bluuebunny/crossref_metadata_2025 huggingface dataset:
The reactions of aromatic Schiff bases with dimethyl acetylenedicarboxylate. I. Reaction in an organic solvent
Authors: Murphy ST , Taylor WC , Vadasz A
Published: September 2010

Reaction
of benzylideneanisidine with dimethyl acetylenedicarboxylate in refluxing xylene/nitrobenzene gave
low yields of a bis-adduct, the dihydropyridine
(12), and two dehydro adducts-the quinolines
(13a) and (14). Anisylideneaniline under similar
conditions gave the dihydropyridine (16) and an
'abnormal' bis-adduct. Benzylideneaniline gave only an 'abnormal' bis-adduct.
The reactions of aromatic Schiff bases with dimethyl acetylenedicarboxylate. II. Reaction in the presence of water
Authors: Taylor WC , Vadasz A
Published: September 2010

The
reaction of benzylideneaniline with dimethyl acetylenedicarboxylate in the
presence of water has been re-examined. The structure previously proposed for
the product was found to be incorrect. The product is shown to be methyl 4-hydroxy-5-oxo-1,2-diphenyl-3-pyrroline-3-carboxylate
(3). Similar
products were obtained from benzylideneanisidine and anisylideneaniline.
Pyrimidine N-oxides. V. Ionization constants of N-hydroxybarbiturates
Authors: Cowden WB , Jacobsen NW , Stunzi H
Published: September 2010

The ionization constants, pKa,
of a number of N-hydroxy
5-substituted barbituric acids and their O-and N-alkylated
derivatives are reported. For practical comparisons under physiological
conditions, pKa values were also
determined at I 0.15 M KNO3
and 37� for the clinically useful barbiturates metharbital,
phenobarbital and veronal,
and for their mono-N-hydroxy derivatives. The pKa values for N,N?-dihydroxyphenobarbital
and the corresponding veronal were also measured.
Improved synthesis of 2,10-dioxatricyclo[4,4,4,01,6]tetradecanes
Authors: Down GJ
Published: September 2010

Cyanoethylation
of substituted cyclohexanones at low temperatures has
been found to give markedly improved yields and regioselectivity
over the usual conditions for the Michael reaction. This reaction greatly
facilitated the preparation of the 2,10-dioxatricyclo[4,4,4,01.6]tetradecanes
(1). Carbon-13 n.m.r. data are reported for several
substituted ketone and acetal intermediates and for the tricyclic
acetal product (1b).
Colouring matters of the Aphidoidea. XLV. Synthesis of (±)-deoxyquinone A dimethyl ether and its epimer (±)-cis-7,9-Dimethoxy-1,3-dimethyl-3,4,5,10-tetrahydro-1 H-naphtho[2,3-c]pyran-5,10-dione [(±)-7-Methoxyeleutherin]
Authors: Cameron DW , Feutrill GI , Pietersz GA
Published: September 2010

(�)-Deoxyquinone A dimethyl ether (1) has been synthesized from
5,7-dimethoxy-1-naphthol. This
is the first synthesis of an aphin-derived pyranonaphthoquinone, the (+)-enantiomer
having been obtained from natural sources. The (�)-cis epimer
(3),7-methoxyeleutherin, a plant product, was also obtained for the first time.
Synthesis of some arylated quinones
Authors: Cameron DW , Feutrill GI , Patti AF , Perlmutter P , Sefton MA
Published: September 2010

1,3-Dihydroxy-2-phenylanthraquinone has
been synthesized by reaction of 2-phenylacetyl-1,4-naphthoquinone with
1,1-dimethoxyethene and subsequent intramolecular condensation. It has also
been obtained by Diels-Alder cycloaddition. Some arylated benzo-and naphtha-quinones
have been synthesized by the Meerwein reaction.
Tritium labelling and tritium N.M.R. II. Labelled methyl (Z)-Octadec-9-enoate obtained by partial hydrogenation on Lindlar catalyst, and its reduction to(Z)-Octadec-9-en-1-ol
Authors: Odell AL , Ronaldson KJ , Martin RW , Calvert DJ
Published: September 2010

The selectivity of tritium labelling of double bonds by partial hydrogenation of the acetylenic analogue on Lindlar
catalyst is investigated by 3H and 13C n.m.r. Examples of
both the secondary isotope effect on chemical shift and the usefulness of 3H
n.m.r, measurements to calculate proton-proton coupling constants are
described. In the absence of proton coupling a finite difference (0.014 ppm) in the chemical shift of tritons at positions 9 and 10
of methyl (Z)-[9,10-3H]octadec-9-enoate is observed.
Ion-ion-solvent interactions in solution. II. Solutions of LiClO4 in diethyl ether
Authors: James DW , Mayes RE
Published: September 2010

.Vibrational spectra and 35Cl, 13C, 7Li and 1H n.m.r. spectra of anhydrous solutions of LiClO4 in
diethyl ether have been studied. There is no evidence for the formation of free ions down to 0.1 M
concentration of salt. Two salt species having concentration-dependent distributions are identified,
these being contact ion pairs and ion aggregates. The salt species are solvated with one mole of
solvent per mole of salt. The preferred conformation of the diethyl ether solvate molecule is
trms-gauche. For pure dlethyl ether at 25°C the trans-trans → trans-gauche equilibrium has
ΔH 5.85 kJ mol-1 and ΔS 19.5 J K-1 mol-1. The ΔH value is not influenced by the presence of
salt, but ΔS increases as the salt concentration increases until at 4 M LiClO4 the value is 37.6 J K-1
mol-1.
The crystal structure of (S)-( - )-6-Bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one [( - )-6-bromocryptostrobin] and a 13C N.M.R. study of (±)-cryptostrobin and related substances. Revision of the structures of the natural products (±)-lawinal, unonal, 7-O-methylunonal and isounonal
Authors: Byrne LT , Cannon JR , Gawad DH , Joshi BS , Skelton BW , Toia RFWAH
Published: September 2010

