bluuebunny/crossref_metadata_2025 huggingface dataset:
The Perceived Structural Shape of Thin (wire-like) Objects is Different from That of Silhouettes
Authors: Bertamini Marco , Farrant Tracy
Published: December 2006

Observers are faster at judging the position of convex vertices compared to concave vertices. This is believed to be due to an explicit representation of position for visual parts. The best evidence comes from comparing the same contours perceived as either figures or holes, because this is a pure figure – ground reversal (Bertamini and Croucher, 2003 Cognition87 33 – 54; Bertamini and Mosca, 2004 Perception33 35 – 48). Specifically, an interaction is present between type of object (object or hole) and shape. One assumption is that the contour of a silhouette is perceived as the rim of a solid object. It follows that a different pattern should be found for thin (wire-like) objects compared to silhouettes. We confirm this difference in three experiments. We argue that this is due to the perceived parts when contours can be interpreted as self-occlusion rims.
Analyzing Biochemical Pathways Using Neural Networks and Genetic Algorithms
Authors: Gasteiger Johann , Reitz Martin , Han Yongquan , Sacher Oliver
Published: December 2006

The analysis of biochemical pathways has recently gained much interest as these are the processes that keep us alive. A deeper understanding of biochemical reactions must analyze them at atomic resolution. In order to achieve that we have developed a reaction database with the information on the well known Biochemical Pathways wall chart. Based on that, 3D models of the substrates and intermediates of biochemical reactions can be built. It is shown how this information can be used for searching for inhibitors of enzyme catalyzed reactions by superimposition of 3D structures with a genetic algorithm. Physicochemical properties of the bonds directly involved in the reaction event allow a classification of these enzyme catalyzed reactions by self-organizing neural networks. This classification is compared with the enzyme code (EC) classification.
An Approach Toward Emulating Molecular Interaction with a Graph
Authors: Suzuki Hideaki
Published: December 2006

Network artificial chemistry (NAC) uses a mathematical graph to emulate molecular interaction in a solvent. To emulate molecules' movement in a three-dimensional space, rewiring rules for NAC graphs’ edges must be designed to enable the edges to imitate the relations between molecules or atomic clusters. Our research formulated the ‘network energy’ representing this constraint and rewired the NAC graph to minimize the required energy. Experimental results for the NAC rewiring are compared with a hard-sphere random walk simulation.
Cellular Automata Simulations of Vapor–Liquid Equilibria
Authors: Seybold Paul G. , O'Malley Matthew J. , Kier Lemont B. , Cheng Chao-Kun
Published: December 2006

Phase transitions and phase equilibria are among the most fundamental phenomena in the physical and environmental sciences. In the present work an asynchronous stochastic cellular automata model for the equilibrium between a liquid and its vapor is presented. The model is visual, dynamic, and employs just two rules—an attraction probability and a gravitational preference. Application of the attraction rule alone yields a ‘mist’ within the vapor, whereas application of the gravitational rule by itself yields an isothermal atmospheric profile. Application of both rules together causes the vapor to evolve to a liquid phase with a vapor phase above it. Introduction of a third rule for short-range attraction/repulsion more clearly resolves the liquid/vapor interface.
Absolute Configurations of Naturally Occurring Quinones: Ventilagone and Dunnione
Authors: Cooke Raymond G. , Ghisalberti Emilio L. , Johnson Brian L. , Raston Colin L. , Skelton Brian W. , White Allan H.
Published: December 2006

Low-temperature determinations of the crystal structures of the naturally occurring quinones ventilagone (as its p-bromobenzyl ether) and dunnione (as its p-bromophenylhydrazone) permit the assignment of their absolute configurations as (1R,3S)-7,10-dihydroxy-1,3,8-trimethyl-3,4,6,9-tetrahydro-1H-naphtho[2,3-c]-pyrane-6,9-dione 1 and (2R)-2,3-dihydro-2,3,3-trimethylnaphtho[1,2-b]furan-4,5-dione 2.
Simulation and Modelling of Chemical and Biological Complex Systems
Authors: Polley Mitchell J. , Burden Frank R. , Winkler David A.
Published: December 2006

Most sciences, and notably chemistry and biology, are becoming more interdisciplinary with overlaps between disciplines providing fertile new fields of research. As scientists attempt to model more complicated matter such as protein complexes, regulatory networks, cells, smart materials, biomaterials, and the like, it is clear that the complexity of these systems is difficult to describe using traditional reductionist tools. We describe how the tools and concepts of complex systems science may be applied to the simulation and modelling of complex chemical and biological systems.
Errors in Determining the Rate Constant of a First-order Gaseous Reaction by the Flow Method
Authors: Mulcahy MFR , Pethard MR
Published: December 2006

The rate constant of a gaseous reaction
calculated from data obtained by the conventional flow method is subject to
errors arising from departures from piston flow and thermal equilibrium in the
reaction tube. An approximate theoretical analysis of the errors is given for
the first-order pyrolysis or isomerization of an organic vapour. In the case of
a reaction occurring near 1000�K in a tube 2 cm in diameter, it is shown that
for the measured value of the rate constant to be accurate within about 10% the
experimental conditions should be such that z > tc/p
> 0.5, where p cmHg is the total pressure and tc
sec the average contact time. The upper limit (z) of tc/p
increases from 3 under conditions of 50% conversion to 10 at 25% and ∞ at
0%.

The analysis is applied to measurements of
the rate of pyrolysis of toluene. Lack of thermal equilibrium could be at least
partly responsible for the observed effect of contact time on the rate constant
but does not account for the effect of pressure.

The error incurred by assuming piston flow
in an isothermal reactor when in fact viscous flow is occurring is discussed in
the Appendix.
Paramagnetic Products of the Oxidation of Cyanocobaltate(II)
Authors: Bayston JH , Looney FD , Winfield ME
Published: December 2006

By means of a low-temperature ESR
technique, several paramagnetic complexes have been detected during the
reaction of aqueous [CoII(CN)5]3- with O2.
Of these only [(CN)5CoIII-O-O-CoIV(CN)5]5-,
the final oxidation product, is stable in solution. It has a 15-line spectrum
resembling that of [(NH3)5CoIII-O-O-CoIV(NH3)5]5+
but more sharply defined and independent of pH.

