bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Australian soft corals. XXVIII. The structure determination of two new diterpenes from the genus Xenia (Alcyonacea)
Authors: Bowden BF , Coll JC , Ditzel E , Mitchell SJ , Robinson WT
Published: September 2010

The isolation of
'9-deacetoxyxenicin' [systematic name: (1R*,4aS*,7E,11aS*,1'R*,2'R*)-1-acetoxy-4-(1',2'-diacetoxy-4'-methylpent-3'-enyl)-7-methy1-11-methylene-1,4a,5,6,9,10,11,11a-octahydrocyclonona[c]pyran] (2) from Xenia
crassa and a further cyclized
diterpene (6) from Xenia viridis are described. The structure of (2) was derived
from n.m.r. spectroscopic comparison with xenicin (1),
whilst the structure of (6) was determined by a single-crystal X-ray analysis
when spectroscopy failed to afford an unambiguous structure.
Metal complexes of 1,10-phenanthroline derivatives. XIII. Denitrogenation in complexes of 2-hydrazino-1,10-phenanthroline
Authors: Abushamleh AS , Goodwin HA
Published: September 2010

Interaction of 2-hydrazino-1,10-phenanthroline
(L) with iron(III) or copper(II) salts results in oxidation of the ligand
through loss of nitrogen and complexation of the
oxidation product, 1,10-phenanthroline. The mixed iron(II)/iron(III) complex
[Fe(phen)3] [FeCl4]2,
identified by its magnetic and spectral properties, is formed from the reaction
with iron(III) and pure [Cu(phen)2] [BF4]2
is obtained from the reaction with copper(II) fluoroborate.
Slow denitrogenation of [FeL2] [BF4]2
has been observed in the solid state.
Unfused heterobicycles as amplifiers of phleomycin. VI. Some thienyl- and thiazolyl-pyrimidines with strongly basic side chains
Authors: Brown DJ , Cowden WB , Strekowski L
Published: September 2010

2-Chloro-4-(thien-2'-yl)pyrimidine (2a) and its thiazol-2'-yl analogue (2d) are
prepared by condensation of 2-chloropyrimidine with thien-2-yl- and
thiazol-2-yl-lithium, followed by oxidation of the dihydro
intermediates. 4-Chloro-6-methyl-2-(thien-2'-yl)pyrimidine (3b),its
2-(2',4'-dimethylthiazol-5'-yl) analogue (3f) and the
2-(2'-methylthiazol-4'-yl) analogue (4b) are made from the corresponding pyrimidinones, which are available by primary synthesis.
Each chloro compound is converted by nucleophilic displacement into its β-dimethylaminoethylamino
and β-dimethylaminoethylthio
derivatives, for which activities as amplifiers of phleomycin are reported and
discussed.
Ruthenium catalysed oxidation of cyclohexanol
Authors: Becker P , Beattie JK
Published: September 2010

The oxidation of
cyclohexanol by ferricyanide in alkaline aqueous solution is catalysed by micromolar
concentrations of K3RuCl6. The rate law at 25.0�C in pH
11.9 phosphate buffer containing 0.50 M NaCl is -d[FeIII]/dt = [Ru](2klk2[alcohol][FeIII])/(2kl[alcohol] + k2[FeIII])
with kl 12 � 2 mol-1 1. s-1 and k2 (2.5 � 0.2) × 102 mol-1
1. s-1. A deuterium isotope effect
of about 4 is observed when (D12)cyclohexanol is used. A mechanism
consistent with these observations involves reduction of the RuIII
catalyst by hydride transfer from the alcohol followed by reoxidation by
ferricyanide to the original RulIII state.
3-Alkylthio-s-triazolo[3,4-i]purines and 9-Alkylbis-s-triazolo[3,4-b:3',4'-i]purines
Authors: Brown DJ , Shinozuka K
Published: September 2010

Purin-6-ylhydrazine
(la) reacted with carbon disulfide to give s-triazolo[3,4-i]purine-3(2H)-thione
(tautomer, 2b) which underwent alkylation to yield
its S-methyl (2c) and S-carbamoylmethyl (2d)
derivatives.
In contrast, purin-8-ylhydrazine (lb) and triethyl orthoacetate gave only the intermediate N-(1'-ethoxyethylidene)-9-methylpurin-8-ylhydrazine (lc) which resisted cyclization.
Purine-2,6-diyldihydrazine (1f)
reacted with trimethyl orthoacetate,
triethyl orthoacetate and triethyl orthopropionate to give
3,7,9-trimethyl-, 9-ethyl-3,7-dimethyl- and 3,7,9-triethyl-bis-s[
3,4-b:3',4'-i]purine (4a-c),
respectively. The unexpected extra N-alkyl group was shown to occupy the 9-rather
than the 11-position by unambiguous synthesis of (4c) from 9-ethylpurine-2,6-diyldihydrazine
(1h). Structures were confirmed by n.m.r. spectra.
Comparison of σ-acyl and σ-perfluoroacyl groups as ligands: Crystal and molecular structures of the platinum(II) complexes trans-PtCl(COR)(PMePh2)2 (R = Me,CF3)
Authors: Bennett MA , Ho K , Jeffery JC , Mclaughlin GM , Robertson GB
Published: September 2010

