,7,12,13,13-hexamethyl-1,4,8,11-tetra-azacyclotetradeca- 7,11-diene]-nickel(II) and -copper(II) perchlorates
Authors: Roe SP , Cullis PG , Derrick PJ , Hill JO
Published: September 2010

Field desorption mass
spectrometry has been used to characterize the title complexes. The mass
spectra indicate the presence of 'cluster ions' involving the macrocyclic
cation hydrogen-bonded to perchlorate and water, and the absence of fragment
ions of both the cationic and anionic species. The unique features of this
investigation are the simplicity of the mass spectra and the ease of analysis
of perchlorate compounds.
Oct-1-en-3-ol and (5Z)-Octa-1,5-dien-3-ol, compounds important in the flavour of prawns and sand-lobsters
Authors: Whitfield FB , Freeman DJ , Last JH , Bannister PA , Kennett BH
Published: September 2010

Two volatile compounds
isolated from seven species of prawns and one species of sand-lobster have been
shown by g.l.c., micro-reaction g.l.c., n.m.r., mass spectrometry and synthesis
to be oct-1-en-3-ol (2) and (5Z)-octa-1,5-dien-3-ol
(3). These alcohols, which have respectively a mushroom-metallic and a metallic
flavour in dilute aqueous solutions, impart a metallic flavour when added to
the flesh of crustaceans.
Formation of iodides and esters from alcohols and tributyldiiodophosphorane and diiodotriphenylphosphorane
Authors: Haynes RK , Holden M
Published: September 2010

Tributyldiiodophosphorane and
diiodotriphenylphosphorane, prepared in
situ from the corresponding phosphine and iodine, are generally able to
convert primary and secondary alcohols into iodides at room temperature in
diethyl ether or benzene containing two equivalents of hexamethylphosphoric
triamide. Tertiary alcohols, as gauged by the lack of reactivity of t-butyl
alcohol, are, however, inert to these iodinating agents. 6-Hydroxyhexanoic acid
yields a mixture of 6-iodohexanoic acid and 7-heptanolide. The first reagent
also promotes facile condensation of secondary and tertiary alcohols with
carboxylic acids to form hindered esters in good yields. The phosphorane
derived from tris-(dimethy1amino)phosphine and iodine, while less effective as
an iodinating agent, rapidly converts 6-hydroxyhexanoic acid into 6-iodo-N,N-dimethylhexanamide, and hexanoic and
benzoic acids into the corresponding N,N-dimethylamides
in excellent yields at room temperature. Treatment of 3β- tosyloxycholest-5-ene
with lithium iodide yields 3β-iodocholest-5-ene, and not 3α-iodocholest-5-ene,
as previously reported.
Kerr constants and conformations of some p-substituted benzaldehydes
Authors: Mirarchi D , Ritchie GLD , Williams AJ
Published: September 2010

Analysis of the
experimental infinite-dilution molar Kerr constants of five p-substituted benzaldehydes
(X-C6H4-CHO; X = NO2, CN, F, Cl, Br) as
solutes in carbon tetrachloride at 298 K confirms that uniplanar
molecular conformations are preferred.
Photochemistry of heterocyclics. III. Photolysis of various 2-substituted benzimidazoles
Authors: Crank G , Mursyidi A
Published: September 2010

A variety of 2-substituted
benzimidazoles have been irradiated with ultraviolet light to determine the
effects of substituents on the photochemical behaviour of the benzimidazole
ring system. Benzimidazol-2-amine gave [2,5'-bibenzimidazol]-2'-amine and [2,4'-bibenzimidazol]-2'-amine,
showing that this derivative behaves in the same way as benzimidazole.
2-Chlorobenzimidazole loses chlorine forming a dimeric species and
benzimidazol-2(3H)-one, which is itself inert to photolysis.
2-Trichloromethylbenzimidazole also loses chlorine to form a variety of
products depending on the solvent. 2-Trifluoromethylbenzimidazole
does not lose fluorine but forms a dimer and also undergoes imidazole ring
cleavage. Benzimidazole-2-thiol also undergoes imidazole ring cleavage with
loss of sulfur. The 2-phenyl group stabilizes the benzimidazole ring system to
photolysis as does the 2-thiazolyl group; however, the latter suffers thiazole
ring cleavage.
Pyrimidine N-oxides. IV. The N,N'-dihydroxy derivatives of phenobarbital and veronal
Authors: Cowden W , Jacobsen NW
Published: September 2010