Under very alkaline conditions the first
oxidation product detectable by ESR has an 8-line signal, indicating a
mononuclear complex, possibly [(CN)5CoIII-O-O]3-.
It is an intermediate in the oxidation of [(CN)5CoIII-O-O-CoIII(CN)5]6-
to [(CN)5CoIII-O-O-CoIV(CN)5]5-
and may reach a high concentration in the presence of 0.5M KOH. Although it may
also prove to be the expected mononuclear inter- mediate in the oxidation of
[CoII(CN)5]3- to [(CN)5CoIII-O-O-CoIII(CN)5]6-,
no 8-line signal is detected until the cyanocobaltate(II) has been consumed.

Present in small amount is a mononuclear
complex with 16 lines, apparently a by-product. Larger amounts can be formed by
reducing [(CN)5CoIII-O-O-CoIII(CN)5]6-
with NaBH4 in strong alkali at -20�C.
Conductances of Some Group V Quaternary 'onium Iodomercurate(II) Complexes
Authors: Deacon GB , West BO
Published: December 2006

Conductances of dilute solutions of
iodomercurate(II) complexes of the stoicheiometries, M2HgI4,
MHgI3, and MHg2I5 (where M is a Group V
quaternary 'onium cation), in acetone have been measured. The effect of
dissociation of the complexes on the conductance is discussed.
Solvation of Ions. V. Rates of SN2 Reactions in Mixtures of Protic and Dipolar Aprotic Solvents
Authors: Parker AJ
Published: December 2006

The rates of reaction of methyl iodide
with chloride ion in some protic-dipolar aprotic solvent mixtures have been
measured. The rate-retarding effect of protic solvents at M concentration in
dimethylacetamide is in the order p-NO2C6H4OH
> C6H5OH > C6H5SH > C6H5CO2H
≈ CH3OH > C6H5NH2 >H2O
≈ D2O. Protic solvents slow the reaction by a general rather
than a specific hydrogen bonding interaction with the anion. Both the dipolar
aprotic solvent and the protic solvent, as well as the anion, accept hydrogen
bonds, and this influences the interaction between protic solvent and anion.
The Formation of Aromatic Hydrocarbons at High Temperatures. XVIII. The Pyrolysis of n-Decane
Authors: Badger GM , Novotny J
Published: December 2006

n-Decane has been pyrolysed at 700�C.
Fifty-two compounds have been identified in the resulting tar. Mechanisms of
formation are discussed.
The Formation of Aromatic Hydrocarbons at High Temperatures. XIX. The Pyrolysis of [δ-14C]Butylbenzene
Authors: Badger GM , Novotny J
Published: December 2006

The pyrolysis of [δ-14C]butylbenzene
at 700�C has given a tar from which 18 compounds have been isolated in
sufficient quantity and purity for radiochemical analysis. Five of these have
been degraded to show the location of labelled carbon atoms. The results are
discussed with reference to the mechanisms of the formation of the various
compounds from butylbenzene.
Perfluoroalkylbismuth Compounds. I. Mixed Alkylperfluoroalkyl Derivatives
Authors: Bell TN , Pullman BJ , West BO
Published: December 2006

Perfluoroalkyl iodides react directly with
trialkylbismuth compounds at 100�C to form dialkylperfluoroalkyl- and
alkylbisperfluoroalkylbismuthines. These previously unknown compounds decompose
below their boiling points. They are readily oxidized and may be hydrolysed by
aqueous alkali, liberating the appropriate fluorocarbon. Halogens rapidly split
off both alkyl and perfluoroalkyl groups. Whereas interconversion of the mixed
alkylperfluoroalkyl compounds readily occurs, attempts to form the fully perfluoroalkylated
bismuth compounds have been unsuccessful. Vapour pressure-temperature and
infrared spectral data are presented and discussed.
Synthesis and Rearrangement Reactions of 4α-Bromo-5α-cholestane-3α,5-diol 3-Acetate
Authors: Collins DJ
Published: December 2006

The structure of the
bromohydrin 4α-bromo-5β-cholestane-3β,5-diol 3-acetate (V),
obtained by the addition of hypobromous acid to cholest-4-en-3β-ol3-aoetate,
has been proved conclusively by an unequivocal synthesis from cholest-3-ene-5β-ol.

An equilibrium mixture (approx. 1 : 2) of
(V) and the isomeric bromohydrin 5-bromo-5α-cholestane-3β,4β-diol3-acetate
(IV; R = Ac) [prepared1 by the addition of HBr to 4β,5-epoxy-5β-cholestan-3β-ol
3-acetate (I; R = Ac)] resulted when either pure isomer was refluxed with a
trace of mineral acid in an inert solvent.

The 4β-hydroxy-5α-bromo
derivative (IV; R = Ac) can be acetylated or oxidized without rearrangement.
Interestingly, under mild conditions of acetylation or oxidation, the isomeric
bromohydrin (V) (having a tertiary 5β-hydroxyl) reacted with rearrangement
to give 5-bromo-5α-cholestane-3β,4β-diol 3,4-diacetate (II; R1
= R2 = Ac) or 5-bromo-5α-cholestan-4β-ol-3-one 4-acetate
(VI), respectively.

The acetylation of (V) to (II; R1
= R2 = Ac) does not proceed via equilibration of (V) with (IV; R =
Ac) and acetylation of the latter. Rather, it has been shown that through
participation of the 5β-hydroxyl, migration of the 3-acetate to the
4-position occurs with concomitant shift of the 4α-bromine to the 5α-position,
displacement of the 5β-hydroxyl, and acetylation at C3. Evidence for this
mechanism follows from the fact that treatment of (V) with benzoyl chloride in
pyridine afforded a benzoate different from that (II; R1 = Ac, R2
= Bz) obtainable from (IV; R = Ac), and identical with the 3-benzoate 4-acetate
(II ; R1 = Bz, R2 = Ac) which was synthesized from 4β,5-epoxy-5β-cholestan-3β-ol
3-benzoate (I; R = Bz) via 5-bromo-5a-cholestane-3β,4β-diol
3-benzoate (IV; R = Bz). The proposed mechanism is supported by other evidence.