Crystal and molecular structures of the title compounds have been determined from three dimensional
X-ray diffraction data recorded on a four-circle diffractometer. Crystals of the acetyl complex,
trans-PtCl(COMe)(PMePh2)2,(1), are monoclinic, space group P2,1/c, with a 12.9709(5), b 11.1024(5),
c 277535(9) Ǻ, β 94.75(1)° and Z 6. Crystals of the trifluoroacetyl complex, trans-PtCl(COCF3)-
(PMePh2)2, (2), are monoclinic, space group P21/n (non-standard setting of P21c), with a 11.4246(7),
b 15.5750(7), c 15.4200(8) Ǻ, β 90.54(1)° and Z 4. For (I), with Z 6, the unit cell contains one set
of four equivalent molecules in the general equipoint and one set of two equivalent (disordered)
molecules located at inversion centres. The four molecules in (2) comprise a single equivalent set
in the general equipoint. Least-squares analyses converge with R 0.042 for (1) (5696 unique data)
and R 0.025 for (2) (3933 unique data). Molecules of both complexes exhibit small deformations
from planar towards tetrahedral platinum geometry; the acyl and coordination planes are approximately
orthogonal. The phosphine substituents in (2) and in the 'general' molecules in (1) are
approximately eclipsed, and approximately eclipse the Pt-C (acetyl) bonds. In the 'special' molecules
in (1) the phosphines are constrained to adopt the mutually staggered conformation found in the
alkyl analogues trans-PtClR(PMePhM2)2 (R = Me, CF3, C2F2). Important comparative lengths
in (1) (general molecule) and in (2) (in square brackets) are: Pt-C 2.028(6) [1.960(4)] A, Pt-Cl
2.430(2) [2.390(1)] Ǻ, Pt-P 2.301(2), 2.297(2) [2.316(1), 2.321(1)] A, C-O 1.182(8) [1.210(5)] 8,
and C C (acetyl) 1.488(10) [1.547(6)] A. The trifluoroacetyl ligand forms a shorter and presumably
stronger bond with platinum, and exerts a larger cis- and a smaller trans-influence than the acyl
ligand. The smaller trans-influence of the trifluoroacetyl ligand is consistent with the expectation
from platinum-chlorine stretching frequencies (v(Pt-Cl)).
Mass spectral investigations on selenium compounds. II. The behaviour of meta-and para-substituted benzeneseleninic acids and of meta-nitrophenyl selenocyanate under electron impact
Authors: Benedetti A , Preti C , Tassi L , Tosi G
Published: September 2010

Substituted benzeneseleninic acids of the type XC6H4SeO2H
(X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO2, p-NO2) have been investigated by mass spectrometry. The
fragmentation modes and the fragment ions are discussed and compared with those
obtained from the mass spectrum of m-nitro-phenyl
selenocyanate, O2NC6H4SeCN.
Generally, as regards the acids, besides very weak peaks due to the molecular
ions, a number of peaks at higher mass numbers and of greater intensity is
observed; these peaks are in multiplets typical of
the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC6H4SeSeC6H4X.
m-Nitrophenyl
selenocyanate shows an intense molecular ion peak and
the relative fragmentation, while the peak due to the diselenide
is of very low intensity.
Plant growth regulators in Eucalyptus grandis. IV. Synthetic approaches to G-regulator analogues
Authors: Bolte ML , Crow WD , Yoshida S
Published: September 2010

A new synthetic approach is
described to the plant growth regulators of the hexahydrobenzo[e]-
1,2-dioxin group (the G-regulators of Eucalyptus
grandis). Condensation of 1,3-diketones with aldehydes under Lewis acid catalysis gives, in good yield,
the 1 : 2 adducts (4H-1,3-dioxins); these are simultaneously cleaved and (with
some exceptions) oxidized on silica gel to the desired structure. In this way
synthesis of a number of G-regulator analogues of similar physiological
activity has been achieved.
On the photochemical formation of peroxide in the system disodium Anthraquinone-2,6-disulfonate-methylviologen-water-ethanol-sodium hydroxide
Authors: Mau AWH , Sasse WHF
Published: September 2010

Reduction
of oxygen by anthraquinone radicals is shown to be
responsible for the formation of hydrogen peroxide in the title system.
Spectroscopic evidence indicates that the hydroquinone is formed by
photoreduction of the anthraquinone through sequential one-electron steps.
A convenient preparative method of jasmone and its related compounds
Authors: Watanabe S , Fujita T , Suga K , Haibara M
Published: September 2010

The reaction of
(2')-hept-4-enoic acid (1) with vinylmagnesium bromide gave
(Z)-undeca-1,8-dien- 5-one (2). The oxidation of the terminal vinylic group of
(2) affords (Z)-undec-8-ene-2,5-dione (3). Jasmone (4) was obtained by the
usual alkali cyclization of (3). A variety of alkylcyclopentenones were
prepared by the same method.
Ion-ion-solvent interactions in solution. Aqueous solutions of nitrates of cations from Groups 2A and 3A
Authors: James DW , Frost RL
Published: September 2010

Association
equilibria in aqueous solutions of the salts Be(NO3)2,
Ca(NO3)2 Sr(NO3)2,
Ba(NO3)2 and Al(NO3)3
have been studied through band shape and component band analysis of the non-degenerate,
Raman-active V1 vibrational
band of the nitrate ion. Band contributions due to the
aquated
nitrate ion, solvent-separated ion pair, and contact ion pair were made for all
salts. The nature of the contact ion pair was shown to be different in the
presence of Be2+ and Al3+ from that seen for the other
salts. This difference was associated with a strongly directional perturbation of
the nitrate ion. For all salts the solvent-separated ion pair species was
present in the lowest concentration solution studied (as low as 0.05 M). At
intermediate concentrations the solvent separated ion pair species was the
dominant solution species while at the higher concentrations the species with
anion and cation in contact becomes appreciable. For
solutions of Ca(NO3)2 some evidence for a more extensive
ion aggregate was found at the highest concentration (5M).
Equilibrium
quotients calculated from the spectroscopic components are in reasonable
agreement with previous values determined by equilibrium and transport
measurements, and it is suggested that these previous determinations detected
the presence of solvent-separated ion pairs rather than contact ion pairs.
The hydrogen bromide catalysed decomposition of 3-methylbutan-2-ol
Authors: Johnson RL , Stimson VR
Published: September 2010