5-Ethyl-1,3-dihydroxy-5-phenylbarbituric
acid (N,N'-dihydroxyphenobarbital)
and 5,5-diethyl-1,3-dihydroxybarbituric acid (N,N'-dihydroxyveronal) have been prepared
by the condensation of 1,3-dibenzyloxyurea with ethylphenylmalonyl
dichloride and diethylmalonyl dichloride
respectively, followed by the removal of the benzyl protecting groups from the
intermediate dibenzyloxy derivatives.
Deoxygenation of 1,4-epoxy- 1,4-dihydroarenes with enneacarbonyldiiron
Authors: Best WM , Collins PA , McCulloch RK , Wege D
Published: September 2010

1,4-Epoxy-1,4-dihydroarenes
are converted
in high yields into the corresponding arenes with enneacarbonyldiiron
in refluxing benzene solution.
Carbonyl halides of the Group VI transition metals. XXVII. Carbon-13 N.M.R. studies on molybdenum compounds
Authors: Colton R , Kevekordes J
Published: September 2010

Carbon-13 nuclear magnetic
resonance studies have been carried out on a number of molybdenum(II) carbonyl
halide species. It has been found that for these seven-coordinate capped
octahedral complexes there is a very large shift to high frequency for a carbonyl
group in the capping position. Thus carbon-13 n.m.r. provides a useful tool to
distinguish between possible isomers. Trends in stability and isomer formation
previously suspected from circumstantial evidence can now be rationalized.
Support effects on iron(III) oxide catalyst in the reduction of nitrogen oxide with hydrogen
Authors: Iizuka T , Ikeda H , Terao T , Tanabe K
Published: September 2010

Catalytic reduction of NO
with H2 has been carried out over Fe2O3
dispersed on ten kinds of supports. Among the carrier oxides, Fe2O3
on SiO2 was the most effective catalyst and Fe2O3
on SnO2 was least active. The surface states and adsorption states
of NO on supported Fe2O2 were studied by means of i.r. and M�ssbauer spectroscopies. The intensities of the i.r.
bands at 1810 and 1735 cm-1 of the adsorbed NO on reduced iron sites
are discussed in connection with the catalytic activity.
Mutarotation of D(+)-glucose. I. Evidence of electrophilic attack by hydrated monomeric and dimeric copper(II) species
Authors: O'Conner CJ , Odell AL , Bailey AAT
Published: September 2010

The rate of mutarotation of α-D(+)-glucose is markedly affected by
the addition of electrolytes. At 293 K the rate constants for reaction with H2O,
HClO4, NaClO4 and CU(ClO4)2 are 4.6
× 10-6, 5.9 × 10-3,1.2 × 10-4 and 4.6 × 10-3
dm3 mol-1 s-1 respectively. In the pH range
3.5 - 4.4 the rate of mutarotation increases sharply
in solutions of Cu(ClO4)2 because of the presence of
small concentrations of Cu((OH)2CU)2+ for reaction with
which the second-order rate constant is 4.0 dm3 mol-1 s-1.
A model for mutarotation is proposed which involves a
specifically oriented aquation sheath about the
charged ion which then acts as an enhanced electrophile
in the rate-determining step to form the aldehyde intermediate. In the presence
of mixed cationic catalysts, additivity rather than
competition is observed between the effect of two catalysts. This result and
the observed increase in the entropy of activation in the presence of aquated copper(II) support this model.
Substitution reactions of nitrothiophens. V. Isolation and reactions of the exocyclic methylene intermediates in SN(AEAE) reactions
Authors: Newcombe PJ , Norris RK
Published: September 2010