The crystal structure of
(S)-(-)-6-bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one
[(–)-6-bromocryptostrobin] (11) has been determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal
least squares to a residual of 0.050 (810 'observed' reflections). Crystals of
(11) are tetragonal, P43212, a 7.849(4), c 46.83(2) �,
Z 8. The crystallographic data are consistent with the S configuration
previously proposed for (–)-cryptostrobin (10). The 13C
n.m.r, spectra of (�)-cryptostrobin and(�)-strobopinin also lead to the structures (1) and (6),
respectively. This work has enabled the structures proposed for the natural
products (�)-lawinal, unonal,
7-O-methylunonal and isounonal to be
revised to (8), (14), (15) and (12), respectively.
Transition-metal mediated asymmetric synthesis. IV. Chelation of malonate esters by a chiral lanthanide shift reagent: a general method to measure theenantiomeric excess of tricarbonyl(cyclohexadienyl)iron(1+) salts
Authors: Stephenson GR
Published: September 2010

Chelation
of dimethylmalonate derivatives of variously
substituted tricarbonyl(cyclohexadienyl)-iron(1+)
salts by tris(3-trifluoroacetyl-(+)-camphorato)europium(III) successfully
resolved the methoxy resonances due to the two epimers of the cyclohexadiene complexes
in the 1H n.m.r. spectra of racemic samples. The method provides a
general means to measure enantiomeric excess of
tricarbonyliron
complexes.
Crystal structure of (±)-2-[4-(4-chlorophenoxymethyl)phenoxy]propionic acid
Authors: Smith G , Kennard CHL , Duax WL , Swenson DC
Published: September 2010

The crystal structure of (�)-2-[4-(4-chlorophenoxymethyl)phenoxy]propionic acid has been
determined by direct methods using three-dimensional X-ray diffraction data.
The crystals are triclinic, P1, Z 2, a 9.345(2),
b 12,602(2), c 6.741(1) �, α 101.37(1), β 97.42(1), γ 101.75(1)�.
The structure refined to give a final R 0.084 for 2172 observed reflections.
The acid molecules form centrosymmetric hydrogen
bonded cyclic dimers [O. . .O,2.619(4) �] about a centre of symmetry in the
cell. The oxopropionic acid side chain has a synplanar-synplanar
(carbonyl) conformation while the planar p-chlorophenoxymethyl substituent in the p-position has a synclinal orientation relative to the primary phenoxy residue.
The chemistry of pyrrolic compounds. LII. The preferred pathway of electron delocalization in metalloporphyrins
Authors: Chakraborty S , Clezy PS , Sternhell S , van Thuc L
Published: September 2010

Measurement of the proton coupling
constant in the allylic unit, CH3-C=C-H,
of the zinc(II), nickel(II) and magnesium(II) chelates of the deuteroporphyrin isomer (3a) points in each case to the
double bond of this system having a significantly diminished bond order.
Similar data have been obtained for the dication
derivative of (3a). These findings are in accord with the view that the π-electron delocalization pathway in porphyrin dications and metalloporphyrins
involves the periphery of the molecule as was previously shown for the
metal-free porphyrin. New synthetic approaches to the porphyrin (3a) have been
studied.
Electrochemical studies of amine salts of monothiocarbamates
Authors: Magee RJ , Annuar B
Published: September 2010

The electrochemical
behaviour of the amine salts of morpholyl-, pyrrolidyl-�and piperidyl-mono- thiocarbamates (morpholinium morpholine-4-carbothioate, piperidinium
piperidine-1-carbothioate and pyrrolidinium
pyrrolidine-1-carbothioate) at the mercury electrode has been studied by means
of d.c. polarography and
cyclic voltammetry. All three exhibited a well
defined anodic wave, but the pyrrolidyl derivative (pymtc) gave an additional wave. The main wave in each case
was found to be diffusion-controlled. Temperature coefficients showed erratic
behaviour at higher temperatures which was thought to be due to decreasing
availability of reactive material because of decomposition. Controlled
potential coulometry gave n = 1 per mole for the main wave of each compound. The behaviour
was similar to that of the dithiocarbamate ligands
under the same conditions and the small pre-wave in the polarograms
of pymtc is attributed to the formation of a mercuric
pyrrolidyl monothiocarbamate,
which, unlike the mercuric complex of the other two ligands is structurally
ordered and able to form a compact layer with the electrode. Cyclic voltammetric results supported the findings of polarography and confirmed the following mechanism:
mtc- + Hg →
Hg(mtc) + e' (1)
2Hg(mtc) → Hg(mtc)2
+ Hg (2)
The reactions of alkoxide-alkanol negative ions with carbonyl compounds. An ion cyclotron resonance and ab initio study
Authors: Klass G , Sheldon JC , Bowie JH
Published: September 2010

Simple
alkyl aldehydes, ketones and esters containing the unit >:
CH-CO-react with alkoxide-alkanol
negative ions [RO----HOR] to form stable [M+RO-] negative
ions (neutral denoted by M). The initial
intermediate in the reaction sequence is produced by the formation of a
hydrogen bond between the negatively charged oxygen of [RO----HOR]
and the hydrogen of the > >CH-CO-
unit. This intermediate decomposes to
the stable product ion by
two reaction
sequences: (i) by direct elimination of ROH, and (ii)
by rearrangement to a decomposing 'doubly-solvated' negative ion in which the
central hydrogen of [RO----HOR] and
the
hydrogen of the >CH-CO unit become
identical. As both reaction pathways are complex, all intermediates and certain
transition states have been properly defined by using ab initio calculations at the 4-31G level.
Reactions of propargyl alcohols. V. Lithium aluminium hydride reduction of some C 1-epimeric 4-t-butyl-1-prop-1'-ynylcyclohexanols
Authors: Blunt JW , Hartshorn MP , Soong LT , Munro MHG
Published: September 2010

The preparation and lithium
aluminium hydride reductions of C1-epimeric 4-t-butyl-1-prop-1'-ynyl- cyclohexanols (8) and (9), and their 2-methyl (10) and (11)
and 2,6-dimethyl(12) and (13) derivatives are described. The effects of solvent
and substrate structure on the reductions are discussed.
A fluorochrome from aniline blue: structure,synthesis and fluorescence properties
Authors: Evans NA , Hoyne PA
Published: September 2010

