bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalysis by hydrogen halides in the gas phase. XI. Tertiary butyl ethyl ether and hydrogen chloride
Authors: Stimson VR , Watson EJ
Published: September 2010

Hydrogen chloride catalyses the
decomposition of t-butyl ethyl ether at 320-428�. Isobutene is quantitatively
the product and the kinetic form is first order in the ether and in hydrogen
chloride. The Arrhenius equation:��������� k, = 1012'16exp( -30,60O/RT) (sec-l ml mole-=)

is followed. The mechanism
of the reaction seems similar to those of other hydrogen halide catalysed
decompositions of ethers and alcohols.
Fluorescence spectrum of phenanthrene single crystal at 4°K
Authors: Misra TN , Lacey AR , Lyons LE
Published: September 2010

The fluorescence spectrum of
anthracene-free phenanthrene single crystals at 4�K has been investigated. The
whole spectrum has been analysed in terms of three superimposed spectra, one
(weak) originating in a free pure exciton level of the pure phenanthrene
crystal and two associated with defects. One of the defect spectra is very
strong. All three series can be analysed in terms of similar if not identical
vibrational frequencies.
Synthetic studies in the 1,2-dithiole series. IV. The methylation of 4-Benzamido-1,2-dithiole-3-thione
Authors: Brown RFC , Rae ID , Shannon JS , Sternhell S , Swan JM
Published: September 2010

The product of methylation of
4-benzamido-1,2-dithiole-3-thione has been shown to be methyl
5-methylthio-2-phenyloxazole-4-carboditloate (Ib) rather than
4-bis(methylthio)-methylene-2-phenyl-2-oxazoline5-thione (Ia) as previously
reported.
Coordination compounds of Group IB metals. IV. Triethyl- and triphenyl-phosphine complexes of aurous alkyl xanthates
Authors: Kowala C , Swan JM
Published: September 2010

The preparation of new compounds in the
series Et3PAuSC(S)OR (R = Me, Pr, Pr1, Bu, Bus, pentyl) and Ph3PAuSC(S)OR
(R = Me, Et, Pr, Pr1) is described. The
compound (Ph3P)2AgSC(S)OEt
was also prepared.
The aluminium chloride catalysed reaction of phosphorus(III) halides and carbonyl compounds. I. Reaction with benzophenone
Authors: Freeman KL , Gallagher MJ
Published: September 2010

In the presence of
partially hydrated aluminium chloride, phenylphosphonous
dichloride and diphenylphosphinous chloride add smoothly to benzophenone to
give chlorodiphenylmethylphenylphosphinic chloride
and benzhydryldiphenylphosphine oxide respectively. Little
reaction occurs with anhydrous aluminium chloride, and phosphorus trichloride
does not react under any conditions. The factors affecting these reactions are
described and possible mechanisms discussed. It is suggested that the
intermediacy of species of the type [PhPCl3]+[PhPCl,AlCl3]- best explains the
observed results.
Wilzbach Tritation studies. III. A study of physical variables affecting exchange in the polycyclic aromatics
Authors: Garnett JL , Law SW
Published: September 2010

The effect of particle size
of substrate and tritium gas pressure on the efficiency of Wilzbach tritiation
of crystalline polycyclic hydrocarbons has been investigated.

The hydrocarbons studied included
naphthalene, biphenyl, phenanthrene, chrysene, pyrene, m- and p-terphenyls, and
acridine. No simple relationship between ionization potential and tritium
incorporation was observed. The effect of radical scavengers such as nitric
oxide and moderators such as helium on the labelling process have been examined.

Tritium incorporation in a polycyclic
hydrocarbon is enhanced lf gas exposure occurs in the presence of benzoic acid.
The results are discussed in terms of current theories proposed for tritium
labelling based on gas-phase studies. In the condensed phase present data show
that radical processes are important in Wilzbach labelling. This has been
confirmed by a preliminary e.s.r. examination of naphthalene and anthracene in
the presence of tritium gas.
Coordination complexes of amino acids: Preparation and properties of some copper(II) and copper(I) complexes containing mixed bidentate ligands
Authors: Laurie SH
Published: September 2010

Complexes of copper(II) of
the type [CuAB] have been synthesized in which A is
the anion of acetylacetone, salicylaldehyde, 8- hydroxyquinoline,
or diethyl-dithiocarbamate, and B is the anion of phenylalanine, tryptophan, or
tyrosine. Examination of their spectral, magnetic, and solubility behaviour
established them to be normal, molecular, copper(II) complexes.

Bis(2,9-dimethylphenanthroline)copper(I)
amino-acidates were also prepared. Their spectra suggest that, in solution at
least, no coordination of the amino acid to the copper(I) occurs.

Preliminary irradiation experiments, at
3080 Ǻ, show that photo- reduction to copper(I) occurs in dimethylformamide
solutions; the copper(I) complexes remained unchanged under the same
conditions.
Further observations on the occurrence of metastable phases during thermal decomposition of sulphates
Authors: Bear IJ
Published: September 2010

Observations of the
occurrence of metastable phases in the BeSO4-H2O
system have substantiated
earlier findings relating to the Zr(SO4)2-H2O
system. The results have provided
further evidence that the formation of polymorphic compounds during thermal decomposition
processes is controlled by the vapour pressure of the volatile component in the
relevant region of the particular phase system.
The reaction of tervalent phosphorus compounds with dichlorodiphenylmethane
Authors: Freeman KL , Gallagher MJ
Published: September 2010

The reactions of dichlorodiphenylmethane with (MeO)3P,
(MeO)2PPh,

MeOPPh2, PPh3, Bun3P, (Me2N)3P,
and Ph3As have been studied, and the
origin of the products is discussed in terms of attack of phosphorus at halogen
and carbon. Attack at halogen does not seem
to be the initial step in these reactions.
The stereochemistry of oxindole alkaloids: uncarines A, B (formosanine), C (pteropodine), D (speciophylline), E (isopteropodine), and F
Authors: Beecham AF , Hart NK , Johns SR , Lamberton JA
Published: September 2010