The reaction of lithium
2-nitropropan-2-ide(1)with 2-(1'-chloro-2',2'-dimethylpropyl)-4-nitrothiophen
(5) gives a complex mixture of products, including the salt (15), nitro
compounds (17a-c)and oximes (18) and (19). The formation of these products can
be rationalized in terms of initial formation of 5-[(Z)-2',2'-dimethylpropylidene]-2-(1''-methyl-1''-nitroethyl)-3-nitro-2,5-dihydrothiophen
(16) whose analogues have been proposed as reactive intermediates in the SN(AEAE)
reaction. The diene (16), which is a stable
isolable compound [tautomeric with the thiophen (27)], reacts with the salt (1)
to give the above products and with sodium p-toluenesulfinate
to give the sulfone(32). The analogous chloride (6)
and the acetate (7) react in a similar fashion and give the diene (21), which
also reacts in part in an SN(AEAE) reaction to give the substitution
product (23).
Carbonyl and thiocarbonyl compounds. XIX. Intramolecular cyclization of (2-nitroetheny1)aryl N-arylcarbamates : synthesis of newer series of 3,4-dihydro-2H-1,3-oxazin-2-ones and their antimicrobial activities
Authors: Latif N , Mishriky N , Assad FM
Published: September 2010

The
hitherto unknown 2-(2-nitroethenyl)aryl and 1-(2-nitroethenyl)naphthalen-2-yl N-arylcarbamates (2) and (5) are readily
obtained through the uncatalysed interaction of aryl isocyanates with the corresponding
2-nitroethenyl phenols (1) and (4). The carbamates (2) and (5) cyclize readily
at ambient temperature under base catalysis to the corresponding
3-aryl-4-nitromethyl-3,4-dihydro-2H-1,3-benzoxazin-2-ones (3) and 2-aryl-1-nitromethyl-2,3-dihydro-1H-naphth[l,2-e][1,3]oxazin-3-ones
(6). The
oxazinones (3) are cleaved by hot pyridine affording the corresponding
2-(2-nitroethenyl)phenols and N,N'-diarylurea,
whereas, with butylamine, the corresponding aryl(butyl)urea and salicylaldehyde
are obtained. The antimicrobial properties of the carbamates and benzoxazinones
are evaluated.
Model calculations of isotope effects. VI. The structure of the transition state for hydrogen atom transfer from ethane to methyl radicals
Authors: McLennan DJ
Published: September 2010

Kinetic hydrogen isotope
effects for the reaction
C2H6 + CDB → C2H5
+ CHD3
have been calculated for a
large number of transition state models, bond orders being based on an ab initio
structure for the ethyl radical. Various empirical relationships for transition
state force fields in terms of partial bond orders were examined for each model
structure. No transition state model reproduced the experimental intermolecular
and intramolecular isotope effects over the
temperature range, but when an Eckart tunnel
correction was applied a single model gave satisfactory agreement.
Depsidone synthesis. XXIII. The oxidation of 2,2'-dihydroxy-4,4'-dimethoxy-6,6'-dimethylbenzophenone
Authors: Sala T , Sargent MV , Skelton BW , White AH
Published: September 2010

Oxidation
of 2,2'-dihydroxy-4,4'-dimethoxy-6,6'-dimethylbenzophenone
(1) with alkaline ferricyanide gave
the expected 4',6-dimethoxy-4,6'-dimethylspiro[benzofuran-2(3H),1'-cyclohexa-3',5'-diene]-2',3(2H)-dione (2) as well as 2'-hydroxy-6-methoxy-4,5'-dimethylspiro[benzofuran-2(3H),1'-cyclopent-4'-ene]-3(2H),3'-dione
(3). The structure of compound (3) was
deduced from its spectroscopic properties and was confirmed by X-ray
diffraction.
The anodic oxidation of silver in sulfide solutions
Authors: Campbell GD , Lincoln FJ , Power GP , Ritchie IM
Published: September 2010