In the presence of hydrogen
bromide at 372-446�C 3-methylbutan-2-ol decomposes into methylbutenes
and water with rate
K2=1013.02exp(-150000/8.314T) ml mol-1s-1
The effects of substitution
at the β-carbon atom (C3) are summarized and compared with those at the α-carbon
atom (C2). A polar transition state involving mainly the α-carbon atom
site is proposed.
Dehydration studies of α- and β-ionol. II. With Toluene-p-sulfonic acid
Authors: Whitfield FB , Sugowdz G , Hlubucek JR
Published: September 2010

α-Ionol
(2), when made to react with a 5% solution of toluene-p-sulfonic acid at 20� for 120 h, gave in
20% yield one major dehydration product (1'E)-6-(buta-1',3'-dienyl)-1
,5,5-trimethylcyclohex- 1-ene (4a) together with trace quantities of the (1'Z)-isomer
(4b). β-Ionol (3) under similar conditions gave
after 10 min in 84% yield (6E,2'E)- and (6Z,2'E)-6-(but-2'-enylidene)-1,5,5-trimethylcyclohex-1-ene
(la) and (1b). Minor products from this reaction included the isomeric trienes (1c) and (1d). However, at 80� the alcohols (2) and
(3) gave in about 60% yields complex mixtures of dehydration products which
included 1-butyl-2,3,6-trimethylbenzene (7), 1-butyl-2,4,6-trimethylbenzene
(8), 1,1,6-trimethyl-1,2,3,4-tetrahydronaphthalene (9) and 1,1,4,4-tetramethyl-2,3,4,5,6,7-hexahydro-
1H-indene (10). Minor products
obtained at 80�included 1,1,4,4-tetramethyl-,4,5,6 tetrahydro-
1H-indene (11) and 1,4,4,7a-tetramethyl-5,6,7,7a-tetrahydro-4H-indene (12). The
trienes (la-d) and (4a,b) when treated with toluene-p-sulfonic
acid at 80� also yielded the compounds (7), (8), (9) and (10). Reaction
pathways are suggested for the formation of all identified compounds.
The anomalous reaction of p-Methoxy-β,β-dimethylstyrene with mercury(II) acetate in methanol
Authors: Norris RK , Wright TA
Published: September 2010

The methoxymercurations of β,
β-dimethylstyrene (7) and its p-nitro
(12) and p-methoxy (13) derivatives
with mercury(II) acetate in methanol are regiospecific and give
methoxymercuration products in which the methoxy group is on the β-carbon.
Demercuration of the adducts from (12) and (13) with alkaline borohydride
proceeds normally, but the demercuration of the adduct from (7) gives
considerable formation of the diastereoisomeric dimeric products (9a,b). The
methoxymercuration product from (13) is surprisingly reactive and gives mercury
or mercury(1) acetate and the vicinal diether 1,2-dimethoxy-1-(p-methoxyphenyl)-2-methylpropane
(17).
Crystal structure of tetraphenyltin(IV) (a redetermination)
Authors: Engelhardt LM , Leung W , Raston CL , White AH
Published: September 2010

The
crystal structure of tetraphenyltin(IV) has been redetermined at 295(1) K, full-matrix least-squares refinement
yielding a residual of 0.031 for 557 independent 'observed' reflections. The
tin-phenyl carbon distance is 2.143(5) �, with the angles subtended
at the tin atom being 108.9(2) and 110.5(2)�.
Intramolecular hydrogen bonding in some ortho-substituted N-methyl,N-benzyl and N-aryl-4-nitroanilines: a proton magnetic resonance study
Authors: Wilshire JFK
Published: September 2010

1H n.m.r. spectra of a wide variety of N-methyl, N-benzyl and N-aryl
2-substituted 4-nitroanilines, where the 2-substituent is an
electron-withdrawing group, namely acetyl, cyano, formyl or methoxy-carbonyl, reveal that long-range coupling
(5J 0.65-0.70 Hz) occurs between the NH proton and the 5-proton of
the nitroaryl ring in (D)chloroform solution; coupling
is absent when the 2-substituent is trifluoromethyl.
However, for some compounds (the nature of the 2-substituent is critical), NH,H5
coupling is absent in (D6)dimethyl sulfoxide solution. An
examination of these phenomena leads to the conclusion (a) that intramolecular hydrogen bonding occurs between the NH
group and the 2-substituent and (b)
that, for these N,2-substituted
4-nitroanilines, the intramolecular hydrogen bond strength decreases in the
following order:
NH...COOCH3>NH...NO2≈NH...COCH3>NH...CHO>NH...CN
A parallel study involving
some N-methyl 4-substituted
2-nitroanilines where the 4-substituent is an electron-donating group, namely
t-butyl, methyl and methoxy, revealed long-range NH,H5 coupling in
both (D)chloroform and (D6)dimethyl sulfoxide solution; when the
substituent is dimethylamino, NH,H5
coupling could not be detected in either solvent.
Crystal structure of Bis[N,N-diethyl(dithiocarbamato-S,S')][N,N-diethyl-(dithioperoxycarbamato-O,S)]chromium(III). (A redetermination)
Authors: Martin RL , Patrick JM , Skelton BW , Taylor D , White AH
Published: September 2010

The crystal structure of
the title compound, [Cr(S2CNEt2)2(OS2CNEt2)]
has been determined by single crystal X-ray diffraction methods, being refined
to a residual of 0.061 for 2756 'observed' reflections. Crystals are
monoclinic, P21/c, a
16.195(5), b 8.316(2), c 17.939(7) �, ,β 96.65(3)�, Z 4.
The chromium atom is coordinated by two S,S-chelate
ligands and one O,S-chelate ligand, the latter being disordered over three
sites.
The reactions of some compounds of manganese with molten lithium carbonate-sodium carbonate-potassium carbonate eutectic
Authors: Salarzadeh I , Tariq SA
Published: September 2010