A fluorochrome has been
isolated in analytically pure form from a commercial sample of the triaryl-methane
dye aniline blue. Its structure has been shown to be sodium
4,4'-[carbonylbis(benzene-4,1-diyl)bis(imino)]bisbenzenesulfonate by
spectroscopic means and confirmed by synthesis. Its fluorescence emission,
which is markedly solvent-dependent, is 150 times greater in butan-1-ol than in
water (however, the wavelength of the emission maximum is not altered
significantly). In the presence of a cationic surfactant,
hexadecyltrimethylammonium bromide, the fluorescence intensity reaches a
maximum at approximately the critical micelle concentration of the surfactant.
New aromatic sesquiterpenes from a Halichondria sp
Authors: Capon RJ , Ghisalberti EL , Jefferies PR
Published: September 2010

Three
new aromatic sesquiterpenes have been isolated from a Halichondria sp, found off the Western Australian
coast. Evidence is presented for the structure of (1'Z)- and (1'E)-2-(1',5'-dimethylhexa-
4'-dienyl)-5-methylbenzene-1,4-diol and
of (1'E)-2-(1',5'-dimethylhexa-1',4'-dienyl)-5-methyl-phenyl
acetate.
Equilibrium partial pressures over (NH4)2SO4/H2SO4 mixtures
Authors: Ayers GP
Published: September 2010

A currently available
description of vapour/condensed-phase equilibrium for
mixtures of (NH4),SO4 and H2SO4 is
revised to include new experimental data and an additional equilibrium
relation.
Synthesis and molecular structure of tetraphenylarsonium Tetrakis(benzenethiolato)-oxorhenate(V)-Acetonitrile (1/1)
Authors: McDonell AC , Hambley TW , Snow MR , Wedd AG
Published: September 2010

The salts Ph4As
[ReO(SPh)4].MeCN and Ph4As [ReO(SePh)4] have been synthesized and characterized.
The crystal and molecular structure of the thiolate
compound has been determined by X-ray crystallography which reveals a
square-pyramidal arrangement of ligand atoms around the central rhenium atom of
the [ReO(SPh)4]-
anion. Crystal data: a 9.756(4), b 18.171(3), c 25.684(4) �, space group P212121,
Z 4.
Applications of the intermolecular nuclear Overhauser effect. I. Determination of differential solvent effects: the hydration of pyridine
Authors: Smith GR , Ternai B
Published: September 2010

The intermolecular
relaxation rates of the pyridine-water system have been obtained by the measurement
of the total spin lattice relaxation rate and the intermolecular nuclear Overhauser effect between pyridine and water, for each
pyridine proton. The advantages of this method for the determination of the
intermolecular relaxation rates are discussed, and the method is compared with
alternative methods. The results indicate that there is a varying degree of
hydration about the pyridine molecule, with the nitrogen being the preferred
site of water interaction. It is necessary to interpret the results in terms of
solute-solute as well as solute-solvent interactions. A model is proposed which
takes account of both types of interaction, and is considered in terms of
previously proposed models of pyridine-water interactions.
Reactions of propargyl alcohols. VI. Lithium aluminium hydride reductions of 2,2-Dimethyl-3-phenylhex-4-yn-3-ol, its 1-methoxy derivative and 2,2-Di-(methoxymethyl)-3-phenylhex-4-yn-3-ol
Authors: Blunt JW , Hartshorn MP , Munro MHG , Lee T , Thompson RS , Trebilco PR , Vannoort RW , Vaughan J
Published: September 2010

Lithium aluminium hydride
reductions of 2,2-dimethyl-3-phenyIhex-4-yn-3-ol (5a) and its methoxy (5b) and
dimethoxy (5c) derivatives are reported. The nature of the solvent dependence
of these reactions is identified, and the mode of formation of the products of
the reactions determined.
Synthesis of analogues of GABA. VIII. Selective a-alkylation and γ-halogenation of the dianion from α,β-unsaturated nipecotic acid derivatives
Authors: Allan RD , Fong J
Published: September 2010

1,2,3,6-Tetrahydropyridine-3-carboxylic
acid (3), the β, γ-unsaturated derivative of the GABA uptake
inhibitor nipecotic acid (1), has been synthesized by
deconjugation via the dilithium
salt of the N-t-butyloxycarbonyl-protected
intermediate (6). Substitution of the intermediate with alkylating
agents or an aldehyde gave predominantly a-alkylated products but chlorination with N-chlorosuccinimide provided a route to
the γ-substituted unsaturated amino acid (13a).
The preparation and 1H n.m.r. spectra of some N-methylpurines and related compounds
Authors: Barlin GB , Fenn MD
Published: September 2010

A 1H n.m.r.
study of some methoxy-, methylthio- and chloro-N-methyl-purines and
imidazo[4,5-c]-pyridines revealed that the signal due to the N-methyl group when present in the
six-membered ring occurred at lower field than when present in the imidazole ring. The methylation of 2-,6-and 8-methoxypurines
with diazomethane, and metatheses of chloro-N-methylpurines each to methoxy-N-methylpurines
are described.
Viscosity and tracer diffusion coefficients, and thermodynamic properties, for ethanol + acetonitrile mixtures at 298.15 K
Authors: Easteal AJ
Published: September 2010

Molar volumes and partial
molar volumes, tracer diffusion coefficients (D), and shear viscosities (η)
are reported for ethanol + acetonitrile mixtures at
298.15 K. The tracer diffusion coefficients vary non-additively with
composition, and the product Dη for each
component is composition-dependent. Albright's equation for viscosity
reproduces experimental viscosities to within the combined uncertainties of the
experimental data. The system exhibits considerably less complex behaviour than
does the analogous water + acetonitrile system, and the properties are thought
to be dominated by dipole-dipole interactions between unlike molecules.
Crystal and molecular structure of Octacarbonylbis(diphenylarsino)-methanedimanganese(0)
Authors: Hoskins BF , Steen RJ
Published: September 2010

The crystal structure of
the complex Mn2(CO)8(dam) (dam = Ph2AsCH2AsPh2)
has been determined by three-dimensional X-ray diffraction methods. The
crystals are triclinic, space group P1, with a 11.191(1), b 16.498(5),
c 9.455(1) �, a 93.64(2), β
109.08(2), γ 89.36(2)� and contain two discrete, binuclear molecules of Mn2(CO)8(dam)
per unit cell. The structure, solved by direct and Fourier methods, was refined
by a least-squares procedure to R and Rw
of 0.065 and 0.082 respectively for 1907 independent, statistically significant
reflections collected by counter methods. The feature of particular interest in
this compound is the accommodation of the bridging bidentate dam ligand [As..
.As separation 3.242(2) �] across a shorter Mn�-Mn�
bond [2.962(3) �] which constrains the molecule so that a much less staggered
configuration of the two manganese coordination octahedra
is observed relative to the parent compound Mn2(CO)10,
the rotation of the two equatorial planes in the former being 30�.
The synthesis of perloline, 6-(3,4-Dimethoxyphenyl)-5-hydroxy-5,6-dihydrobenzo[c]-[2,7]naphthyridin-4(3H)-one
Authors: Prager RH , Were ST
Published: September 2010