This work extends a
previous study on the electrochemistry of silver electrodes in aqueous sulfide
solutions. It has been found that the voltammograms
for the silver-sulfide system have additional features to those reported
earlier. The nature and interpretation of the additional features is described.
Peaks due to silver oxides, and chemically formed silver sulfide, are
identified and discussed. Further evidence for the presence of α- and β-Ag2S
in the layer deposited during anodic oxidation of the silver was obtained from
chronopotentiometric and diffraction studies.
Outer-sphere electron-transfer reactions of ascorbate anions
Authors: Williams NH , Yandell JK
Published: September 2010

Rate
constants for the one-electron oxidation of ascorbate
dianion (A2-) by bis(terpyridine)cobalt(III)ion (8.5 × 106 dm3
mol-1 s-1) and pentaammine(pyridine)ruthenium(III) ion (6.0 × 109
dm3 mol-1 s-1), and of the monoanion
(HA-) by tetraammine (bipyridine)ruthenium(III)ion
(2.1 × 105 dm3 mol-1s-1) have been
determined in aqueous solution at 25�C and ionic strength 0.1
(NaNO3 or NaClO4). It is shown that these rate constants,
and other published rate constants for oxidation of HA- and A2-,
are consistent with the Marcus cross relation, on the assumption that the self-exchange
rate constants for both the HA-/HA and A2-/A-couples
are 106 dm3 mol-1 s-1. One electron
redox potentials for the ascorbate/dehydroascorbate system have been derived
from scattered literature data.
Lactonization of o-Arylethenylbenzoic acids: Formation of 3,4-dihydro- 1 H-2-benzopyran-1-ones and isobenzofuran- 1(3H)-ones
Authors: Teitei T
Published: September 2010

The formation of six
3,4-dihydro-1H-2-benzopyran-1-ones (2a-f) and one isobenzofuran-1(3H)-one
(3a) from o-arylethenylbenzoic
acids (1) in neutral or acid solution is described. The benzoic acids having a
neutral or electron-releasing group on the double bond give δ-lactones
(2), whereas compounds with a strong electron-withdrawing group give the γ-lactones
(3). The mechanism is discussed in terms of electronic effects. The rate of
cyclization of the (Z)-compound is found to be faster than that of the
(E)-compound.
Defensive alkaloids of Cryptolaemus montrouzieri (Coleoptera : Coccinellidae)
Authors: Brown WV , Moore BP
Published: September 2010

The
chemical defensive system of the ladybird Cryptolaemus montrouzieri consists mainly of three related alkaloids. Two of these have
been identified as cis-1-(6-methyl-2-piperidyl)propan-2-one (3) and
1-methyl-9-azabicyclo[3,3,1]nonan-3-one (2);
the third is very unstable and readily isomerizes to (3).
Intermediate-stage transition metal ion exchange in a zeolite X
Authors: Chatterjee M , Ganguli D
Published: September 2010

The exchange behaviour of
some divalent transition metal ions M2+ (Zn2+, Cu2+,
Ni2+, Co2+, Mn2+) in a zeolite
NaX (SiO2/Al2O3
2.75) was studied at intermediate stages before equilibrium. The equivalent
counter ion supply in the solution, given by the equivalent ratio of the two
counter ions 2M2+/Na+, was found to be critical in
determining the saturation level of exchange. The series of relative abilities
of exchange was very similar to the well known selectivity series at
equilibrium. It is suggested that water exchange of the metal ions in solution
could be one of the factors controlling the relative ease of ion exchange.