The reactions of MnO, MnCl2, MnCO3, MnSO4,
Mn2O3, Mn3O4, MnO2 and KMnO4 with
molten lithium carbonate-sodium carbonate-potassium carbonate eutectic were
studied under argon as well as carbon dioxide atmospheres. Final products for
MnCl2 reaction consisted of a mixture of oxy anions, MnO2-
and MnO32-, and those for MnCO3 were MnO32-
and Mn2O52- as were for the reactions of MnSO4
and MnO2. Mn2O3 and Mn3O4
reacted to form the oxy anion, MnO2-. KMnO4 decomposed to
form initially a mixture of Mn7O164- and MnO42-.
These oxy anions reacted further with the eutectic to produce the oxy anion, MnOS32-.
Three alkali metals were present as cationic species with the above manganese
oxy anions in different ratios. The carbonate melt acted both as a reaction
medium and as a Lux-Flood base, that is a donor of
oxide ions evolving carbon dioxide which was partly reduced to carbon monoxide
in the reactions involving manganese(II) compounds. The stoichiometries
of these reactions have been suggested. Manganese(II) oxide was found to be unreactive with the carbonate eutectic.
Halogenated pyrrolo[2,3-d]pyrimidine nucleosides from marine organisms
Authors: Kazlauskas R , Murphy PT , Wells RJBJA , Jamieson DD
Published: September 2010

4-Amino-5-bromopyrrolo[2,3-d]pyrimidine has been isolated from a sponge (Echinodictyum
sp.). The pharmacologically active constituent of the red alga Hypnea valendiae has
been identified as 4-amino-7-(5'-deoxyribos-1'β-yl)-5-iodopyrrolo[2,3-d]pyrimidine (7). A second nucleoside, tentatively assigned
as the 1'α isomer of (7), has also been isolated.
A further extension of the linear relationship between molecular rotation and bond refraction in open-chain monosubstituted alkanes
Authors: Poh B
Published: September 2010

It has been shown that, in the
correlations of molecular rotations with bond refractions for open-chain mono-substituted
alkanes, H(CH2)b(CH3)C*H(CH2)nX (b > 1, n ≥ 0), the compounds with different n and X for a given b can
now be grouped into a single series.
Mutarotation of D(+)-glucose. II. Volumes of activation for the uncatalysed and copper(II)-catalysed rates
Authors: O'Conner CJ , Odell AL , Bailey AAT
Published: September 2010

The effect of high pressure
on the rate of mutarotation of α-and β-D(+)-glucose
in aqueous sodium perchlorate solutions has been
evaluated. The observed rate constant kΨ =
kα + kβ
increases with pressure while the equilibrium constant Keq
= kα /kβ
is nearly unchanged from the 1.7 found at 1 bar. From the experimental results,
the individual rate constants kα
and kβ and the corresponding
activation volumes ∆V‡α and ∆V‡β can be evaluated. The values obtained,
-10.7 � 0.1 and -10.0 � 0.1 cm3 mol-1, are discussed in
relation to the reaction mechanism. In the presence of Cu(ClO4)2
the values of ∆V: form a continuous series, dependent upon the pH and the
concentration of copper(II) catalyst, up to + 1.3 cm3 mol-1. The activation
volumes for mutarotation by monomeric and dimeric
copper(II) catalysts, ∆V‡(Cu2+) and ∆V‡ {CU((OH)2Cu)2+},
are -1.2 � 0.2 and + 3.6 � 0.2 cm3 mol-1 respectively.
Reaction mechanisms are discussed to account for these values of ∆V‡.
Structure and redox properties of the molybdenum(IV) metal cluster K5[Mo3S4(CN)9].7H2O
Authors: Howlader NC , Haight Jr GP , Hambley TW , Lawrance GA , Rahmoeller KM , Snow MR
Published: September 2010

The anionic molybdenum(IV)
cluster [Mo3S4(CN)9]5- has been
subjected to X-ray crystal structure analysis. The potassium salt crystallized
in the triclinic space group P1, a
10.634(1), b 11.888(3), c 24.892(2) �, α 89.56(2), β
79.86(1), γ 76.53(2)�, Z 4. The three MoIV atoms in each unit
of approximately CSL3v symmetry are situated at the corners of an
equilateral triangle with Mo-Mo distance 2.765(7) �. There are three S2-
ligands bridging between pairs of Mo atoms, and a unique S2- ligand
located uniformly above the plane of the equilateral triangle. Distorted
octahedral coordination of each MoIV is
completed by three CN- ligands to each of the three metal centres.
The ion is structurally similar to the [MO3S(S2)6]2-
precursor, and to [Mo3O4X9]n-
analogues. In dimethyl sulfoxide, the cluster is irreversibly reduced in a
single step near -2 V (v. saturated calomel electrode), but exhibits a
quasi-reversible oxidation at + 0.51 V. On the coulometric
time scale, the complex is irreversibly oxidized to MoV
monomer.
The stereochemistry of alkali metal/ammonia reductions of stilbenes: Application in the synthesis of 14C-labelled meso-hexoestrol
Authors: Collins DJ , Hobbs JJ
Published: September 2010

Some α,α-disubstituted
stilbenes were reduced with lithium, sodium or
potassium in anhydrous liquid ammonia by two procedures: (A) the alkali metal
was added to a solution of the stilbene in
ammonia/tetrahydrofuran; and (B) a solution of the stilbene
in tetrahydrofuran was added to a preformed blue solution of the alkali metal
in ammonia. For the more sterically crowded stilbenes the ratio of bibenzyl diastereoisomers formed
differed according to the alkali metal and the reduction procedure used. The
results were exploited in a synthesis of 2-14C-labelled meso-hexoestrol.
Kinetics of site-exchange reactions in di- and tri-methylplatinum(IV) glycinate complexes, from N.M.R. lineshape analysis
Authors: Appleton TG , Hall JR , Ham NS , Hess FW , Williams MA
Published: September 2010