It is suggested that the oxidative
rearrangement of (V) to (VI) proceeds by a mechanism similar to that which
operates in the acylation-rearrangement reaction, differing only in oxidation
rather than acylation at C3.
Colouring Matters of Australian Plants. XI. Quinones from Ventilago viminalis
Authors: Cooke RG , Johnson BL
Published: December 2006

The root bark of Ventilago viminalis Hook.
contains three new colouring matters now named ventimalin, viminalin, and
ventilagone. The first of these has been identified as
1,3,4,5,6-pentahydroxy-2-methylanthraquinone and the structure has been confirmed
by synthesis. Viminalin is shown to be the 4,5-dimethyl ether of ventimalin.
Ventilagone is apparently a naphthoquinone of the hydroxy- juglone type. Two
known anthraquinones, chrysophanol and islandicin, have also been isolated and
there is evidence for the presence of helminthosporin.
The Decomposition of Sodium Nitrite Solutions in Aqueous Sulphuric and Perchloric Acids
Authors: Bayliss NS , Watts DW
Published: December 2006

The kinetics of the decomposition of
aqueous solutions of sulphuric and perchloric acids containing sodium nitrite
have been investigated at a number of temperatures. The technique involved
flushing the decomposing solutions with dry nitrogen to remove the gaseous
products.

A first-order dependence of decomposition
rate on "analytical nitrite" was found, the rate constants being
dependent on the solvent acid composition.
The disproportionation of zirconium trichloride
Authors: Turnbull AG , Watts JA
Published: December 2006

Equilibrium pressures of the reaction 2ZrCl3(c) + ZrCl2(c)
+ ZrCl4(g) measured by a cooling curve
modification of the dew-point technique are fitted over the range 613-723�K, by
the relation

������ Log10pmm
= -6246/T ? 11.632 � 0.05 (S.D.).

Derived thermochemical
data are ΔH298 = 30.1
� 0.5 kcal and ΔS298
= 39.1 � 1 e.u., consistent with estimated ΔHf298ZrCl2
= - 136 kcal/mole and ΔHf298ZrCl2 = -136 kcal/mole, S298ZrCl3
= 36.4 e.u. and S298ZrCl2 =
28.3 e.u.
Reaction of the Pentacyanocobaltate(II) Ion with Molecular Oxygen
Authors: Bayston JH , Beale RN , King NK , Winfield ME
Published: December 2006

By spectrophotometric scanning of reacting
solutions, we have studied the processes which can occur when Oz is admitted to
aqueous solutions containing the Ion [CoII(CN)5]3-
in the concentration range 0.0002-0.4M, at 0�. A scheme is given to explain the
formation of and inter-relations between [(CN)5CoIII-O-O-CoIII(CN)5]6-;
[(CN)5CoIII-O-O-CoIV(CN)5]5-;
[(CN)5CoIIIOH2]2-
; [CoIII(CN)6]3-,
and a complex believed to be [(CN)5CoIII-O-OH]3-,
which absorbs at 272 mp Preparative methods are described for obtaining several
of the oxidation products in the crystaline state.

Hydrolysis of [(CN)5CoIII-O-O-CoIII(CN)5]6-
to [(CN)5CoIIIOH2]2-
takes place via the 272 mμ complex, which is
fairly stable in alkaline solution and is resistant to oxidation. The same 272 mμ complex can be formed more directly by oxygenation
of the hydrido complex [(CN)5CoIIIH]3-,
which is present in aged or hydrogenated solutions of pentacyanocobaltate(II).

All of the pentacyano oxidation products
can be reduced by sodium borohydride to [(CN)5CoIIIH]3-,
which is further reduced by excess borohydride to an insoluble green compound
and finally to metallic cobalt.

We have briefly examined the reactions of
ammonia and CN- with [(CN)5CoIIIOH2]2-,
and the reaction of [(CN)5CoIII-O-O-CoIV(CN)5]5-
with reducing agents, including [CoII(CN)5]3-.
The Oxidation of Ammonia Solutions by Silver(II) Oxide
Authors: Pickering WF
Published: December 2006

The oxidation by silver(II) oxide of
ammonia solutions varying in concentration from 0.09 to 0.97N has been studied
in the temperature range 20-50�. The products of the oxidation were found to be
nitrogen, ammonium nitrite, and ammonium nitrate. The amount of each product
formed was found to be dependent on the concentration of ammonia present and
the weight of silver oxide added, but independent of temperature. Rate
equations for each product have been obtained in the form dA/dt
= k(AgO)x.(NH4OH)y, where x is
of the order of 1.6 and y has values of the order of 0.30 and zero for the
formation of nitrogen and nitrate, respectively. For nitrite formation k equals
zero. The constant k incorporates two constants, one of which is common to the
three equations and is related to the formation of a transition complex on the
surface of the solid. It is suggested that this initial step is a chemisorption
process with an activation energy of about 18 kcal. A mechanism for the
reaction and the role of silver oxide in oxidations of ammonia catalysed by
silver salts are discussed.
The Nature of the Chelate Structures Formed by Copper(II) and Ovalbumin in the Biuret Reaction
Authors: Jennings AC
Published: December 2006

A spectrophotometric study was made of the
interaction, in alkaline solution, of copper(II) with ovalbumin and several
ligands of low molecular weight at several different atomic ratios of
nitrogen/copper. The results indicate that the absorbance and chemical
reactivity of the ovalbumin-copper(II) complex cannot be attributed to the
presence of one particular chelate structure. It is suggested that the
ovalbumin-copper(II) complex is a heterogeneous mixture of chelate structures
in which the copper(II) is bonded to oxygen (in the enolate form) and nitrogen
atoms in the several different combinations possible within the same
polypeptide chain. It is also suggested that the actual arrangement of bonds in
any one chelate structure is probably determined by both the nature of the
amino acid residues and the configuration of the ovalbumin molecule in the
immediate vicinity.
The Analysis of the Proton Magnetic Resonance Spectra of Heteroaromatic Systems. I. Indazole
Authors: Black PJ , Heffernan ML
Published: December 2006

The proton magnetic resonance spectrum of
indazole in acetone has been investigated at 100 Mc/s. The spectrum is of the
weakly coupled five-spin type. Transitions have been assigned on the basis of
first-order theory and the experimental energy levels obtained. The analysis
has been carried out with the aid of a digital computer using an iterative
procedure.