A study of the N.M.R.
spectra, circular dichroism, and equilibration reactions of the four stereoisomeric oxindole
alkaloids, uncarines C (pteropodine),
D (speciophylline), E (isopteropodine),
and F, isolated from Ulzcaria berlzaysii F.
Muell, and Uncaria ferrea D.C., has allowed assignment of the configuration
at all five asymmetric centres. Partial synthesis of uncarines
C, D, E, and F from tetrahydroalstonine has provided
proof for the assigned stereochemistry of the rings D and E. Comparison of the spectra
of uncarines C, D, E, and F, mitraphylline,
and isomitraphylline with those of formosanine (uncarine B) has
shown that in formosanine and uncarine
A the D/E ring junction is trans, and
not cis, as previously reported.

Formosanine and uncarine A are therefore
the C19 epimers of mitraphylline
and isomitraphylline respectively.
Energetic considerations in the assignment of some fragment ion structures
Authors: Occolowitz JL , White GL
Published: September 2010

Based on energetic
considerations, new structures are presented for fragment ions from phenol,
aniline, the naphthols, and coumarin.
Previously proposed structures are shown to be inconsistent with the energetics of formation of the ions. Some deficiencies in the
methods of assigning structures to fragment ions both by comparison with the
mass spectra of related compounds and by consideration of the reactions of
metastable ions of the same composition are discussed.
Carbonyl halides of the Group 6 transition metals. VI. Complexes with Bis(diphenylphosphino)methane
Authors: Anker MW , Colton R , Tomkins IB
Published: September 2010

Complexes of the type MX2(CO)2
diphos2 [M = Mo, W; X = Cl, Br;

diphos = bis(diphenylphosphino)methane]
have been prepared and characterized. The
complexes are neutral, diamagnetic, seven-coordinate species with one of the diphosphine molecules acting as a monodentate ligand.
Nuclear magnetic resonance, conductance, and molecular weight studies support
this view. The monomeric complex MoBr2(CO)3
diphos has also been prepared.
Carbonyl halides of the Group VI transition metals. VIII. Paramagnetic and diamagnetic dicarbonyl derivatives of molybdenum(II)
Authors: Colton R , Rix CJ
Published: September 2010

Complexes of the general
formula Mo(CO)2L2X2 (L = pyridine (py), 2,2'-

dipyridyl (dipy), 1,l0-phenanthroline
(phen); X = Cl, Br) have been isolated. The pyrldine
derivatives are yellow monomeric compounds which are paramagnetic, but the
complexes with dipy and phen contain diamagnetic
seven-coordinate cations and are correctly formulated as [Mo(CO)2L2X]+X-.
Conductance, infrared, magnetic, and electron spin resonance studies have been
carried out.
The molar Kerr constants, apparent dipole moments, etc., of alkyl nitrites as solutes
Authors: Le FRJW , Pierens RK , Radford DV , Steel KD
Published: September 2010

The apparent dipole moments
of ten, and the apparent molar Kerr constants of seven, alkyl nitrites as
solutes in carbon tetrachloride at 25� are recorded and discussed in terms of
assumptions that the dissolved species are either (a) mixtures of two planar
forms in which the R-O and K=O bonds have an s-cis : s-trans relationship,
or (b) mixtures of many
non-planar rotamers, definable by angles of twist 4
between the planes containing the R-O and S=O units. On basis (b) the observed
properties are average values, theoretically predictable only when potential
energies as functions of � become known. "Effective" conformations
for MeO-N=O and Me3CO-N=O
having � values of 98� and 146.5� can be inferred from the ∞(mK2) values found for these esters.
Nitrones and oxazirans. IV. Attempted intramolecular cycloaddition of unsaturated 1-pyrroline 1-oxides; pyrolysis of these compounds and their related oxazirans
Authors: Bapat JB , Black DS
Published: September 2010

The possibility of thermal
or photochemical intramolecular cycloaddition processes is discussed, but no
evidence for such reactions was found in the compounds investigated. The pyrolysis of some
2-phenyl- and 2-styryl-substituted 1-pyrroline 1-oxides results in the formation of the related pyrrolines. The same products are generally observed in the
similar pyrolytic decomposition of the isomeric oxazirans.
Isothiazole chemistry. V. Acylation and acyl migration in 3-hydroxyisothiazole
Authors: Chan AWK , Crow WD
Published: September 2010

In aprotic solvents acylation of 3-hydroxyisothiazole
is subject to kinetic control, leading almost exclusively to the 3-acyloxyisothiazoles. On heating or standing a reversible O
→ N migration occurs, the final composition of the mixture depending on
the nature of the acyl group. Where aliphatic acyl groups are involved (RCO: R = CH3, C2H5,
C3H7, ClCH2, CH3O,
C2H5O) the tendency towards migration to nitrogen is
inversely related to the size of the group, whereas with aromatic groups (R = C6H5,
4-MeC6H4, 4-NO2C6H5,
3,5-(NO2)2C6H3, C6H5CH2),
little or no N-acyl derivative results. Sulphonyl halides lead only to
0-sulphonyl derivatives, which presumably do not rearrange. The migration of the acyl
group is shown to be intermolecular, involving both O + O and O → N
migration, by the usual mixed migration experiments, and is catalysed by 3-hydroxyisothiazole and other nucleophiles. The greater
thermodynamic stability of the O- or ,N-acyl derivatives, as revealed by
equilibrium measurements, is seen to be a function of the steric requirements
of the acyl group, the larger groups being more stable on oxygen. Examination
of the infrared spectra reveals that this
is probably due to out-of-plane twisting in the N-acyl-3- isothiazolones,
which prevents N-CO overlap in all derivatives except the formyl
which exists as 100% N-formyl at equilibrium.
4,5-Seco-4,6-cyclosteroids. III. Observations on the course of reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol
Authors: Collins DJ , Hobbs JJ , Rawson RJ
Published: September 2010