Dehydroperloline is obtained in high overall yield by an
intramolecular cyclization of the benzyne generated
from 4-(2-bromophenyl)-N-(3,4-dimethoxyphenyl)-2-oxo-1,2-dihydropyridine-3-carboxamide
(21), by use of lithium hexamethyldisilazide. A benzyne intermediate has not been established. The pyridinone (21) was prepared in three steps from
2-[1-(2-bromophenyl)ethylidene]malononitrile.�Dehydroperloline
was smoothly reduced by sodium bis(methoxyethoxy)aluminium
hydride to perloline, isolated as its hydrochloride.
Transfer activity coefficients between some dipolar aprotic solvents and alcohols of salts composed of various anions and potassium complexed with Bis(4,4'(5')-t-butylbenzo)-18-crown-6
Authors: Chantooni Jr MK , Kolthoff IM , Roland G
Published: September 2010

Stability constants, Kf(LK+) and Kf(LKX)
= [LKX]/[L][KX] at 25� in the dipolar aprotic
solvents acetone (Me2CO), acetonitrile (MeCN), propylene carbonate (pc), N,N-dimethylformamide (HCONMe2), dimethyl sulfoxide (Me2SO),
as well as in the alcohols, methanol (MeOH),
isopropyl alcohol (Pr1OH), and butan -1-ol
(BuOH) have been determined, L being
bis(4,4'(5')-t-buty1benzo)-18- crown-6 (di(BuBo)-18-cr-6).
This crown is considerably more lipophylic than is
dibenzo-18-crown-6. Values of Kf(LKX) have
been found from values of Kf(LK+),
KA(KX) and KA(LKX). Transfer activity coefficients, Me2COγS,
have been calculated (based on the Parker proposal that γ(Ph4As+)
= γ(BPh4-) between acetone and the various solvents used of K+,
Br-, ClO4-, P1- (picrate), LK+, KX, and LKX. It is found that K+
is more strongly solvated in Me2CO than in the other aprotic solvents of low donicity.
The reverse is true between Me2CO and HCONMe2 or Me2SO
(even after correcting for the Born effect).
X-ray photoelectron spectroscopic investigation of the tarnishing of bornite
Authors: Buckley AN , Woods R
Published: September 2010

Changes in the surface
composition of natural bornite after prolonged
exposure to the atmosphere have been studied by X-ray photoelectron
spectroscopy. Freshly cleaved surfaces oxidize rapidly, producing a hydrated
iron oxide and a copper sulfide; as tarnishing proceeds, the iron oxide segregates
to the surface forming an over-layer of uneven thickness on the copper sulfide.
The tarnish is usually close to its limiting thickness after about two days and
its thickness and composition are such that a purple colour
is produced. Although surfaces often maintain this appearance for at least a
year, blue patches may develop after between one and two days of exposure. Blue
surfaces have also been observed when the mineral is cleaved along an existing
interface. Copper(II) has been found to be present at all blue surfaces
investigated. Silver, which exists as a minor element in the mineral, becomes
concentrated in the tarnish layer where it is present in the copper sulfide
component.
Electron-transfer reactions in non-aqueous media. VII. Reduction of CoF(NH3)52+ and Co(HCOO)(NH3)52+ by copper(I) in dimethyl sulfoxide-water mixtures
Authors: Harrowfield JMB , Spiccia L , Watts DW
Published: September 2010

Previous work on the reduction of a series of cobalt(III) complexes by iron(II) in dipolar aprotic
solvents and in aqueous mixtures has been extended to reduction by copper(I). The greater stability
of copper(I) to disproportionation in these media has permitted the study of the reduction of
CoF(NH3)52+ and Co(HCOO)(NH3)52+ in range of solvents over a number of temperatures with
a precision not possible in previous studies in water.
The results are consistent with an inner-sphere mechanism in which the copper(I) reductant is
preferentially solvated by dimethyl sulfoxide to the exclusion of water in mixed solvents.
Reactions in mixed non-aqueous systems containing sulfur dioxide. V. The formation of metal sulfur oxyanion compounds by the electrolytic solution of metals
Authors: Graham NK , Gill JB , Goodall DC
Published: September 2010

The metals Ti, Zr, V, Cr, Mo, Fe, Ni and Sn dissolve electrolytically in the binary solvent system
dimethyl sulfoxide-sulfur dioxide, forming metal disulfates; W forms sulfate. The metals dissolve
electrolytically in other binary systems containing sulfur dioxide, forming mixtures of sulfur
oxyanions. The importance of solvent parameters in metal reactivity is discussed, together with
the mechanism of the reactions.
The crystal and molecular structure of picrotoxinin
Authors: Mackay MF , Sadek M
Published: September 2010

X-ray analysis has defined the conformational detail in crystals of picrotoxinin, C15H1606. Crystals
are monoclinic: space group PZ1, a 7.719(1), b 12.004(3), c 14.693(4), Ǻ β 98.06(1)7#176; and Z 4.
The structure was solved by direct methods with diffractometer data measured with Cu Kα radiation.
Refinement converged at R 0.037 for the 2220 observed terms. The two molecules in the asymmetric
unit have essentially identical conformations consistent with one of the two alternative low energy
conformations deduced from classical potential energy and molecular orbital calculations.
Synthesis and characterization of some S,S-Dimethyl-N-pyrimidinylsulfimides
Authors: Hurst DT
Published: September 2010

A convenient synthesis of several S,S-dimethyl-N-pyrimidin-2 4-ylsulfimides is described. The
compounds were characterized by n.m.r., mass spectral and elemental analyses.
Reactions of cyclohexenyl halides with tributylstannane. Stereoelectronic effects on SH2 reactions at halogen
Authors: Beckwith ALJ , Westwood SW
Published: September 2010