Site-exchange reactions for
PtMe3(gly)(D2O), and isomers of
PtMe2Br(gly)(D2O) with D2O
coordinated trans to methyl have been
studied, and rate constants determined by complete line shape analysis of 1H
n.m.r. spectra in the methyl region (gly = H2NCH2CO2-).
It is proposed that these reactions involve exchange of the labile water
molecule with solvent water, with an associated migration of a donor atom
(nitrogen or oxygen). Dissociative and associative (edge displacement) reaction
pathways compete. The site-exchange reaction for PtMe3(gly)2- appears to occur by dissociation of a Pt-O
bond.
Resonance and solvent effects on absorption spectra of some 2- and 4-( - M)-substituted aniline derivatives
Authors: Yokoyama T , Taft RW , Kamlet MJ
Published: September 2010

The N-H protons of N-methyl-2-X-aniline derivatives remain intramolecularly hydrogen bonded in HBA (hydrogen bond
acceptor) solvents where X = COOMe and NO2,
but form intermolecular hydrogen bonds to the HBA solvents where X = CN. The
order of response of vmax to solvent HBA basicity for the Cl → C2 bands of N-unsubstituted-2-(-M)-substituted
aniline derivatives and the Cl → C4 bands of 4-(-M)-substituted aniline
derivatives follows the orders of the hydrogen bond donor acidities of the
amine protons, which are determined primarily by the mesomeric
effects of the 2- and 4-substituents. The spectral data indicate that intramolecularly hydrogen bonded 2-(-M)-substituted aniline
derivatives are near sp2 hybridized in non-HBA solvents and, unlike
several 4-substitute anilines, do not undergo significant rehybridization
in HBA solvents. Bath ochromic shifts resulting from
hydrogen bonds by corresponding 2- and 4-substituted aniline derivatives to HBA
solvents are of similar magnitudes.
A proton N.M.R. study of the conformation of Trp-Gly-Ala-Glu in dimethyl sulfoxide and water
Authors: Beilharz GB , Fong J , Mack POL , Robertson AV , Wright PE
Published: September 2010

Proton nuclear magnetic
resonance parameters are reported for Trp-Gly-Ala-Glu, constituting residues 115-118 of bovine myelin basic protein, in dimethyl sulfoxide solution. The
3JNH,α vicinal coupling constants which were used to determine Φ torsional angles,
together with the amide proton temperature coefficients, are consistent with a
type I ,βturn conformation. Amide proton tempera- ture coefficients
obtained for the peptide dissolved in H2O at pH 1.3, 4.6 and 6.5 indicate that
the peptide does not adopt any highly preferred folded conformation in water.
These findings lend support to previous reports of a reverse turn involving the
Trp-Gly-Ala-Glu portion of the encephalitogenic nonapeptide
Phe-Ser-Trp-Gly-Ala-Glu-Gly-Gln-Lys from bovine myelin basic protein.
Reduction of N-substituted azetidin-2-ones to azetidines
Authors: Jackson MB , Mander LN , Spotswood TM
Published: September 2010

Reduction of N-substituted
azetidin-2-ones to N-substituted azetidines was accomplished rapidlyand in good yield with
diborane in tetrahydrofuran and with alane in ether. The stereochemistryof the ring substituents
was retained under the reaction conditions. 3-Aminopropanol derivativesformed by reductive ring
cleavage were sometimes obtained as by-products in diborane reductionsbut not in alane
reductions. The reductions of fourteen azetidin-2-ones to azetidines with
diboraneand eighteen with alane are
reported.
Dimorphism of zinc(II) dithizonate
Authors: Harrowfield JM , Pakawatchai C , White AH
Published: September 2010

Zinc dithizonate, Zn(HDZ)2,
HDz = C13H11N4S-, has been found to occur in two crystalline modifications, the
structure of one form ('α') having already been determined; its redetermination
is reported here, together with that of the 'β' form. Crystals of the 'α' form
are monoclinic, P21/c, a 7.887(3), b 22.40(1), c 15.324(6) Ǻ, β 92.82(3)°, Z 4;
the structure has been refined by least squares to a residual of 0.061 for 2061
'observed' diffractometer reflections. The cell dimensions of the 'β' form are
remarkably similar, but with an interchange of axes; crystals are monoclinic,
P21/c, a 7.607(2), b 15.66(1), c 2276(1) Ǻ, β 94.97(3)°, Z 4, the structure
being refined to a residual of 0.039 for 1846 'observed' reflections. The zinc
environments in both structures are very similar, the zinc atoms being
four-coordinate with a pair of similar N,S-chelating ligands about each. For
the α form, Zn-S are 2.272(3), 2.271(3) A, S-Zn-S, 130.6(1)° Zn-N are
2.058(7), 2.083(6) °, N-Zn-N, 107.7(3)°, while the chelate N-Zn-S angles
are 86.6(2), 86.8(2)°, and interligand N-Zn-S, 120.6(2), 126.0(2)°.
For the ° form, Zn-S are 2.256(2), 2.270(2) A, S-Zn-S, 129.4(1)°; Zn-N are
2.064(5), 2.053(5) A, N-Zn-N, 107.4(2)°, while chelate N-Zn-S angles are
86.2(1), 86.5(1)°, and interligand N-Zn-S, 125.0(2), 124 4(1)°.
Preparation, and complexes with nickel(II) and copper(II), of a diazepane amine alcohol. The structure of [4,4-dimethyl-7-(5,5,7-trimethyl-1,4-diazepan-1-yl)-5-azaheptan-2-ol]nickel(II) perchlorate
Authors: Morgan KR , Gainsford GJ , Curtis NF
Published: September 2010