It has been shown that
reductive rearrangement of 6β-bromo-4β,5-epoxy- 5β-cholestan-3β-ol
(I) to 4,5-seco-4,6-cycle-6β-cholestane-3β,5α-diol (IXa) with
lithium aluminium hydride in tetrahydrofuran proceeds via
6β-bromo-5β-cholestane-3β,5-diol (IIa). Relevant reactions of
the latter and the corresponding 3-ketone are discussed. ��� Similar conversion of the 3-epimer of (I)
into 4,5-seco-4,6-cyclo- 6β-cholestane-3α,5α-diol (XIIIa) in
high yield indicates that reductive rearrangement of the 6β-bromo-5β-hydroxy
moiety proceeds without participation of the 3-aluminate complex. Some
derivatives of (XIIIa) are described. ��� Experimental conditions required for the
conversion of (I) into (IXa) are defined. ��� Combined evidence indicates that the
reaction proceeds in a concerted manner by essentially base-catalysed,
1,3-elimination of hydrogen bromide from diol (IIa) with 4,5-bond migration to
give the formal intermediate 3β-hydroxy-4,5-seco-4,6-cyclo-6β-cholestan-5-one
(VI), further reduced to (IXa).
2-Substituted and 2,6-disubstituted 1,4-benzoquinone 4-oximes ('p-nitrosophenols')
Authors: Norris RK , Sternhell S
Published: September 2010

The preparation and
physical properties of 27 compounds in the title series are described.
Tautomerism, syn-anti isomerism, N.M.R. parameters,
and the mechanism of isomerization are discussed. In this series of
derivatives, the tautomeric equilibrium in dioxan solutions lies heavily
towards the oxime form unless intramolecular hydrogen bonding between the
substituent at C2 (or C6) and the phenolic hydroxyl group of the nitroso form
is possible. The substituents at C2 (and C6) influence the position of the syn-anti equilibrium in the quinone monoxime forms through
electronic effects.
Bromination of p-bromophenol. II. Catalysis by iodine and anhydrous aluminium chloride
Authors: Rajaram J , Kuriacose JC
Published: September 2010

The phenomenon of catalytic
maximum has been investigated in the bromination of p-bromophenol (ArH) using
iodine and anhydrous aluminium chloride as catalysts. The effective catalysts
have been shown to be iodine bromide in acetic acid and carbon tetrachloride
media, and AlCl3,Br2 in acetic acid. A correlation
between the ratio of the reactants at the catalytic maximum, and the order in
the effective catalyst has been deduced and experimentally verified.
Skeletal-rearrangement fragments in the mass spectra of β-thiopropionic acid derivatives
Authors: Bowie JH , Cobb DB , Dalgaard L , Madsen JO , Lawesson S
Published: September 2010

The mass spectra of
S-alkyl-β-thiopropionic acids contain skeletal- rearrangement ions which
arise by hydroxyl migration to a carbonium-ion centre followed by elimination
of a neutral molecule (e.g. ketene or formaldehyde). In contrast, those of
methyl S-alkyl-β-thiopropionates contain peaks which are formed by
methoxyl migration to sulphur, followed by loss of ketene.
Carbony1 halides of the Group VI transition metals. XV. Complexes with Bis(1,2-diphenylphosphino)ethane
Authors: Anker MW , Colton R , Rix CJ , Tomkins IB
Published: September 2010

Compounds of the general
formulae M(CO)3(dpe)X2, [M(CO)2(dpe)1.5X2]2,
and M(CO)2(dpe)2X2 have been prepared and
characterized (M = Mo, W; dpe = bis- (1,2-diphenylphosphino)ethane; X = Cl, Br,
I). All of the compounds are diamagnetic and most of them are non-electrolytes.
However, conductivity measurements indicate that, for the iodo derivatives
only, the bis(dpe) compounds should be formulated as 1 : 1 electrolytes, [M(CO)2(dpe)2I]I.
��� For the iodo series of compounds only,
there is a complex series of reversible reactions including a new type of
carbon monoxide carrying system. In addition, the dimeric dpe derivatives are
cleaved by carbon monoxide at room temperature and pressure to give equal
quantities of [M(CO)2(dpe)2I]I and M(CO)3(dpe)I2.
Phosphonium salts. II. The reaction of bis-phosphonium salts with metal hydrides
Authors: Brophy JJ , Gallagher MJ
Published: September 2010

Ethane-1,2-bis-phosphonium
salts are cleaved by sodium hydride to phos- phines in 55-80% yields with loss of the two-carbon bridge.
The reaction is independent of the substituents at the phosphorus atoms. The
same reaction is observed with an ethene-1,2-bis-salt and with but- 2-ene-1,4-bis(triphenylphosphonium)
dibromide. It is suggested that a phosphorane is formed which subsequently fragments
in a manner analogous to alkaline hydrolysis. ��� Lithium aluminium .hydride behaves
similarly but loss of the bridge is competitive with loss of benzyl groups, and
yields are generally better (> 70%).
The synthesis and properties of several annelated 1,5-Di-trans-[10]annulenes
Authors: Bindra AP , Elix JA , Sargent MV
Published: September 2010

Di-trans-1,2:3,4-dibenzo[7,8-c]furo[10]annulene
(VI) and di-trans- 1,2:3,4-dibenzo-7,8-(3?,6?-epoxy-4?,5?-
dimethoxycarbonyl)cyclo- hexeno[10]annulene (VII) have been synthesized. As a
result of the steric interference of the internal hydrogen atoms, the former
compound could be separated into two conformational isomers. Neither (VI) nor
(VII) possessed a delocalized ten π-electron system.
The dibenzylidene derivative of glucose phenylosotriazole
Authors: Brecknell DJ , Carman RM
Published: September 2010