Allylic halogenation of t-butylcyclohexene (2a) with t-butyl hypochlorite or
N-bromosuccinimide affords mixtures containing mainly trans-5-t-butyl-3-chlorocyclohexene (2b) and the corresponding trans bromo compound (2c) respectively.
The copper-catalysed reaction of (2a) with t-butyl perbenzoate
shows similar but less pronounced stereoselectivity. Halogen-atom abstraction
by tributyltin radicals, generated from tributylstannane,
proceeds more rapidly from the trans
halides (2b) and (2c) than from their cis
epimers (3b) and (3c). These results suggest that homolytic fission or formation of allylic C-halogen bonds
is sensitive to stereoelectronic effects.
Basic hydrolysis of some alkyl and phenyl N-Aryl-N-methylcarbamates
Authors: Broxton TJ
Published: September 2010

Rate constants for the
basic hydrolysis of methyl, ethyl and phenyl N-aryl-N-methylcarbamates in the presence and absence of micelles of
cetyltrimethylammonium bromide are reported. Hammett plots for the methyl and
ethyl carbamates were curved, and this is explained by consideration of the
competition between C-N and C-OR bond breaking for decomposition of the
tetrahedral intermediate. In one case (p-nitro-substituted), rate-determining
formation of the tetrahedral intermediate is suggested, whereas for other
compounds rate-determining C-N bond breaking or C-OR bond breaking is proposed.
Micellar catalysis for each of the reactions is reported, and large catalysis
(× 50) was observed for compounds where C-N bond breaking was kinetically
significant. This is compared with results in the literature for amide and
ester hydrolysis. Whereas, for ester hydrolysis, loss of alkoxide
ion from the tetrahedral intermediate is favoured over loss of hydroxide ion,
in carbamate hydrolysis, loss of hydroxide ion is favoured. A possible reason
for this reversal of nucleofugicity of OH- and OR- is
proposed.
The basicities of aliphatic amides
Authors: Grant HM , Mctigue P , Ward DG
Published: September 2010

We report pKa
values in aqueous solution at 298 K of the protonated forms of several
aliphatic amides, viz., acetamide (pKa = -0.62
� 0.07), N-methylacetamide
(-0.42 � 0.03), N,N-dimethyl-acetamide (-0.28 � 0.03), N,N-dimethylformamide (-1.2 + 0.5), urea (0.053 � 0.002) and thiourea (-0.9 � :O.l). pKa
values are also reported for protonated acetamide and
urea in aqueous solution in the temperature range 5-40�C and in D2O.
A previously described conductimetric method was used
for all measurements.
The separation of substituted Olean-12-en-28-oic acids from the corresponding Urs-12-en-28-oic acid isomers
Authors: Lewis KG , Tucker DJ
Published: September 2010

Naturally occurring pairs
of hydroxy-substituted olean-12-en-28-oic and urs-12-en-28-oic acids may be
separated by treatment of the mixture with bromine in acetic acid. Members of
the ursene family are inert under the conditions
used. It is shown that a similar separation is possible with the 12-en-28-ol
system. The leaf of Duboisia myoporoides
was examined for possible variation of ursolic acid
content with location.
Solvent effects on the reaction of t-butoxy radicals with methyl methacrylate
Authors: Grant RD , Griffiths PG , Moad G , Rizzardo E , Solomon DH
Published: September 2010

Examination of the title
reaction in a range of solvents shows that the ratio of hydrogen abstraction to
t-butoxy radical addition increases with increasing solvent polarity. In
several cases there is a competition between solvent and methyl methacrylate for
reaction with t-butoxy radicals. The implications of these findings for polymer
structure are discussed.
Effects of pressure on the infrared spectra of some heterocyclic organosilicon and organogermanium compounds
Authors: Hamann SD , Mazerolles P , Faucher A , Manuel G
Published: September 2010

Measurements have been made
of the infrared spectra of eight solid heterocyclic organosilicon and
organogermanium compounds at pressures up to 5 GPa at normal temperature.
Evidence is found of reversible conformational changes under pressure, and of
phase transitions in some of the compounds. Unexpectedly, it appears that
compression does not favour the transannular interaction that exists, in some
cases, between the heteroatom (silicon or germanium) and a functional group on
the opposite side of the ring.
Nitrones and Oxaziridines. XXIX. Synthesis and reactions of 2,3-Diaryl-1-pyrroline 1-oxides
Authors: Black DSC , Johnstone LM
Published: September 2010

The 2,3-diaryl-1-pyrroline
1-oxides (5) and (6) have been prepared, together with the related pyrrolines
(7) and (8). The nitrone (5) undergoes reaction with benzoyl chloride to give
the 2H- pyrrole (17) and the pyrroline (18) and nitric acid oxidation of (5)
gives the oxo nitrone (21). Both nitrones (5) and (6) react with N-bromosuccinimide to give the
2H-pyrrole 1-oxides (19) and (20) respectively. Ultraviolet irradiation of (5)
and (6) give initially the oxaziridines (22) and (23) which undergo ring-contraction
to the azetidines (24) and (25), which could not be obtained pure. On attempted
purification, compound (25) was converted into the amide (26). The pyrroline
(7) was converted in boiling n-hexane into the stable hydroperoxide (9), which
was reduced to the hydroxy- pyrroline (15), also derivable from the pyrroline
(18).
Nitrones and oxaziridines. XXX. Double ring cleavage of bicyclic oxaziridines by iron(II) sulfate
Authors: Black DSC , Johnstone LM
Published: September 2010

The hydroxy oxaziridines
(7), (10), (13), (16) and (23) have been converted by iron(11) sulfate into the
respective amides (8), (11), (14), (17) and (24). The oxaziridines were
generated from the corresponding I-pyrroline 1-oxides (6), (9), (12), (15) and (22)
and in some cases were not characterized but converted directly into the
amides. Two isomers of oxaziridine (7) were isolated,
only one of which was formed in the peracetic acid oxidation of the pyrroline
(5). The oxaziridine (23) was isolated and characterized
as a mixture of two isomers.
Organophosphorus chemistry. III. Synthesis of 3-Ethoxy-2-phenyl-1,3-azaphosphininane 3-oxide
Authors: Hewitt DG , Teese MW
Published: September 2010