The presence of a long-range cross-ring
coupling constant of magnitude approximately 1 c/s is reported.
Electronic Conduction in Polymers. I. The Chemical Structure of Polypyrrole
Authors: McNeill R , Siudak R , Wardlaw JH , Weiss DE
Published: December 2006

The pyrolysis of tetraiodopyrrole in an
inert atmosphere at temperatures from 120-700� yields black, infusible,
amorphous polymers insoluble in solvents. Depending on the pyrolysis
temperature, iodine may be present in the polymers as iodine of substitution
and as chemisorbed molecular iodine, which is very tenaciously held. As a first
approximation, the structure may be regarded as a three-dimensional network of
pyrrole rings cross-linked in a nonplanar fashion by direct carbon to carbon
linkages. The secondary nitrogen atoms form a hydroquine type system which may
be oxidized by iodine or molecular oxygen under alkaline conditions. The extent
of oxidation depends on the hydroxyl ion concentration. The nonplanarity of the
oxidized quinonoid system renders it unstable but stability is enhanced, as in
the triphenylmethane dyestuffs, by the formation of a carbinol.

Despite their nonplanarity polypyrroles
are relatively good conductors of electricity. The resistivity ranges from
1-200 ohm cm depending on the temperature of pyrolysis.
The Proton Magnetic Resonance Spectrum of Rimuene
Authors: Carman RM
Published: December 2006

Astructure such as (II) is consistent with proton magnetic
resonance spectrum of rimuene.
Molecular susceptibility. The determination of molar Cotton-Mouton constants of solutes at infinite dilution
Authors: Le FFvre RJW , Williams PH , Eckert JM
Published: December 2006

The construction and testing of apparatus
for the measurement of magnetic birefringences of liquids are described. An
equation is developed whereby specific and molar Cotton-Mouton constants of
solutes may be obtained at infinite dilution from the magnetic double
refractions, densities, and refractive indices of solutions of known
concentrations. The results, when considered in conjunction with mean
susceptibilities from the literature and principal polarizabilities available
via the Kerr effect, can lead to specifications of molecular susceptibility
ellipsoids for the dissolved species. Nine solutes are now examined. For three
of these the principal susceptibilities have been previously recorded by the
Krishnan-Lonsdale techniques applied to crystals. The satisfactory agreement
between past and present values is held to justify the investigation as solutes
of liquids and other substances which, for various reasons, cannot be studied
by the "crystal" method.
Ion-molecule reactions in ketones
Authors: de Souza BC , Green JH
Published: December 2006

Reactions with gaseous ketones in the ion
source of a mass spectrometer at elevated pressures have been studied. Reaction
cross sections and approximate rate constants are reported for reactions
leading to ions of mass M + 1, where M is the mass of the parent ion. Proton
transfer rather than hydrogen abstraction seems to be the principal mode of
reaction in the formation of these secondary ions.
Some physical properties of aqueous solutions of tetramethylammonium bromide and tetramethylammonium iodide
Authors: Levien BJ
Published: December 2006

The activity coefficients up to
saturation, some conductances and densities, and the solubility in water have
been measured for tetramethylammonium bromide and tetramethylammonium iodide.
Ion association exists and the ion-pair constants have been calculated by three
methods. The standard entropy of the aqueous (CH3)4N+
ion has been calculated.
Molten salt mixtures. IX. The thermal conductivities of molten nitrate systems
Authors: Bloom H , Doroszkowski A , Tricklebank SB
Published: December 2006

The thermal conductivity of the molten
salts NaNO3, KNO3, AgNO3, and NaNO2
was measured by an equilibrium method over a range of temperature. Similar
measurements were carried out for the NaNO3
+ KNO3, AgNO3 + NaNO3, and AgNO3
+ KNO3 systems. The free volume of molten salts has been
calculated from thermal conductivity and is compared with results from sound
velocity determinations.
Free radicals in the reaction between t-butyl hydroperoxide and titanous ion: Some observations by electron spin resonance spectrometry
Authors: Mulcahy MFR , Steven JR , Ward JC
Published: December 2006

The reaction between t-butyl hydroperoxide
and titanous ion in aqueous solution produces free methyl radicals detectable
by electron spin resonance spectrometry (Dixon and Norman). However, the
presence of titanous ion in concentrations greater than 0.01M broadens the
spectrum of the methyl radical, causing it effectively to disappear at titanous
concentrations greater than 0.1M. At hydroperoxide concentrations above 0.25M
t-butyl peroxy radicals (identified by a strong single-line spectrum with
g-value 2.0136) are produced by the reaction

���������� R. + (CH3)3COOH
→ RH + (CH3)3COO.

Their concentration reaches
a maximum about 1 sec after the concentration of the methyl radicals has fallen
to an undetectable value and their half-life (≈ 5 sec) is about ten times
that of the methyl radicals.
Nucleophilic replacement of methoxyl in the reaction of a sterically hindered o-benzoquinone with o-phenylenediamine
Authors: Hewgill FR , Hewitt DG , Langley PB
Published: December 2006

With o-phenylenediamine,
3-t-butyl-5-methoxy-l,2-benzoquinone gives the quinone imine (VII), but only a
trace of the expected phenazine (II). Dilute acid converts (VII) to the
anilinophenazine (III). Chemical and spectroscopic evidence for the structures
of these compounds is presented.
Azaindoles. III. The synthesis of Pyrazolo[3,4-b]pyridines and Pyrazolo-[3,4-d]pyrimidines
Authors: Badger GM , Rao RP
Published: December 2006

Preparations of derivatives of
pyrazolo[3,4-b]pyridine and pyrazolo[3,4-d]-pyrimidine are reported.
Composition of the unsaponifiable matter of vernix caseosa
Authors: Downing DT
Published: December 2006

Detailed examination of the unsaponifiable
material from the skin wax of newly born babies has shown that the saturated
aliphatic alcohols contain a high proportion of branched-chain compounds, and
the aliphatic α,β-dials consist almost entirely of branched-chain
compounds. The sterol fraction consists of cholesterol, and a minor amount of
an unidentified sterol. The hydrocarbon fraction consists entirely of squalene.
Crystal structures of o-phenylenediarsine oxychloride (a redetermination) and o-phenylenediarsine oxybromide
Authors: Dewan JC , Henrick K , White AH , Wild SB
Published: December 2006