Reduction of
4,4,12,12-tetramethyl-5,8,11-triazapentadecane-2,14-dione diperchlorate by
sodium borohydride yields as the major product one
isomer of 4,4-dimethyl-7-(5,5,7-trimethyl-1,2-diazepam 1-yl)-5-azaheptan-2-ol, pyaz. The coordination compounds [M(pyaz)]
(ClO4), and [Ni(pyaz)(NCS)] CNS (M = NiII,
CuII) were prepared, the latter being assigned five-coordinate
structures. The structure of singlet ground state [Ni(pyaz)]
(ClO4)2 was determined by X-ray diffraction [space group
P212121, Z 4, a 1450.8(2), b 1522.2(1),
c 1048.5(1) pm, R 0.0675, Rw 0.0768 for 2461 reflections]. The compound
has a square-planar coordination arrangement, with the three nitrogen and the
oxygen donor atoms of the pyaz ligand approximately
coplanar [Ni-O 190.0(6) pm; Ni-N 192.8(6), 189.2(6), 189.2(6) pm in sequence
N(5) of chain, N(l), N(4) of diazepane]. The diazepane ring adopts a boat conformation. One side of the
nickel(II) coordination plane is sterically crowded
by the presence of two axial methyl substituents. The ligand has two
non-equivalent chiral centres (C(14) of the diazepane ring and C(2) of the amine alcohol chain), both
present in the R configuration in the crystal studied. The three nitrogen
atoms, which became chiral centres upon coordination,
are present in the S configuration for two diazepane
nitrogen atoms and in the R configuration for the 5-aza chain nitrogen.
Solvation of ions. XXXI. Partial molal volumes of sodium, silver(I) and copper(I) ions in acetonitrile/water mixtures
Authors: Singh P , MacLeod ID , Parker AJ
Published: September 2010

The partial molal volumes of Na+, Ag+, Cu+,
Ph4As+, BPh4-, Cl- and
NO3- are reported for transfer from water to various acetonitrile/water (MeCN/H2O) mixtures by using
the tatb assumption that ΔVt(Ph4As+)
= ΔVt(BPh4-). The results,
which show a complex dependence of ionic partial molal
volumes on MeCN/H2O solvent composition, are discussed in terms of
ion-solvent and solvent-solvent interactions. This study complements earlier
work on the energetics of transfer (tatb assumption)
of these ions from water to aqueous acetonitrile
solutions.
Lewis-base adducts of Group 1 metal(I) compounds. III. Synthesis and crystal structures of the 1 : 1 adducts of silver(I) iodide with triethylamine, 2- and 3-methylpyridine and quinoline
Authors: Healy PC , Mills NK , White AH
Published: September 2010

The crystal structures of
the title compounds have been determined at 295(1) K by single-crystal X-ray
diffraction methods. For [AgI(Et3N)] (1),
the unit cell is tetragonal, P42/nmc,
a 13.202(6),c 11.654(8) �; the structure was refined to a residual of 0.077 for
589 independent 'observed' reflections, and is isostructural
with the 'pseudo-cubane' triethylphosphine
and triethylarsineanalogues with two tetrameric units in the cell. For [AgI(2-MeC5H4N)]
(2), the cell is orthorhombic,P212121, a 16.63(1), b 10.797(9), c 4.570(4) �,
Z 4; a residual of 0.030 was obtained for 770 independent 'observed'
reflections. For [AgI(3-MeC5H4N)]
(3), the cell is monoclinic, P21/n,
a 19.57(2), b 4.633(3), c 9.355(7) �,
β 90.85(7)�, Z 4, a residual of 0.038 being obtained for 1382 independent
'observed' reflections. For [AgI(C9H7N)](4),
the unit cell is monoclinic, P21/n,
a 12.964(9), b 16.84(2), c 4.454(4) �,
β 97.10(7)�, Z 4, a residual of 0.040 being obtained for 660 'observed'
independent reflections. For compounds (2)-(4), the observed structures are all
'stairpolymers'; the structures of (2) and (3) are
quite similar, but that of (4) exhibits significant differences.
22b-[(S)-2-Methylbutanoyloxy]-3-oxoolean-12-en-28-oic acid, a new constituent of Lantana camara
Authors: Johns SR , Lamberton JA , Morton TC , Suares H , Willing RI
Published: September 2010

22β-[(S)-2-Methylbutanoyloxy]-3-oxoolean-12-en-28-oic
acid, a new constituent of Lantanu camara L. is closely related to lantadene
A and lantadene B. Although hydrolysis gives
2-methylbutanoic acid as a partial racemate, it has
been shown by n.m.r. spectroscopy that the natural ester is theoptically
pure (S)-isomer. Catalytic hydrogenation of lantadene
A gives a mixture of diastereoisomeric esters in which the
(S)-2-methylbutanoate predominates, and a 1 : 1 mixture of the (R)-
and(S)-esters was obtained by esterification with
(RS)-2-methylbutanoyl chloride of 22β-hydroxy-3-oxoolean-12-en-28-oic acid
protected as the diphenylmethyl ester.
Transference numbers and conductance in concentrated copper(II) chloride solutions at 25°C
Authors: Ellis RN , Stokes RH , Wright AC , Spiro M
Published: September 2010

Transference numbers in concentrated copper(II) chloride solutions at 25°C are obtained by (i) a
modified moving boundary method using other solutions to isolate both electrodes from the
CuCl2 solution, and (ii) the e.m.f. method using cells with transference with gaseous chlorine
electrodes. Conductance and density measurements are also reported. The transference results
support the more recent Russian work against the earlier measurements of Denham; there is no
evidence of negative cation constituent transference numbers, and it is concluded that anionic chloro
complexes are not a major constituent of the concentrated solutions. In this respect copper(II)
chloride differs from the halides of cadmium and zinc.
Thermodynamic and kinetic studies of silver ion complexes with cyclic and open chain diaza-polyethers including cryptands in acetonitrile + water mixtures
Authors: Cox BG , Stroka J , Firman P , Schneider I , Schneider H
Published: September 2010