Treatment of ethyl
(3-bromopropyl)phosphonochloridate with benzylmagnesium chloride gave ethyl (benzyl)(3-bromopropyl)phosphinate.
This underwent free-radical bromination to give ethyl
(a-bromobenzyl)(3-bromopropyl)phosphinate Cyclization with aqueous ammonia gave
3-ethoxy- 2-phenyl-1,3-azaphosphininane 3-oxide. Attempts to prepare the
2-(pyridin-3'-yl)-substituted 1,3-azaphosphininane are also discussed.
Crystal and molecular structure of [IrH3(Pme2Ph)2]2 : a novel (μ-H)2 bridged IrIII dimer
Authors: Robertson GB , Tucker PA
Published: September 2010

The preparation and
characterization of the title compound are described. Crystals are
orthorhombic, space group Pbca, with a
11.433(5), b 14.768(6), c 20.616(10) � and Z 4. Diffraction data
were recorded on a four-circle diffractometer. Least-squares analyses converged
with R = 0.038 for 1897 unique data. Molecules are (pH), bridged dimers possessing strict crystallographic inversion
symmetry. Metal atoms have a formal 16e- configuration and are
approximately octahedrally coordinated by four H (two
bridging) and two phosphine ligands. The Ir-Ir
distance [2.739(1) �] is intermediate between those in (�-H)(�-Cl) and (�H)3
bridged species. Ir-P distances [2.231(3) and 2.3132)
�, trans to bridging and terminal H
atoms respectively] show the trans-influence
of bridging H to be small, cf. terminal H. Molecules exhibit fluxional
behaviour in solution.
Carbon-13 N.M.R. shifts as a measure of transannular interaction in unsaturated alicyclic systems
Authors: Bishop R
Published: September 2010

Through-space transannular
interaction between formally non-conjugated methylene and carbonyl n-electrons
in conformationally rigid 3,7-disubstituted
bicyclo[3.3.1]nonanes (1) has been demonstrated by Senda et al.
by comparing the 13C n.m.r. shift values of the sp2
atoms. This procedure has been extended successfully to include conformationally mobile benzo
derivatives (2) of bicyclo[3.3.2]decane and
1,5-disubstituted cyclooctanes (4). It also succeeds
for 5,7-disubstituted derivatives (3) of 1,2,4-ethanylylidene-1H-cyclobuta[cd]pentalene where through- bond
interaction is known to be involved. The method is concluded to be a general
and reliable one for detection of transannular π-electron delocalization and to have potential in
prediction of intramolecular cyclizations.
Possible heterocyclic ions in the reaction zones of flames with added nitrogen or sulfur
Authors: McAllister T
Published: September 2010

Ions of m/z 80 and 94 are
observed in the reaction zone of a C6H6/N2O/H2
flame, by flame ionization/mass spectroscopy. These are confirmed, by deuteration, as protonated
pyridine and aniline. These ions are also detected in the reaction zone of a CH4/N2O
flame, along with ions of m/z 44, 56, 68 and 72, which, it is proposed, are
formed by protonation of the heterocyclic species aziridine,
dihydroazete, pyrrole and pyrrolidine. This series of
N-containing ions is in keeping with the postulate that HCN is formed in flames
of hydrocarbons and N-compounds, and that the associated CN radicals undergo
addition and hydrogenation reactions. Cyano compounds
are not, however, detected, because their proton affinities tend to be lower
than that of NH3. In a C6H2/CS2/H2
flame, a series of S-containing ions are observed, beginning at m/z 97, for
which the thiopyrylium structure is proposed. The
detection of this stable aromatic species is in contrast to the absence of protonated thiophene. It is
postulated that the active S-containing species in this flame is CS.
Kinetic studies on the effect of acidity and temperature on the loss of optical activity of some butanediols
Authors: Herlihy KP
Published: September 2010

In aqueous perchloric acid, butane-1,2-diol (1) and butane-2,3-diol
(2) give carbonyls and butane-1,3-diol (3) gives alkenols.
The rate of loss of optical activity has been determined for these diols and butan-2-ol (4) over a range of temperatures and
acidities. In 1 M acid at 100�C, the rates for (1), (2), (3) and (4) are in the
ratio of 1 : 2.3 : 3.7 : 45 respectively. The activation parameters are similar
for all the alcohols. Hammett acidity plots give slopes of c. 0.8 for the diols and of 1 for butan-2-ol. These variations in these
kinetic parameters are discussed in terms of whether hydroxyl group
substitution in butan-2-ol affects the mechanism of its reaction in these
circumstances.
Reaction of γ-nitro ketones with thionyl chloride: formation and X-ray crystal structure of an α-sulfinyl ketone
Authors: Black DSC , Fallon GD , Gatehouse BM , Wishart JD
Published: September 2010

Reaction of thionyl
chloride on 4-methyl-4-nitro-1-phenylpentan-1-one (2) yields 4-methyl-4-nitro-
1-phenyl-2-thioxopentan-1-one S-oxide (4), the structure of which has been
clarified by X-ray crystallography. The corresponding methoxyphenyl compound
(10) has been obtained similarly. The sulfinyl ketone (4) underwent base
hydrolysis to the methylene ketone (2) and photoconversion into the diketone
(12), which was independently prepared by nitrous acid treatment of the
hydroxyimino ketone (11). The unusual formation of the sulfinyl ketones (4) and
(10) appears selective for the reaction with unhindered γ-nitro ketones and
arises on account of a neighbouring group effect from the nitro substituent.
Stereospecific synthesis of hexahydrobenzopyrroloisoquinoline and tetrahydrobenzisoquinoline derivatives
Authors: Gellert E , Kumar N
Published: September 2010

New optically active
hexahydrobenzopyrroloisoquinoline and tetrahydrobenzisoquinoline derivatives
have been synthesized. Metal hydride reduction of the cyclic amino ketones,
prepared by mild Friedel-Crafts type intramolecular acylation of N-naphthalenylmethyl amino acids,
yielded pairs of diastereoisomeric alcohols. The absolute stereochemistry and
some features of the n.m.r. spectra of hexahydrobenzopyrroloisoquinolines,
tetrahydrobenzisoquinoline and those of their intermediates are discussed.
Central nervous system active compounds. XIV. On the cyclization of N-Acyl-N'-arylureas
Authors: Heinicke G , Hung TV , Prager RH , Ward AD
Published: September 2010