The crystal structures of
the title compounds have been established by X-ray diffraction at 295 K, being
refined by full-matrix least-squares to residuals of 0.054 (0.051) respectively
2715 (469) reflections with I > σ(I)]. Crystals are monoclinic, space group
C2/c, the compounds being isomorphous. Oxychloride: a = 14.534(4), b =
8.337(2), c = 7.653(1)Ǻ, β = 106.48(1)�. Oxybromide: a = 14.884(4), b
= 8.360(2), c = 7.726(1)Ǻ, β = 105.30(1)�, Z = 4. With the
exception-of the arsenic- halogen distance, the geometries of the two molecules
are identical within the limits of error: for the oxychloride As-O-As,
121.8(3); Cl- As-O,98.03(6); Cl-As-C,
97.2(2); O-As-C, 92. 9(2)� ; As-O, 1.787(3); As-C, 1.941(5) Ǻ. As-Cl is 2.222(2) and As-Br 2.381(2) Ǻ.
Metal complexes of 1,10-phenanthroline derivatives. IX. 5T2 ↔ 1A1 spin transitions in iron(II) complexes of 2-(1,10-phenanthrolin-2-yl)thiazole derivatives
Authors: Goodwin HA , Mather DW , Smith FE
Published: December 2006

The preparation of the tridentate
chelating agents 2-(1,10- phenanthrolin-2-yl)thiazole,
2-(1,10-phenanthrolin-2-yl)-4-(2- pyridyl)thiazole
2-(1,10-phenanthrolin-2-yl)thiazolidine and 2-(1,10- phenanthrolin-2-yl)benzothiazole
is described. Data from the spectra of the bis-ligand nickel complexes indicate
that the ligands all have field strengths in the iron(II) crossover region. The
temperature dependence of the magnetism of the bis-ligand iron(II) complexes
reveals that, except for the complexes of the pyridylthiazole, a smooth,
temperature-induced 5T2 ↔ 1A1
transition occurs in these compounds. For no complex is the transition complete
within the experimental temperature range (83-363 K). The complex of the
pyridylthiazole is high-spin throughout the range, the uncoordinated pyridyl
group hindering the close approach of ligand and metal atom necessary for
spin-pairing. The ability of the other ligands to induce a spin transition is
primarily a consequence of distortions in the environment about the metal atom
arising from coordination of the five- membered thiazole or related ring.
Physicochemical study on some synthesized oxazolidine derivatives : differentiation of diastereomers
Authors: Soliman SA , Abdine H , El-Nenaey S
Published: December 2006

The synthesis of 15
diastereomeric oxazolidine derivatives of the type 2-(substituted phenyl)-3,4-dimethyl-5-phenyloxazolidine
is reported. The specific as well as the molecular rotations of 31
diastereomeric oxazolidine derivatives of the same type of structure were
determined. The cis com- pounds have higher specific and molecular rotation
than the corresponding trans isomers. Substitution in the ortho or para
position increased specific and molecular rotation while substitution in the
meta position had an opposite effect. ��� The infrared spectra of 26 oxazolidine
derivatives, having either a cis or a trans type of configuration, have been
recorded in the range 2000-700 cm-1.
Some constituents of Austrobaileya scandens (Austrobaileyaceae) : structures of seven new lignans
Authors: Murphy ST , Ritchie E , Taylor WC
Published: December 2006

The aerial parts of Austrobaileya scandens C. T.
White (Austrobaileyaceae) yielded the known
substances β-sitosterol, its D- glucoside, the
sesquiterpene, spathulenol, and the lignan, deoxypicropodophyllin.
In addition, seven new lignans, austrobailignans-1 to -7, were isolated and
their structures, including absolute stereochemistry, elucidated. Two are
aryltetralin lactones, two are aryltetralins, two are bis-arylpropanes, and the
last is a tetrahydrofuran derivative. A triterpene acid mixture, to be investigated
further, was also obtained.
Constituents of the Fruit of Pseudopanax arboreum (Araliaceae)
Authors: Bowden BF , Cambie RC , Parnell JC
Published: December 2006

Saponification and
methylation of the acidic fraction of an extract of the fruit of the New
Zealand tree Pseudopanax arboreum has led to the isolation of a series of
ring-A substituted and ring-A seco triterpenoids possessing oleanane or ursane
skeletons. These include methyl 3-oxo-24-norurs-12-en-28-oate (1), dimethyl
4-oxo-3,24-dinor- 2,3-secours-12-ene-2,28-dioate (7), methyl
2α,3α,23-trihydroxyolean-12- en-28-oate (10), the ε-lactone of
23-hydroxy-4,17-dimethoxycarbonyl- 2,3-secours-12-en-2-oic acid (15), trimethyl
24-nor-2,3-secours-12-ene- 2,3,28-trioate (20), methyl
2-hydroxy-3-oxo-24-noroleana-1,4,12-trien- 28-oate (26), and methyl
2-hydroxy-3-oxo-24-norursa-1,4,12-trien-28- oate (27) whose parent acids have
not hitherto been obtained as natural products. Other compounds are methyl
2α,3α-dihydroxyolean-12-en-28-oate (9), methyl
2α,3α-dihydroxyurs-12-en-28-oate (23), methyl asiatate (24), methyl
arjunolate (13), the methoxy artefact (12), and the aryl- substituted methyl
cinnamates (28), (29), (30) and (31). Neutral constituents include the esters
(1), (9) and (10), stigmasterol and the sesquiterpene spathulenol (32).
Pyrazolidine-3,5-diones with heterocyclic substituents. II. Acylation of 5-Hydrazino-3-phenyl-1H-1,2,4-triazoles
Authors: Woodruff M , Polya JB
Published: December 2006