The dibenzylidene
derivative (m.p. 141�) of D-glucose phenylosotriazole is shown by degradative
and p.m.r. evidence to have a 3,4:5,6-di-O- benzylidene structure with two
five-membered dioxolan rings. The compound has the R configuration at both
acetal carbon atoms.
Kinetic medium effects. IV. Hydrolysis of trimethyl phosphate in mixed solvents
Authors: McTigue PT , Renowden PV
Published: September 2010

The rate of hydrolysis of
trimethyl phosphate (tmp) has been measured at 90.5�
as a function of solvent composition in water-dimethyl sulphoxide
and water-ethylene glycol mixtures. The rate constant of the
"spontaneous" hydrolysis decreases with decreasing water content; an
acid-catalysed reaction, whose rate constant increases with decreasing water
content, becomes dominant at low water concentrations. Solvent isotope effects
in D2O have been measured for both the spontaneous and acid-catalysed
reactions, and are close to unity in each case. Salt effects have also been
studied In aqueous sodium nitrate and perchlorate solutions, and are found to
be small. Reaction mechanisms are discussed in the light of the results
obtained.
Volumes of mixing and viscosities of liquid mixtures of ketones and o-chlorophenol
Authors: Naidu PR
Published: September 2010

Volumes of mixing and
viscosities of o-chlorophenol in ethyl methyl ketone, methyl propyl ketone,
diethyl ketone, and isobutyl methyl ketone have been determined at 30.0�.
Volumes of mixing have been examined on the basis of electron-donating
capacities of the ketones. Viscosities of the mixtures have been used to test
the validity of viscosity relations developed for non-ideal solutions.
Preparation and properties of some triphenyllead carboxylates
Authors: Deacon GB , Felder PW
Published: September 2010

The triphenyllead
carboxylates, Ph3PbO2CR (R = C6F5,
4-MeOC6F4, 4-

EtOC6F4, 2,4-(NO2)2C6H3,
or C6Cl5) have been obtained by
reactions of triphenyllead acetate with the
appropriate carboxylic acids. The first four compounds are monomeric with
unidentate carboxylate coordination in chloroform, and all are probably
polymeric with bridging carboxylate groups in the solid state. The compounds, Ph3PbO2CR (R = C6F5,
4-RieOC6F4, or 4-EtOC6F4), undergo decarboxylation in
boiling pyridine to give the corresponding polyfluoroaryltriphenyllead
derivatives, but the other carboxylates do not decompose in a similar manner.
The phenylmercuric
carboxylates, PhHgO2CR (R = 4-MeOC6F4 or 4-EtOC6F4),
have also been prepared and
shown to decarboxylate to the corresponding 4-alkoxytetrafluorophenylphenylmercurials. Cleavage of the
compounds, Ph3PbR (R = C5F6
or 4-1MeOC6F4), with pentafluorobenzoic acid yields diphenyllead
bispentafluorobenzoate.
Rearrangements of ethylene oxide derivatives. V. The boron trifluoride catalysed rearrangement of some 1,1-disubstituted ethylene oxides
Authors: Blackett BN , Coxon JM , Hartshorn MP , Richards KE
Published: September 2010

The boron trifluoride
catalysed rearrangement of the unsymmetrical epoxide (3) to give aldehyde (5)
proceeds by selective (c. 1.9: 1) migration of the hydrogen atom (Hb) cis
to the methyl group.
Polysaccharides of tropical pasture herbage. I. Studies on the distribution of the major polysaccharide components of spear grass (Heteropogon contortus) during growth
Authors: Blake JD , Richards GN
Published: September 2010

The total carbohydrate content of spear grass stalk and leaf at several different stages of growth has been separated into fractions by a sequence of extraction procedures and each major polysaccharide fraction has been analysed for its monomer composition. As growth advanced the low molecular weight carbohydrates (sucrose, glucose, fructose) decreased, while hemicelluloses and cellulose increased in relative amount. Hemicelluloses, which are the major type of component in the plant, were predominantly of the B-type in the leaf, but both A- and B-types were present in the stem. The hemicellulose A-fractions contained proportionately less arabinose and uronic acid and more xylose than the corresponding B-fractions.
Solvent extraction studies of the system 64Cu/Htta/topo and the role of the metal complexes involved
Authors: Jacobs EB , Walker WR
Published: September 2010

Solvent extraction studies have been carried out on the system Cu/Htta/topo (Htta = thenoyltrifluoroacetone; topo = tri-n-octylphosphine oxide) with benzene as the organic phase. Using 64Cu as a tracer, equilibrium constants have been evaluated and compared with data obtained from the back-extraction of the labelled ternary complex 64Cu(tta)2(topo). The solubilities of binary and secondary complexes that are involved in synergistic extraction have also been measured.
The fluorescence of pyrene in frozen solutions
Authors: McDonald RJ , Selinger BK
Published: September 2010

Previous results and
theories concerning the emission of light from frozen solutions of pyrene in
hydrocarbon solvents are examined in the context of the present experiments. It
is suggested that the results are due to the formation of pyrene crystals, which
exhibit ?excimer? fluorescence.
Studies on intramolecular alkylation. I. The preparation of tricyclic intermediates for the synthesis of diterpene alkaloids
Authors: Beames DJ , Mander LN
Published: September 2010