The cyclization of
N-acyl-N'-arylureas in polyphosphoric
acid has been reinvestigated. The product is not only the 4-substituted
quinazolin-2(1H)-one as reported, but also contains the
2-acylaniline in major proportions. Two minor products have also been isolated.
At 80�, an intermediate has been detected, the properties of which are
consistent with it being the corresponding 2-acylphenyl- urea. Acyl ureas with strongly electron-withdrawing acyl groups form
major amounts of the corresponding anilide by the formal loss of cyanic acid.
The application of this reaction to the synthesis of quinazolinylphthalides
has been investigated.
Synthesis of analogues of GABA. XII. cis- and trans-4-Aminotetrahydrofuran-2-carboxylic acid
Authors: Allan RD , Tran HW
Published: September 2010

cis- and trans-4-Aminotetrahydrofuran-2-carboxylic acid have been
synthesized as conformationally restricted analogues
of GABA and their stereochemistry confirmed by the cyclization of the cis isomer to the bicyclic N-tosyl
lactam.
The singlet-quintet transition in Tris[2-(pyridin-2-yl)benzothiazole]iron(II) Bis(tetraphenylborate)
Authors: Baker AT , Goodwin HA
Published: September 2010

The tris[2-(pyridin-2-yl)benzothiazole]iron(II) ion has been isolated as the tetraphenylborate salt which is stable in the atmosphere
for short periods. The deep red complex displays a temperature-dependent
magnetic moment and thermochroism which are associated
with a thermally induced singlet (1A1) ↔ quintet
(5T2) spin transition. An empirical treatment of the
transition, which is continuous, yields ∆H and ∆S values of 22.7 kJ
mol-1 and 91 JK-1 mol-1 over the range 275-364
K. Spectral data for the corresponding nickel(11) complex confirm the intermediate
nature of the field strength of the benzothiazole and
indicate that it is a weaker ligand than the corresponding thiazole
derivative.
The synthesis and biological activity of (±)-(1α,2α,8α)-Indolizidine-1,2-diol
Authors: Colegate SM , Dorling PR , Huxtable CR
Published: September 2010

The racemic
indolizidine-1,2-dio1 (6) was synthesized and found to be a weak, in vitro inhibitor of acid α-D-mannosidase (Km 0.75 × 10-2) and acid
α-D-glucosidase (Km 1.1 × 10-2
M).
Studies in bile salt solutions. IV. Rile salt catalysis and inhibition of ester hydrolysis
Authors: O'Conner CJ , Wallace RG
Published: September 2010

The reactivity of
4-nitrophenyl acetate has been examined in solutions of mono-, di-, and
tri-hydroxy- cholanates and their taurine and glycine conjugates. The effect of
cholate solutions on the stability of acetylsalicylic acid, phenyl salicylate
and benzaldehyde diethyl acetal has also been determined. At the bile salt
concentrations and in the pH range of the duodenum, bile salts do not
significantly influence the stability of these compounds.
Some rearrangements of 2,3,5,6-Tetrachloro-4-methyl-4-nitrocyclohexa-2,5-dienone and 3,5-Dibromo-2,4,6-trimethyl-4-nitrocyclohexa-2,5-dienone
Authors: Gray MJ , Hartshorn MP , Vaughan J , Wright GJ
Published: September 2010

The rearrangements of the
4-nitrocyclohexa-2,5-dienones (3) and (4) in (D)chloroform and benzene are
reported, and the rearrangement mechanisms discussed. In the presence of added
phenols (18) and (20), nitromethylphenols (19) and (21) are formed in addition
to the normal rearrangement products. The mechanistic implications of this
observation are discussed.
The preparation of ethyl and isopropyl dienol ethers and dienol pivalate esters from Hagemann's ester and its t-butyl analogue, and the reactions of the derived ester dienolates with electrophiles
Authors: Baker MV , Ghitgas C , Haynes RK , Hilliker AE , Lynch GJ , Sherwood GV , Yeo H
Published: September 2010

The preparation of ethyl
4-ethoxy-2-methylcyclohexa-1,3-diene-1-carboxyate, ethyl 4-isopropoxy-
2-methylcyclohexa-1,3-diene-1-carboxylate, t-butyl
4-isopropoxy-2-methylcyclohexa-1,3-diene-1- carboxylate, ethyl 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate,
and t-butyI 4-(t-butylcarbonyloxy)-2-methylcyclohexa-1,3-diene-1-carboxylate
from Hagemann's ester and its t-butyl analogue in the presence of diethyl or diisopropyl sulfates and sodium hydride in dimethyl
sulfoxide, or pivaloyl chloride and N,N,N',N'-tetramethylethylenediamine
in tetrahydrofuran is described. The foregoing dienol ethers and esters are
smoothly deprotonated by lithium diisopropyl-
amide in tetrahydrofuran at -78" to give the corresponding ester dienolates, which react regio- specifically with a number
of electrophiles, either a or y to the alkoxycarbonyl group of the dienol ether or ester. A number
of the products, which are generally obtained in good yields, have been hydrolysed to Hagemann's ester derivatives substituted
exclusively at C1.
The four (4R)-p-menthane-1,2,8-triols
Authors: Carman RM , Fletcher MT
Published: September 2010

The four (4R)-p-menthane-1,2,8-triols have been synthesized, separated and
characterized.
Competition between reactive sites during the pulse radiolysis of styrene in aqueous solution
Authors: McAskill NA , Sangster DF
Published: September 2010

The optical absorptions of
the transient species formed by the reactions of the primary radiolysis
products of water (eaq-, ·H, and ·OH) with
styrene were measured. There are large differences between the various
literature estimates for these reaction pathways. Most of the eaq- and H and about 50% of the OH react with
the unsaturated vinyl side chain to give the α-methylbenzyl
and hydroxy-substituted methylbenzyl radical
respectively. The remaining OH reacts with the aromatic ring to give
hydroxy(vinyl)cyclohexadienyl radicals.
Five-coordination in complexes of 2-(3,5-Dimethylpyrazol-1-yl)quinoline, a sterically hindered diimine system
Authors: Baker AT , Ferguson NJ , Goodwin HA
Published: September 2010