Basic condensation of
5-hydrazino-1-methyl-3-phenyl-1H-1,2,4-triazole with diethyl malonates gives
β-hydrazides of malonic acids, their decarboxylated products and
dihydrazides as the main products in low yields; diethyl monophenylmalonate and
diethylmalonate also afford the expected pyrazolidinediones in poor yield. The
corresponding β-benzoyl derivative resists pyrazolidinedione formation. N1-Benzoyl
derivatives of hydrazinotriazoles transacylated to the more basic hydrazine nitrogen.
The 4-phenylamino derivative of 6,6-diethyl-2-phenyl-s- triazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione
rearranges to the corresponding pyrazolidinedione but the analogous 4- benzoyl-amino
compound is demalonylated under the same conditions. Catalytic hydrogenation of
the 4-(2?-propylideneimino) analogue fails and attempted reduction by sodium
borohydride cleaves the pyrimidine ring.
Temperature dependence of ΔEQ for iron(IV) compounds in strong crystal field
Authors: Golding RM , Jessop KJ
Published: December 2006

An expression has been
derived for the temperature dependence of ΔEQ for d4
iron(IV) species in a strong crystal field. This expression has been used to
interpret Mossbauer data for some diarsine and dithiocarbamato iron(IV)
chelates.
Thermodynamic study of the deuterium isotope effect, the molar excess enthalpies of C6D6 + c-C6H12 and of C6H6 + c-C6H12
Authors: Mattingley BI , Fenby DV
Published: December 2006

Molar excess enthalpies of
C6D6 + c-C6H12 and of C6H6
+ c-C6H12 have been measured at 298.15 K; the equimolar
values are 818.7 and 797.0 J mol-1 respectively.
Syntheses of 4- and 5-Chloro-cis-1,3-dimethylindanes
Authors: Ashraf MC , Jackson WR , Rash D
Published: December 2006

Reaction of chlorobenzene
with crotonic acid under Friedel-Crafts conditions gives an unexpectedly high
proportion of 4-chloro-3- methylindan-1-one together with the expected
6-chloro-3-methylindan-1- one. Hydrogenolysis of the tertiary alcohols which
result from addition of methylmagnesium iodide to these compounds gives
predominantly cis-4- and -5-chloro-1,3-dimethylindanes with only small amounts
of the trans- isomers.
Chemical Examination of Local Plants. XIII. Elucidation of the Structure of a New Glycoside From the Leaves of Egyptian Hibiscus sabdariffa
Authors: Osman A , Younes M , Mokhtar A
Published: December 2006

The ether as well as the
methanol extracts of the defatted leaves of Hibiscus sabdariffa
yielded a new glycoside, the structure of which has been determined, by mass
and N.M.R. spectra and by synthesis, as β- sitosteryl β-D-galactoside.
Chemistry of the Podocarpaceae. LI. Ozonolysis products of Podocarpa-8,11,13-trien-12-ol
Authors: Cambie RC , Hayward RC
Published: December 2006

Podocarpa-8,11,13-trien-12-ol
(2) has been converted by ozonolysis and subsequent transformations into the
lactone (13), a tobacco flavouring agent, and into the bicyclic acetate (11) ,
a compound with a woody odour.
Base decomposition of heptamolybdate
Authors: Druskovich DM , Kepert DL
Published: December 2006

The reaction of
heptamolybdate, Mo7O246-, with excess hydroxide
ion proceeds through base-independent, and base-dependent, pathways. The
reaction is strongly dependent upon the salt chosen to maintain constant ionic
strength. The values of the base-independent rate constant increase in the
order K+(2.5 s-1 at 2.0 mol l-1 KCl and 25.0�C) < Na+ (9 s-1) <
Li+ (20 s-1) and those of the base-dependent rate
constant in the order K+ (8200 1. mol-1 s-1)
< Na+ (10300 1. mol-1 s-1) < Li+
(19600 1. mol-1 s-1). Extensive measurements in mixed
cation media show that the effect of ion pairing decreases in the order K+
> Na+ > Li+. The kinetic behaviour and activation
parameters are contrasted with those for the base decomposition of
decavanadate, V10O286-, and different mechanisms
are proposed.
Reaction of picryl chloride with sodium ethoxide: Formation of a C 3 σ-complex
Authors: Gan LH
Published: December 2006

Kinetic and spectroscopic
evidence is presented for the formation of a C3 σ-complex from picryl
chloride and sodium ethoxide in ethanol. Molar extinction coefficients of the
complex were determined by the Benesi- Hildebrand
method. Thermodynamic parameters were evaluated.
The complete ionization scheme for citric acid
Authors: Pearce KN , Creamer LK
Published: December 2006

The microacidity constants
for citric acid have been redetermined from pH titrations of citric acid and
selected methyl esters in aqueous solution at 25�C and at two ionic strengths.
The results obtained differ from those previously published. Calculated acidity
constants, derived from a careful consideration of the empirical substituent
effect, are also given and are in reasonable agreement with the experimental
acidity constants.
The synthesis of notatic acid and 4-O-Methylhypoprotocetraric acid
Authors: Cresp TM , Djura P , Sargent MV , Elix JA , Engkaninan U , Murphy DPH
Published: December 2006

The total synthesis of the
depsidones, notatic acid (1?-carboxy-2?-
hydroxy-4-methoxy-3,6,6?-trimethyl-depsidone) and 4-O- methylhypoprotocetraric
acid (1?-carboxy-2?-hydroxy-4-methoxy- 3,3?,6,6?-tetramethyldepsidone) is
reported.
Benzo[c]cinnoline derivatives. VII. Reactions of Benzo[c]cinnoline and Chlorobenzo[c]cinnolines with lithium dimethylamide.
Authors: Lewis GE , Prager RH , Ross RHM
Published: December 2006

The reactions of the four
isomeric chlorobenzo[c]cinnolines and unsubstituted benzo[c]cinnoline with
lithium dimethylamide in dimethylamine lead to the formation of complex product
mixtures. Di- methylaminations occur as primary
reactions at the 4- and 7-positions of the benzo[c]cinnoline nucleus; these
involve displacement of hydrogen even when a chloro substituent is attached to
another position in the same ring. Nucleophilic displacement of chloro
substituents (in most instances as secondary reactions) appears to involve both
direct (AE) substitution and EA cinesubstitution. With the 2-chloro compound
1,3-telesubstitution occurs as a primary reaction.
A synthesis of enol-lactones
Authors: Ingham CF , Massy-Westropp RA , Reynolds GD , Thorpe WD
Published: December 2006