The tricyclic dienones
(14), (16), and (16) have been prepared by the Ar1-6
cyclization of a diastereomeric mixture of 7-[(2?-bromo-1?- tetrahydropyranyloxy)-ethyl]-5,6,7,8-tetrahydro-2-naphthols
(11) and of 7-diazoacetyl-5,6,7,8-tetrahydro-2-naphthol (17). Intermediates
(11) and (17) were prepared by standard procedures from 1,2,3,4-tetrahydro- 7-hydroxy-2-naphthoic
acid.
The spectra of polywater
Authors: Gardiner RG , Mansfield WW , Willing RI
Published: September 2010

The properties of polywater
resemble those of mixtures of short-chain carboxylates and carbonates. Such
mixtures could be formed by handling capillaries during their preparation, and
they are present in optical tissues. ��� It is suggested that polywater consists of
impurities introduced from these or similar sources. Condensates containing
polywater are not formed when apparatus is steamed thoroughly.
Conformational transitions in block copolymers in solution from light scattering data
Authors: Girolamo M , Urwin JR
Published: September 2010

Data obtained from light
scattering studies on block copolymers of styrene and isoprene, in the solvent
cyclohexane, show a change in apparent radius of gyration as a function of
temperature at the same temperature, Tp, as was observed in studies
of [η] against T in this solvent. The phenomenon observed in these
independent experimental methods is believed to be due to a change in the
hydrodynamic volume of the polymer, brought about by an intramolecular
rearrangement of the molecule, from a phase-separated to a phase-mixed
conformation, as the temperature increases through Tp.
Denaturation of proteins. III. N.M.R. studies on lysozyme and α-lactalbumin
Authors: Bradbury JH , King NLR
Published: September 2010

The denaturation process is
considered with particular reference to the application of N.M.R. spectroscopy
for its study. All known examples of exchange between native and unfolded
states are shown to be cases of slow exchange on the N.M.R. time scale. Furthermore,
providing the denaturation is two-state, the fraction of unfolded molecules
α can be obtained from measurements of the heights of various N.M.R.
resonances, including those which are composites of several closely related
types of protons. The experimentally measured parameter F does not equal α
if intermediates are present or in the very unlikely event of the denaturation
process occurring rapidly on the n.m.r, time scale. Multiple-state
denaturations can be observed by the non-coincidence of curves of F (determined
from different resonances) against denaturant parameter or from the occurrence
of proton resonances which are only observed in the transition region. ��� Lysozyme is not denatured in 8M urea at pH
> 3.0. At pH 2.8 the NH resonances of arginine sharpen before those of many
other proton resonances in the molecule which sharpen simultaneously. It is
concluded that three clusters of arginine side-chains, which involve seven
arginine residues, unfold before the bulk of the molecule. Denaturation of
α-lactalbumin in urea at pH 2.5 and pH 6.0 in D2O occurs over a
broad range of concentrations and is clearly multiple state at pH 6.0. ��� The N.M.R. study shows the presence of an
exposed methionine residue in α-lactalbumin, no evidence of high field
perturbed methyl resonances, and a considerably reduced stability to
denaturation as compared with lysozyme. The dearth of aliphatic-aromatic
interactions in α-lactalbumin may account for its more open structure
compared with lysozyme as well as its reduced stability towards denaturation.
Annelated furans. VI. Diels-Alder addition to 3-Methoxy-2-vinylbenzofurans
Authors: Brewer JD , Davidson WJ , Elix JA , Leppik RA
Published: September 2010

The Diels-Alder addition of
3-methoxy-2-vinylbenzofurans to acetylenic
dienophiles has been shown to be accompanied by elimination of methanol, thus
affording a direct route to polyfunctional dibenzofurans. Ethylenic dienophiles
also reacted but the nature of the product varied with the dienophile: thus
tetra-cyanoethylene and 2- isopropenyl-3-methoxybenzofuran (17) gave the simple
1 : 1 adduct, 1,1,2,2-tetracyano-11-methoxy-4-methyl-1,2,3,11-tetrahydrodibenzofuran
(26), while addition of maleic anhydride to (17) was accompanied by elimination
of methanol to form the 1,2-dihydrodibenzofuran, 4-methyl-
1,2-dihydrodibenzofuran-1,2-dicarboxylic acid anhydride (27). ��� The addition of p-benzoquinone and
1,4-naphthaquinone to (17) gave the polycyclic quinones, 6-methyl-1,4-dioxo-1,4-
dihydrobenzo[b]naphtho[1,2-d]furan (28) and 7-methyl-5,13-dioxo-5,13-
dihydrobenzo[b]anthra[1,2-d]furan (29) respectively. ��� The methylation of enolic
3-hydroxybenzofurans has also been studied.
Thermodynamics of metal-ligand bond formation. II. Zinc, cadmium, and mercury(II) complexes of o,o-dialkyldithiophosphates
Authors: Dakternieks DR , Graddon DP
Published: September 2010

The reactions of 0,O-dialkyldithiophosphato complexes, {(R0)2PSz}zM
(M = Zn, Cd, Hg), to form dimers and 1 : 1 and 1 : 2 adducts with pyridine have
been studied calorimetrically in benzene solution a t 30�C. While variation of the
alkyl group has little effect, variation of the metal atom causes marked changes in
both free energies and enthalpies of reaction. Average values of thermodynamic
data obtained are as follows (AGOao3 and AH0300 in k J mol-l, AS0a03 in J K-l mol-l) :
Carbonyl halides of the Group VI transition metals. XXIV. 1,2-Bis(diphenylarsino)ethane complexes of the molybdenum(II) halocarbonyls
Authors: Anker MW , Colton R
Published: September 2010

Complexes of the general
formulae Mo(CO)3(dae)X2 and
[Mo(CO)2(dae)1.5X2]2
[X = Cl, Br, I; dae =
1,2-bis(diphenylarsino)ethane] have been prepared and characterized. The
chloro- and bromo-tricarbonyl species exist in two isomeric forms. All of the dae-bridged dimeric complexes can be cleaved by carbon
monoxide, to reform the corresponding tricarbonyl, and by excess dae to give soluble dicarbonyl compounds which are thought
to be of the type Mo(CO)2(dae)2X2.
Unfortunately, the equilibria