.The stability constants for Ag+ complexes of several diazapolyether ligands, L = (2,2,1), (2,1),
(2,2) and (2) (Scheme 1), have been measured in acetonitrile and water mixtures. Rate constants
for formation and dissociation of Ag(2,2,1)+, together with the free energies of transfer, ΔGtr,
of (2,2,1) among the mixtures, are also reported, and are compared with corresponding values
for the Ag+-(2,1,1) and Ag+-(2,2,2) systems. The solvent dependences of the stability constants and
hence of ΔGtr(AgLCIO4) - AG,,(L) are almost identical for all systems, except for small differences
at low water content between the behaviour of the bicyclic cryptand ligands [(2,2,2), (2,2,1), (2,1,1)]
and the monocyclic and acylic ligands, attributable to effects of NH solvation in the latter group.
The preferential solvation of Ag+ by acetonitrile in the mixtures results in a sharp decrease in the
stability constants as acetonitrile is added to water, but the effect is partly compensated for by a
corresponding decrease in the free energies of the complexes. A strong differentiation in the kinetic
behaviour of the bicyclic cryptand ligands is observed. For (2,1,1) the formation rates are almost
independent of solvent composition and the free energies of transfer of the activated complex,
ΔG‡tr (Ag+. . .(2,1,1),ClO4-) closely parallels that of AgCIO4, whereas for the larger cryptands the
formation rates show a stronger solvent dependence, and ΔG‡tr (Ag+. . .L,ClO4-) values much more
closely resemble those of the stable complexes, ΔG‡tr (AgLClO4). It is suggested that for the smaller
(2,1,1) ligand preferential solvation of Ag+ by acetonitrile still persists in the transition state, but
that in the activated complex for (2,2,1) and (2,2,2) the strong interactions between Ag+ and the
ligand nitrogens have already replaced the Ag+. . .N≡CCH3 interactions occurring for the
uncomplexed Ag+ ion in the mixtures.
Conformational analysis of picrotoxinin by N.M.R., X-ray crystallography, and molecular orbital and classical potential-energy calculations
Authors: Andrews PR , Brownlee RTC , Mackay MF , Poulton DB , Sadek M , Winkler DA
Published: September 2010

The conformation of the
potent convulsant drug picrotoxinin has been studied by proton n.m.r., X-ray
crystallography, molecular orbital calculations and classical calculations. The
calculations reveal two alternative low-energy conformations, either of which
is consistent with the n.m.r. data, and one of which is also observed
crystallographically. The energy difference is sufficiently small to suggest
that either conformation may be the biologically active form.
Inhibitors of the geotropic response in plants. The crystal structures of 2-[(Naphthalen-2-yl)carbamoyl]benzoic acid (β-Naptalam), 2-(Phenylcarbamoyl)-benzoic acid and 2-(5-Phenyl-1,3,4-oxadiazol-2-yl)benzoic acid
Authors: Smith G , Kennard CHL , Katekar GF
Published: September 2010

The crystal structures of
three geotropically active phthalamic acid
derivatives have been determined by means of X-ray diffraction and the
structural systematics for the series compared. The
three acids are conformationally similar and, in
contrast to the tendency among carboxylic acids to form hydrogen-bonded dimers,
they exist as monomers with intermolecular hydrogen bonding between the
carboxylic acid groups and the nitrogen or oxygen of the amide side chains.
Reactions with thioethoxide ion in N,N-dimethylformamide. III. Regioselective demethylation of 4-(2',7'-Dimethoxy-1'-naphthyl)-2-methylbutan-2-ol
Authors: Cannon JR , Feutrill GI , Wong LCH
Published: September 2010

Reaction of
2,7-dimethoxy-1-methylnaphthalene with sodium thioethoxide in N,N-dimethylformamide leads to a mixture
of approximately equal parts of the isomeric O-monomethyl ethers of 1-methylnaphthalene-2,7-diol, but under the
same conditions 4-(2',7'-dimethoxy-1'-naphthyl)-2-methylbutan-2-ol undergoes
regioselective demethylation of the more hindered 2'-methoxyl group.
Anionopentaaminecobalt(III) complexes with polyamine ligands. XIX. Computer simulated intermediates for dissociative aquation reactions
Authors: House DA , Maclagan RGAR
Published: September 2010

Strain energy minimization
calculations have been performed for several octahedral chloropenta-amine
cobalt(III) complexes with polyamine ligands. Similar calculations on the
five-coordinate residue obtained by removal of the chloro
ligand allow an estimation of the geometry and energy of a potential
intermediate in a chloride release reaction proceeding via a dissociative
mechanism. In all cases the five-coordinate residue is less strained than the
six-coordinate octahedron and the non-replaced ligands play an essential role
in determining the resulting distortion. Thus for the series mer-CoCl(NN)(dien)2+ (NN = en, (NH3)2,tn),
the total strain energy difference between the minimized ground state and the
minimized five-coordinate residue is 12.2, 18.3 and 25.8 kJ mol-1,
respectively. This order is identical (where data are available) to that of the
rate constants (and activation energies) for thermal aquation,
Hg2+ assisted aquation and mer → fac-dien isomerization in this series.
Similar calculations have been performed for a series of trans-CoCl2(N4)+
systems and again the energy differences are in the approximate order of the
rates of thermal aquation. In the case of N4
= (NH3)2, the energy difference between trans-and cis-CoCl(NH3)4(OH2)2+
products is about 1 kJ mol-1, the trans-isomer being the more stable.
The structure of u-fac-(Diethylenetriamine)[di(3-aminopropyl)amine]cobalt(III) perchlorate, [Co(dien)(dpt)] (ClO4)3, and an energy minimization analysis of the [Co(dien)(dpt)]3+ system
Authors: Hambley TW , Searle GH
Published: September 2010