Several enol-lactones have
been synthesized successfully from the reaction of stabilized phosphoranes with
various substituted succinic and maleic anhydrides. Nuclear magnetic resonance
spectroscopy and chemical interconversions have been used to establish the
stereochemistry of the products. Where both (E) and (Z) isomers were formed the
mixture could be separated readily.
An improved synthesis of 2-(1,1-Dimethylprop-2-enyl)indole
Authors: Russell RA
Published: December 2006

The condensation of aniline
with 1-bromo-3,3-dimethylpent-4-en-2-one yields 2-(1,1-dimethylprop-2-enyl)indole.
1,2,4-Triazol-3-ylpyridines
Authors: Browne EJ
Published: December 2006

A series of N-unsubstituted
1,2,4-triazol-3-ylpyridines was prepared for antiarthritic testing. Weak and
scattered antiinflammatory activity was observed, with no clear
structure-activity relationships. Some of the compounds, notably the
5-pyridyl-1,2,4-triazole-3-carboxylic acids, showed infrared bands
characteristic of strong hydrogen bonding.
Purine studies. XVII. The synthesis of 2-substituted 6,9-Di- and 6,8,9-Tri-methylpurines as amplifiers of phleomycin
Authors: Bhushan K , Brown DJ , Lister JH , Stephanson LG , Yoneda F
Published: December 2006

2-(6?,8?,9?-Trimethylpurin-2?-ylthio)acetamide
(1e) and analogous N- substituted acetamides are prepared by treatment of
6,8,9- trimethylpurine-2-thione (3a) with an appropriate 2- chloroacetamide.
6,9-Dimethyl-2-(piperidin-1?-yl)purine (In) and some 2- polymethyleneamino
homologues are made by initial amination of 2- chloro-4-methyl-6-methylamino-5-nitropyrimidine
(2b) followed by reduction of the nitro group and final cyclization with formic
acid. Such purines enhance the lethal effect of phleomycin on Escherichia coli
cultures.
Cryoscopic and conductance studies of some silicon compounds in disulphuric acid
Authors: Malhotra KC
Published: December 2006

Silicon tetrachloride,
silicon tetraethoxide and silicon tetraacetate are immiscible with disulphuric acid
and there is no interaction between them. Hexamethyldisilane,
ethoxytrimethylsilane, ethoxy.triethylsilane and
trimethylsilanol form trimethylsilicon hydrogensulphate while
triethylmethylsilane forms methyltris(hydrogensu1phate)silane when dissolved in
disulphuric acid. Diethoxydimethylsilane forms dimethylsilicon hydrogensulphate
while triethoxymethylsilane forms methyl silicon trihydrogensulphate. The
solvolysed products have a tendency to form linear or cyclic polymers.Tetraphenylsilicon forms Si
[OSi(HS04)3]4 in disulphuric acid; this also
has a tendency to polymerize in solution. None of these compounds has a
tendency to form H2 [Si(HSO4)6] in disulphuric
acid.
Electrochemical reduction of the nickel(II) dithiocarbamates at the mercury electrode
Authors: Randle TH , Cardwell TJ , Magee RJ
Published: December 2006

The reduction mechanism of
a series of nickel(11) dithiocarbamates has been investigated in dimethyl
sulphoxide at the mercury electrode. Under controlled-potential conditions, the
reduction proceeds initially by an ECE mechanism (electron transfer-chemical
reaction-electron transfer) with n = 1 for both electron transfers. The
chemical reaction involves a dissociation to produce a nickel species more
easily reduced than the nickel(11) dithiocarbamate. However, for some
derivatives, rate constants for the chemical step show a time dependence, at
electrolysis times above 5 s, consistent with an ECCE mechanism of the type
where the product of the first chemical reaction reacts further to produce a
nickel species more difficult to reduce than nickel(11) dithiocarbamate.
Exhaustive reduction of nickel(11) diethyldithiocarbamate at the mercury-pool
electrode gave non-integral n-values (2 > n > 1) consistent with the ECCE
mechanism, and demonstrated that the product of the second chemical reaction is
reoxidized to nickel(11) diethyldithiocarbamate by oxygen. The nature of the
complete electrode reaction suggests a metal-centred reduction.
Thio derivatives of β-diketones and their metal chelates. XXIII. Adducts of nickel(II) chelates of fluorinated Monothio-β-diketones with nitrogen heterocycles
Authors: Livingstone SE , Mayfield JH , Moore DS
Published: December 2006

Paramagnetic adducts of the
nickel(11) chelates of the fluorinated monothio-β-diketones
RC(SH)=CHCOCF3 (R = β-naphthyl, p-ClC6H4, m-ClC6H4, m-BrC6H4, m-MeC6H4, 3,4-Cl2C6H3)
have been obtained with pyridine, y-picoline, 2,2'-bipyridyl, and 1,l0-phenanthroline.
They are of the type NiL2(base)2 (L = RCS=CHCOCF3;
base = py, γpic, �bpy, �phen). With
2,2',2"-terpyridyl two types of adduct were isolated: (a) mononuclear NiL2(trpy) and (b) trinuclear Ni3L6(trpy)2. The infrared spectra of all the adducts
display v(C-O) in the range 1552-1580 cm-l; this band is characteristic
of a bidentate monothio-β-diketonato ligand. The
spectra of the mononuclear terpyridyl adducts display
in addition a v(C=O) band at c. 1650 cm-1, indicating that one
carbonyl group is not coordinated.
Complexes of carbohydrates with metal cations. VII. Lanthanide-induced shifts in the P.M.R. spectra of cyclitols
Authors: Angyal SJ , Greeves D
Published: December 2006

Addition of lanthanide ions
to epi-inositol and related compounds
in aqueous solution causes shifts in their p.m.r. spectra which are interpreted
as being due to diamagnetic, pseudocontact, and contactinteractions. The contact
interactions show stereospecificity: they are greatest when the bonds connecting
the protons to the cation form a planar zig-zag arrangement.
Equilibria between pyranoses and furanoses. IV. 1-Deoxyhexuloses and 3-hexuloses
Authors: Angyal SJ , Bethell GS , Cowley DE , Pickles VA
Published: December 2006