The bidentate diimine-type ligand 2-(3,5-dimethylpyrazol-1-yl)quinoline
forms mono complexes with the bivalent chlorides of iron, cobalt, nickel and
copper. These complexes are magnetically dilute, but electronic spectral data
indicate that, except for the cobalt complex which is tetrahedral, the metal
atoms are five-coordinate and hence a chloro-bridged
structure is proposed. The cobalt(II) complex readily adds a water molecule,
and structure determination by X-ray diffraction shows that the complex aquadichloro[2-(3,5-dimethylpyrazol-1-yl)quinoline]cobalt(II)
is monomeric and five-coordinate, the coordination environment approximating
trigonal bipyramidal.
Reactions of 1-Oxaspiro[2.5]octa-5,7-dien-4-ones with nucleophiles
Authors: Cacioli P , Reiss JA
Published: September 2010

The
1-oxaspiro[2.5]octa-5,7-dien-4-ones (6-spiroepoxy-2,4-cyclohexadienones) (7) on
reaction with a number of carbon, nitrogen, oxygen and halogen nucleophiles
produced a variety of interesting substitution and rearrangement products
(8)-(19) in moderate yields. The products derived almost exclusively from
initial attack of the nucleophile with either the secondary or quaternary
carbon of the epoxy ring and these various modes of reaction of the spirocyclic
system are discussed. The formation of ortho-substituted
phenols from the 1-oxaspiro[2.5]octa-5,7-dien-4-ones suggests that the latter
structures may be regarded as polarity-reversed masked phenols. Tropolones,
products of a possible ring-expansion reaction, were not observed in any of the
reactions investigated.
An Excition Approach to the Excited States of Two Electron Atoms. I. Formalism and Interpretation
Authors: Schipper PE
Published: September 2010

The exciton model is formally applied to a description of the excited states of two
electron atoms with the explicit inclusion of exchange. The model leads to a conceptually simple framework for the discussion of the electronic properties of the archetypical atomic electron pair.
An Intramolecular Rearrangement in the Acetylation of Pyridin-4-amine
Authors: Deady LW , Finlayson WL
Published: September 2010

The surprisingly rapid formation of 4-( acetylamino )pyridine from reaction of pyridin-4-amine with various acetylating agents seems explicable by a mechanism which involves rate-determining intramolecular rearrangement of a first-formed ring N-acetyl intermediate.
Preparation of (S)-3-Azidodihydrofuran-2(3H)-one(α-Azidobutyrolactone) (1), a Useful Chiral Synthon
Authors: Davis M , Dudman NPB , White HF
Published: September 2010

(S)-3-Azidodihydrofuran-2(3H)-one (α- Azidobutyrolactone ) (1) has been resolved through the brucine salt of the corresponding hydroxy acid (2). Both (1), and various derivatives of (2), are useful synthons for the preparation of L-amino acids related to L- homoserine.
Synthesis and Analgetic Activity of cis- and trans-3-Benzyl-1-methylpiperidin-4-yl Propanoates
Authors: Bell KH , Fullick G
Published: September 2010

The diastereomeric cis- and trans-3-benzyl-1-methylpiperidin-4-yl propanoates have been synthesized as their hydrochloride salts. Both compounds are devoid of opiod agonist or antagonist activity.
(E)-1-(9-Anthryl)-2-(10-methyl-9-anthryl)ethene: Molecular Structure and Spectroscopic Properties
Authors: Becker H , Hansen L , Skelton BW , White AH
Published: September 2010

(E)-1-(9-Anthryl)-2-(10-methyl-9-anthryl) ethelle has been synthesized from 10-methyl-9-anthraldehyde and (9-anthrylmethyl) triphenylphosphonium bromide, and its crystal structure has been determined by X-ray diffraction. Its molecular geometry was found to be such as to have the planes of the two anthracene moieties form an angle of 70.8°, the plane of the ethene bond bring twisted out of the planes of the anthracenes by an angle of about 55°. The intermolecular arrangement of parallel adjacent molecules in the crystal lattice is characterized by shifts about the short and long axes of the anthracenes. The excimer-like crystal fluorescence is attributed to the interplanar distance of 3.5 Ǻ between anthracene π- systems in parallel adjacent molecules. Crystals are triclinic, Pī , a 12.95(1), b 9.316(6), c 9.098(9) Ǻ, α 86.17(7), β 72.26(7), γ 74.61(6)°,Z 2; R was 0.054 for 1059 independent 'observed' reflections.
Synthesis of Aromatic S-Sustituted Derivatives of N-Acetyl-L-cysteine
Authors: Hickman RJS , Christie BJ , Guy RW , White TJ
Published: September 2010

A new method for the preparation of aromatic, S-substituted derivatives of N-acetyl-L- cysteine is described. The method involves nucleophilic substitution of aromatic iodides by N-acetyl-L- cysteine in the presence of copper(I) iodide, and provides the first example of nucleophilic substitution of unactivated aromatic halides by N-acetyl-L- cysteine . The method has been used to prepare N-acetyl-S-(2-thienyl)-L- cysteine and N-acetyl-S-(3-thienyl)-L- cysteine from 2-iodothiophen and 3-iodothiophen respectively. In addition, the method has been successfully applied to iodobenzene and 1-iodonaphthalene. A product yield of about 30% was obtained in each case.
The Corrosion of Carbon Steel and Stainless Steel in Simulated Geothermal Media
Authors: Pound BG , Abdurrahman MH , Glucina MP , Wright GA , Sharp RM
Published: September 2010

The corrosion rates of low-carbon steel, and 304, 316 and 410/420 stainless steels in simulated geothermal media containing hydrogen sulfide have been measured by means of the polarization resistance technique. Good agreement was found between weight-loss and polarization resistance measurements of the corrosion rate for all the metals tested. Carbon steel formed a non-adherent film of mackinawite (Fe1 + xS). The lack of protection afforded to the steel by the film resulted in an approximately constant corrosion rate. The stainless steels also exhibited corrosion rates that were independent of time. However, the 410 and 420 alloys formed an adherent film consisting mainly of troilite ( FeS ) which provided only limited passivity. In contrast, the 304 and 316 alloys appeared to be essentially protected by a passive film which did not seem to involve an iron sulfide phase. However, all the stainless steels, particularly the 410 and 420 alloys, showed pitting, which indicated that some breakdown of the passive films occurred.