�������������� [Mo(CO)2(dae)1.5X2]2+dae
↔ 2Mo(CO)2(dae)2X2

are very labile, and all
attempts to isolate the bis(dae) complexes in a pure
form resulted in the precipitation of the sparingly soluble dimeric species. ��� Comparison of the complexes derived from
the halocarbonyls with dae and other ditertiary
phosphines and arsines shows that, as the halogen is varied, the changes in the
relative stabilities of the complexes obtained within each ligand series are
all explicable on the basis of a self-consistent steric argument, but comparison
of the complexes of dae and its diphosphine analogue,
dpe, suggests that electronic effects become
significant on changing from arsenic to phosphorus donor atoms.
Long-range couplings in the N.M.R. spectra of isoquinolines
Authors: Balkau F , Heffernan ML
Published: September 2010

The N.M.R. spectra of
several isoquinolines have been recorded and analysed. Extensive spin-decoupling
allowed the magnitudes and relative signs of the long- range coupling constants
to be determined, and these are presented. Several unusual features of the
chemical shifts and coupling constants are noted.
Mass spectrometric identification of cadmium(II) chlorobromide
Authors: Bloom H , Anthony RG
Published: September 2010

Mass spectrometric studies
above solid CdCl2 + CdBr2 mixtures in the temperature
range 720-770 K have revealed the existence of "mixed halide" gaseous
species of formula CdClBr. The heat of formation of CdClBr(g) from CdCl2(g) and CdBr2(g)
has been found to be 0.4 � 1 kcal/mol. It is reasoned that the driving force
for "mixed halide" formation is associated with a decrease in
molecular symmetry.
The self-association of Pyrrolid-2-one in acetonitrile and chloroform: An N.M.R. spectroscopic study
Authors: Blackwell LF , Buckley PD , Jolley KW , Watson ID
Published: September 2010

The self-association of
pyrrolid-2-one has been studied in CDCl3 and CD3CN at
several temperatures by the use of high resolution nuclear magnetic resonance
spectroscopy. The enthalpies of self-association of the lactam in the two
solvents have been measured and are in reasonable agreement with those for
similar systems determined by the use of other methods. The enthalpy of
salvation of pyrrolid-2-one in CHCl3 has also been measured. A
discussion on the validity of the approximations used in the calculations of
the thermodynamic parameters has been included.
The dependence of the rate of electrochemical charge transfer on the electric field at the metal-electrolyte interface
Authors: Matthews DB
Published: September 2010

Electric fields at the
metal-electrolyte interface are very high (of the order of 107 V/cm)
and one intuitively expects that these fields should have a profound influence
on the movement of charged species such as ions and electrons at the interface.
Qualitatively, such field effects manifest themselves as deviations from
linearity of Tafel plots or as a dependence of the
symmetry factor on electrode potential. It is shown that Gurney's potential
energy curve representation of charge transfer reactions yields
only small changes in β over a wide range of potential, with the anharmonic (Morse) curves showing smaller changes than the
harmonic (parabolic) curves. Superposition of the double layer electric field
on these potential energy curves increases the curvature of the Tafel plots, but the effect is still not very large, being
within the limits of uncertainty in determining the correct form of the
potential energy curves. The effect of electric field on electron transfer is
considered both from the viewpoint of change in electron transfer distance
arising from a dependence of coordinates of the activated state on potential
and from the viewpoint of a direct effect on the electron transfer barrier
(analogous to field electron emission). The field emission effects are found to
be even less than the effects of the field on the proton transfer potential
energy barrier.
Thio-derivatives of 1,3-diketones and their metal complexes ; O-ethyl thioacetothioacetate and its zinc(II), cadmium(II), and mercury(II) derivatives
Authors: Hendrickson AR , Martin RL
Published: September 2010

The synthesis of O-ethyl thioacetothioacetate
and its zinc(11), cadmium(11), and mercury(11) complexes are described,
together with the zinc(11) and cadmium(11) complexes of ethyl thioaoetoacetate. Infrared, visible, ultraviolet, nuclear
magnetic resonance, and mass spectra have been used to characterize the free
ligand and the new complexes. The free dithio-ligand
is shown to exist in a thioenol form with the thiol
function located at the aceto grouping. The
tetrahedral 1,3-dithio complex, bis(O-ethyl
thioaoetothioacetate)zinc(11) is discussed.
Some elimination reactions of hydroxy tosylates in the bornane series
Authors: Cole RFM , Coxon JM , Hartshorn MP
Published: September 2010

The reaction of cis-bornane-2,3-diol monotosylates
with potassium t-butoxide in t-butyl alcohol gives
exclusively the corresponding born-2-ene epoxide; trans-bornane-2,3-diol monotosylates give
a ketone in addition to the epoxide.
Steric course and kinetics of aquation of some haloaquotetraamminechromium(III) complexes
Authors: Fee WW , Jackson WG , Vowles PD
Published: September 2010

The aquation
stoioheiometry of cis.
and trans-Cr(NH3),(OH2)Br2+
and cis- and trans-Cr(NH3)4(OH2)I2+
ions when either spontaneous, Hg2+ promoted, or carried out via the hydroxo forms generated in basic solution has been
examined. The two latter treatments have
been conducted on cis-Cr(NH3)4(OH2)C12+
ion. Spectrophotometric methods show all lose halide with retention of
configuration. The rates of aquation in acid media of the Cr(NH3)4(OH2)Br2+
and Cr(NH3),(OH2)I2+ ions have been
investigated and comparisons are made with related tetraammine
and bis(ethylenediamine) oomplexes.