The equilibrium
compositions of 1-deoxy-D-fructose, 1-deoxy-L-sorbose, 1-deoxy-L-psicose, D-threopentulose,
D-arabino-
and L-xylo-3-hexulose and coriose in aqueous solution have been determined by 13C
N.M.R. spectroscopy. In all but the last case, considerable amounts of the
acyclic keto form are present at equilibrium. The hydrated keto form was not
detected; a model compound, l-deoxy- 3,4,5,6-tetra-O-methyl-D-fructose, was found not to be
hydrated in aqueous solution.
Conformational analysis in carbohydrate chemistry. III. The 13C N.M.R. spectra of the hexuloses
Authors: Angyal SJ , Bethell GS
Published: December 2006

All the resonances have
been assigned in the 13C N.M.R. spectra of the hexuloses and some of
their derivatives by the use of specifically deuterated compounds and
comparison with related compounds. The composition of the hexuloses at
equilibrium in aqueous solution has been determined and is discussed in terms
of conformational analysis. The synthesis of D-fructose[l-D], D-fructose[3-D]
and D-fructose[4-D] is described.
Cyclophanes. VI. The synthesis of [2,2](3,3')biphenylparacyclophanedienes
Authors: Jessup PJ , Reiss JA
Published: December 2006

The preparations of
[2,2](3,3')biphenylparacyclophane-1,9-dine (19) and a dimethyl derivative (20)
synthesized by a ring-contraction procedure of the corresponding dithiacyclophanes (11) and (12) are reported. Both dienes (19) and (20) photocyclized
under oxidative conditions to the benzo[ghi]- perylenes (21) and (22).
Difficulties associated with the Stevens rearrangement in cyclophanes containing
a para-disubstituted benzene moiety have been rationalized in terms of a
competing ring- opening reaction. Several other reactions of the biphenylparacylophane ring system are reported, and the
stereochemistry of the macrocycle is discussed.
Copper-catalysed reactions of t-butyl perbenzoate with cis- and trans-p-Menth-2-ene and other cyclic olefins
Authors: Beckwith ALJ , Phillipou G
Published: December 2006

Each of the olefins cis-p-menth-2-ene (23), its trans-isomer (24), 3-methylcyclohexene
(10) and 4- methylcyclohexene (ll), when treated with
t-butyl perbenzoate and cupric octanoate
catalyst in benzene, affords a mixture of allylic
benzoates which can be analysed by gas chromatography after reduction with
lithium aluminium hydride. In most cases the reaction proceeds with a high
degree of stereo- and regio-selectivity, the major products being those
containing a disubstituted double bond and bearing a benzoate group in a trans relationship to an alkyl
substituent. Evidence is presented in support of a free-radical chain mechanism
involving preferential abstraction of allylic
hydrogen atoms occupying quasi-axial positions, followed by ligand transfer
from cupric carboxylate via a cyclic transition state. When catalysed by the bipyridyl complex of cupric octanoate
the reaction is less selective and appears to proceed by a different mechanism.
New Alkaloids of the ent-Kaurene Type From Anopterus Species (Escalloniaceae). I. The Structure and Reactions of Anopterine
Authors: Hart N , Johns S , Lamberton J , Suares H , Willing R
Published: December 2006

Anopterine (1), a major
alkaloid from leaf and bark of Anoptevus
macleayanus F. Muell. and bark of Anoptevus
glandulosus Labill., has an unusual ent-kaurenoid
skeleton with a C20-C14 linkage. Hydrolysis of anopterine gives anopteryl
alcohol (5), C21H31N05, and two equivalents of
tiglic acid. The chemical reactions of anopterine and anopteryl alcohol have
been studied in detail, and a number of acetylation products and oxidation
products have been obtained. Oxidation of anopteryl alcohol with potassium ferricyanide
has given an unusual product (14) which has a C20,C12-oxide bridge and a C5,C6-epoxide
group.
New Alkaloids of the ent-Kaurene Type From Anopterus Species. II. The Structure of the Minor Alkaloids
Authors: Hart N , Johns S , Lamberton J , Suares H , Willing R
Published: December 2006

Anopterimine (2) is a new diterpenoid alkaloid, and on the basis
of spectroscopic data it is considered to have the same carbon skeleton as anopterine. It is remarkable in having a C19-N azomethine system, while another minor base of A. macleayanus is
anopterimine N-oxide
(3). Two other new alkaloids, hydroxyanopterine and dihydroxyanopterine, both resemble anopterine,
and spectroscopic data indicate that they have an additional hydroxy group at
C1 or C3 on the A ring. Dihydroxy- anopterine has tiglic acid and the new acid,
(E)-4-hydroxy-2-methylbut-2-enoic acid, as esterifying
acids. A biosynthetic route to the Anopterus
alkaloids is suggested.
Chemical constituents of Harpullia pendula
Authors: Khong PW , Lewis KG
Published: December 2006

From the methanol extract
of the bark of Harpullia pendula Planch. there have been isolated the known compounds Al-barrigenol, camelliagenin A, 22α-hydroxyerythrodiol
and methyl p-coumarate. The structures of three new triterpenes were assigned as A1-barrigenol 22-angelate
and camelliagenin A 16- and 22-angelate.
The thermal decomposition of acetyl chloride
Authors: Stimson VR , Tilley JW
Published: December 2006

At 242.4-350 3° the equilibrium
CH3COCl 𘄤 CH2CO + HCI
is established with (Kp in atm)
8.314 ln Kp = -100300/T+ 132.9
Rate constants for the reactions are given by the Arrhenius equations:
k1 (s-1) = 1012.42 exp(-168900/8.314T) (measured)
k2 (s-1 ml mol-1) = 1010.27 exp(- 69900/8.314T) (calculated)
The van't Hoff equation leads to ΔH°f,298,g = -61.0 kJ mol-1 for ketene.
At 299-491° the decarbonylation
CH3COCl → CH3Cl + CO
also takes place and it is compared with other similar reactions.
The nitration of substituted ethylbenzenes and substituted biphenyls
Authors: Clemens AH , Hartshorn MP , Richards KE , Wright GJ
Published: December 2006

Nitration occurs ipso to
the ethyl group for p-ethyltoluene, p- diethylbenzene and ethylmesitylene. No
evidence was found for ipso- nitration for 2,4,6-trimethyl-, 4-methoxy-,
4-bromo- and 2,2',4,4',6,6'-hexamethoxy-biphenyls.