Evidence
has accumulated to show almost complete stereoretentivity
in the aquation reactions of chromium(111) amine
complexes.
Fungal metabolites. I. Chromone and naphthoquinone metabolites from a Cylindrocarpon species
Authors: Coombe RG , Lowe HIC , Watson TR
Published: September 2010

Eugenitin (5-hydroxy-7-methoxy-2,6-dimethylchromone) and
2-acetonyl-3,5-dihydroxy-7-methoxy-1,4-naphthoquinone have been isolated from Cylindrocarpon
sp. C.M.I. 127996.
Chemistry of the Podocarpaceae. XL. Conversion of methyl 12-Hydroxypodocarpa-8,11,13-trien-19-oate into Methyl 13-hydroxypodocarpa-8,11,13-trien-19-oate
Authors: Cambie RC , Mathai KP , Missen AW
Published: September 2010

Methods for the conversion
of methyl (+)-12-hydroxypodocarpa-8,11,13- trien-19-oate (7) into the
synthetically more useful compound methyl (+)-13-methoxypodocarpa-8,11,13-trien-19-oate
(8) have been investigated. In the most favourable
case, the transformation has been effected in c. 57% yield by a five-stage
sequence involving hydrogenolysis of the 13-amino-12-tosylate (31) with Raney
nickel.
Interactions Between Incentive Instruments: Contracts and Quality in Processing Tomatoes
Authors: Goodhue Rachael E. , Mohapatra Sandeep , Rausser Gordon C.
Published: September 2010

Contracting and other forms of vertical coordination are important parts of the supply chains for many agricultural products. Often the buyer cares about multiple product attributes affected by a grower's actions. Using data that are insulated from common methodological problems, we test whether or not price incentives for two processing tomato quality attributes exhibit complementarity in improving delivered quality. Price incentives for the two attributes are substitutes for the provision of one and complements for the other. This finding has consequences for the profit‐maximizing choice of incentive instruments for processors, and contributes to the literature regarding tests for complementarities.
Homocitrate synthase connects amino acid metabolism to chromatin functions through Esa1 and DNA damage
Authors: Scott Erin M. , Pillus Lorraine
Published: September 2010

The enzyme homocitrate synthase (HCS) catalyzes the first step in lysine biosynthesis, and early biochemical data placed it in the cytoplasm or mitochondria, where most amino acid synthesis occurs. It was therefore surprising when refined fractionation techniques and specific immunoreagents clearly demonstrated its localization to the nucleus. These observations raised the question of whether HCS had a function within the nucleus independent of lysine synthesis. We demonstrate that HCS encoded by LYS20 in yeast is linked to the key process of DNA damage repair through the essential MYST family histone acetyltransferase Esa1 and the H2A.Z histone variant. This discovery indicates that HCS has a role in addition to amino acid synthesis, and that it functions in nuclear activities involving chromatin regulation that are distinct from its previously established role in lysine biosynthesis. The chromatin-linked roles are dependent on nuclear localization of Lys20, but are independent of HCS catalytic activity. Thus, Lys20 appears to have evolved as a bifunctional protein that connects cellular metabolism with chromatin functions.
Large-Scale Extraction of Recombinant Proteins from Bacteria
Authors: Simpson Richard J.
Published: September 2010

INTRODUCTION

Bacteria are particularly convenient for producing recombinant proteins for purification purposes. Suitable extraction methods for bacterial cells include sonication, glass bead milling, grinding with alumina or sand, high-pressure shearing using the French pressure cell (French Press), and lysozyme treatment. These procedures are applicable for preparing extracts from a variety of Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae, and Gram-positive bacteria such as Bacillus subtilis. Disruption of bacterial cells by enzymatic means is commonly used because a relatively uniform treatment is obtained when cells are in suspension. This protocol describes the enzymatic disruption of E. coli.
The Cytosolic Tail Dipeptide Ile-Met of the Pea Receptor BP80 Is Required for Recycling from the Prevacuole and for Endocytosis
Authors: Saint-Jean Bruno , Seveno-Carpentier Emilie , Alcon Carine , Neuhaus Jean-Marc , Paris Nadine
Published: September 2010

Pea (Pisum sativum) BP80 is a vacuolar sorting receptor for soluble proteins and has a cytosolic domain essential for its intracellular trafficking between the trans-Golgi network and the prevacuole. Based on mammalian knowledge, we introduced point mutations in the cytosolic region of the receptor and produced chimeras of green fluorescent protein fused to the transmembrane domain of pea BP80 along with the modified cytosolic tails. By analyzing the subcellular location of these chimera, we found that mutating Glu-604, Asp-616, or Glu-620 had mild effects, whereas mutating the Tyr motif partially redistributed the chimera to the plasma membrane. Replacing both Ile-608 and Met-609 by Ala (IMAA) led to a massive redistribution of fluorescence to the vacuole, indicating that recycling is impaired. When the chimera uses the alternative route, the IMAA mutation led to a massive accumulation at the plasma membrane. Using Arabidopsis thaliana plants expressing a fluorescent reporter with the full-length sequence of At VSR4, we demonstrated that the receptor undergoes brefeldin A–sensitive endocytosis. We conclude that the receptors use two pathways, one leading directly to the lytic vacuole and the other going via the plasma membrane, and that the Ileu-608 Met-609 motif has a role in the retrieval step in both pathways.
ArabidopsisVILLIN5, an Actin Filament Bundling and Severing Protein, Is Necessary for Normal Pollen Tube Growth
Authors: Zhang Hua , Qu Xiaolu , Bao Chanchan , Khurana Parul , Wang Qiannan , Xie Yurong , Zheng Yiyan , Chen Naizhi , Blanchoin Laurent , Staiger Christopher J. , Huang Shanjin
Published: September 2010

A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the villin/gelsolin/fragmin superfamily of actin binding proteins and is composed of six gelsolin-homology domains at its core and a villin headpiece domain at its C terminus. Recently, several villin family members from plants have been shown to sever, cap, and bundle actin filaments in vitro. Here, we characterized a villin isovariant, Arabidopsis thaliana VILLIN5 (VLN5), that is highly and preferentially expressed in pollen. VLN5 loss-of-function retarded pollen tube growth and sensitized actin filaments in pollen grains and tubes to latrunculin B. In vitro biochemical analyses revealed that VLN5 is a typical member of the villin family and retains a full suite of activities, including barbed-end capping, filament bundling, and calcium-dependent severing. The severing activity was confirmed with time-lapse evanescent wave microscopy of individual actin filaments in vitro. We propose that VLN5 is a major regulator of actin filament stability and turnover that functions in concert with oscillatory calcium gradients in pollen and therefore plays an integral role in pollen germination and tube growth.
Methods in pharmacology: measurement of cardiac output
Authors: Geerts Bart F. , Aarts Leon P. , Jansen Jos R.
Published: September 2010

Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. The ‘holy grail’ for the measurement of cardiac output would be a method that is accurate, precise, operator independent, fast responding, non‐invasive, continuous, easy to use, cheap and safe. This method does not exist today. In this review on cardiac output methods used in pharmacology, the Fick principle, indicator dilution techniques, arterial pulse contour analysis, ultrasound and bio‐impedance are reviewed.
Serum transforming growth factor β1 during diabetes development in non-obese diabetic mice and humans
Authors: Olivieri A , De Angelis S , Dionisi S , D'Annunzio G , Locatelli M , Marinaro M , Bonato V , Amendola A , Songini M , Velluzzi F , Schirru C , Cotichini R , Stazi M A , Dotta F , Lorini R , Bottazzo G F , Boirivant M
Published: September 2010

Recent data show that regulatory cells with transforming growth factor (TGF)-β1-dependent activity are able to restore self-tolerance in overtly diabetic non-obese diabetic (NOD) mice. Thus, TGF-β1 seems to have a relevant role in protection from autoimmune diabetes. Our aim was to investigate the possible significance of serum TGF-β1 measurement in the natural history of diabetes in NOD mice, as well as in children positive for at least one islet-related antibody. Serum TGF-β1 (both total and active) was measured by enzyme-linked immunosorbent assay at monthly intervals in 26 NOD mice during the spontaneous development of diabetes and, on a yearly basis, in nine siblings of patients with type 1 diabetes (T1D) with a follow-up of 4 years. Diabetes appeared between the 12th week of age and the end of the study period (36 weeks) in 17 mice. TGF-β1 serum level variations occurred in the prediabetic period in both NOD mice and humans and diabetes diagnosis followed a continuing reduction of active TGF-β1 (aTGF-β1) serum levels. In mice, aTGF-β1 serum levels measured at 4 weeks of age correlated positively with severity of insulitis, and negatively with percentage of insulin-positive cells. Our findings suggest that in NOD mice serum TGF-β1 levels during the natural history of the diabetes reflect the course of islet inflammation. The measurement of aTGF-β1 in islet-related antibody-positive subjects may provide insights into the natural history of prediabetic phase of T1D.
Trace elements in nails as biomarkers in clinical research
Authors: He Ka
Published: September 2010

Eur J Clin Invest 2010; 41 (1): 98–102

Background  The importance of trace elements in relation to human health has been increasingly recognized. Accurate and adequate quantification of trace elements are crucial in clinical research.

Design  This review was to discuss the rationale of using nail trace elements as biomarkers in clinical studies.

Results  For most trace elements, dietary instruments cannot appropriately capture the intakes because of the minimal amounts and wide variations in the same foods grown in different area as well as the nondietary exposures. Therefore, biomarkers may be essential in studying trace elements. Although there are notable differences among trace elements in the availability of biomarkers, increasing evidence supports that nails, particularly toenail concentrations of most trace elements, are useful biomarkers of exposure in which a single sample is assumed to represent long‐term exposure.

Conclusions  Compared with other potential biomarkers of trace elements, nail measurement has certain advantages in clinical research.
The impact of smoking on incident type 2 diabetes in a cohort with hepatitis B but not hepatitis C infection
Authors: Wang C.‐S. , Chang T.‐T. , Yao W.‐J. , Wang S.‐T. , Chou P.
Published: September 2010

Smoking may be a risk factor for diabetes, and it has been suggested that viral hepatitis may predispose to diabetes. We studied diabetes and smoking histories in people with viral hepatitis. From 1997 to 2004, we studied the risk of incident diabetes in a community cohort with hyperendemic HBV and HCV infection in southern Taiwan. The cohort involved 3539 people (40–70 years old) without diabetes. Four hundred and twenty‐three individuals developed diabetes. Those who were ≥65 years old, frequently consumed alcohol, had a BMI ≥25, had <9 years of education, were anti‐HCV+ or smoked ≥1 pack per day were more likely to develop diabetes (P < 0.05). A cumulative hazard function test showed that the higher the smoking levels, the greater the cumulative incidence rate of diabetes in HBsAg+ participants only (P = 0.03 by log‐rank test). A multiple Cox proportional hazards model analysis in different hepatitis statuses showed smoking levels were strong predictors of diabetes with a dose–response relationship for type 2 diabetes in those with HBsAg+: hazard ratio (HR) = 3.8, (95% CI: 1.2, 12.3) for light smokers (<1 pack per day) and HR = 4.4 (95% CI: 1.5, 13.3) for heavy smokers (≥1 pack per day). Increasing BMI was a common predictor in all people. Smoking is a strong predictor for diabetes with a dose–response relationship in HBsAg+ individuals and a mild predictor for seronegative individuals but not significant in anti‐HCV+ individuals.