X-ray crystallographic
analysis of u-fac-[Co(dien)(dpt)] (ClO4)3,H2O
[dien = diethylenetriamine,
dpt = di(3-aminopropyl)amine] confirms the assigned u-fac
geometry. The two six-membered chelate rings of the coordinated dpt adopt chair and flattened-chair conformations. The
crystals are triclinic, space group P1, with a 8.979(2), b 11.436(2), c 11.463(3) �, α 91.15(2), β
101 .84(2), γ 93.41(2)�. A molecular mechanics analysis of the three [Co(dien)(dpt)]3+ geometric
isomers gives the u-fac as the most
stable, in accord with experimental observations.
Reactions of biogenic amines with quinones
Authors: Tindale CR
Published: September 2010

Reactions of
benzo-1,4-quinone with 2-phenylethylamine and p-tyramine produced the novel 2,5- diamino-derivatives (2b,c), analogous to
2,5-dianilinobenzo-1,4-quinone (2a). 2,5-Dihydroxybenzo- 1,4-quinone (3) reacts
with aniline to form the tetrol (4a) and not
2,5-dianilinobenzo-1,4-quinone (2a) as previously reported. This tetrol (4a) may hydrolyse to form
the monoimine (5a). Only in boiling aniline was the
2,5-dianilino derivative (2a) produced from the tetrol
(4a). Novel tetrols were similarly isolated from
2-phenylethylamine, p-tyramine and histamine. Benzo-1,2-quinone reactions with
aniline and the above amines were also studied. Implications of these reactions
for the extraction of amines from foods are discussed.
The stereochemistry of Bis(α,α'-diimine)copper(I) complexes: the crystal and molecular structures of Bis(2,9-dimethyl-1,10-phenanthroline)copper(I) bromide hydrate, Bis(4,4',6,6'-tetramethyl-2,2'-bipyridine)copper(I) chloride dihydrate, and Bis(2,9-dimethyl-1,10-phenanthroline)copper(I) nitrate dihydrate (a redetermination)
Authors: Dobson JF , Green BE , Healy PC , Kennard CHL , Pakawatchai C , White AH
Published: September 2010

The crystal structures of
the title compounds have been determined by single-crystal X-ray diffraction
methods at 295 K, and refined by least-squares methods. Crystal data for [Cu(Cl4H12N2)2]
Br.H2O (1) are: monoclinic, P21/c, a 14.067(4), b 17.687(6), c 10.337(5) �, β 91.04(3)�, with R
0.038, R' 0.040 for 1855 'observed' reflections. Crystal data for [Cu(Cu14H12N2)2]
C1.2H2O (2) are: triclinic, P1, a
15.305(2), b 13.164(2), c 7.344(3) �, α 83.03(3), β
93.83(3), γ 108. 11260(3)�, with R 0.051, R' 0.053 for 1293 'observed'
reflections. Crystal data for [Cu(Cl4H12N2)2]
Br.H2O (3) are: triclinic, P1, a
7.619(2), b 11.967(3), c 15.534(3) �, α 71.26(1), β 82.13(1),
γ 86.86(2)�, with R 0.043, R' 0.052 for 2335 'observed' reflections. The
anionic and solvent species are uncoordinated in all three compounds. Cu-N bond
lengths range from 2.027(5) to 2.053(5) �. The copper(1) environment (CuN4)
in each complex shows considerable distortion from tetrahedral geometry. N-Cu-N
intraligand angles range from 81.0(2) to 83.0(2)�,
while N-Cu-N interligand angles range from 114.7(2)
to 135.2(2)�. The variation in interligand angles can
be described in terms of three independent rotations of ligand 2 about an
orthogonal axial system defined by ligand 1.
The relationship of εL and εR from consideration of bisignate C.D. curves of α,β-unsaturated ketones
Authors: Beecham AF , Fock W , Mathieson AM
Published: September 2010

From reconsideration of experimental
evidence of ∆ε and ε curves and extrapolation of comments by
Beecham and Collins1 it is concluded that the occurrence of bisignate n- π* c.d. curves for ketones and α,β-unsaturated
ketones does not require hypothesizing the existence of two spectral bands of
opposite sign and therefore indicates that the relationship between εL and εR for a single transition does not necessarily involve a simple
constant amplitude factor as the conventional interpretation holds. An alternative
interpretation of bisignate curves is proposed, based
on one spectral band, the relationship between εL and εR involving
differential half-widths of the vibronic components
of the L series relative to the R series and a variable relative-amplitude scale
along the vibronic progression. If appropriate scale
and differential half-width parameters are used, the characteristics of monosignate and bisignate curves
can be demonstrated by means of synthetic curves.
A fallacy in some interpretations of the quasi-thermodynamics of reaction kinetics
Authors: Hamann SD
Published: September 2010

The fact that
experimentally determined 'volumes of activation' and 'entropies of activation'
obey a relationship that is formally similar to one of Maxwell's thermodynamic
relations is a mathematicalconsequence of the
definitions of those quantities. Contrary to suggestions in the literature, it
provides no evidence in support of the quasi-thermodynamic and equilibrium
assumptions of the transition state theory.
Variable deprotonation of an aromatic amino ligand by molybdenum(VI). Crystal and molecular structure of mer-Bis[2,2'-{1,2-phenylenebis(iminomethylene)}-bis(phenol)ato(3 - )]molybdenum(VI)
Authors: Gheller SF , Hambley TW , Snow MR , Murray KS , Wedd AG
Published: September 2010

The ligand
2,2'-[1,2-phenylenebis(iminomethylene)]bisphenol, H4L, features two phenolic and two
aromatic secondary amino functions. Reaction of H4L with [MoO2(acac)2] in MeOH leads
to cis-[MoO2(H2L)]
in which the two phenolic protons are displaced and H2L2-
acts as a quadridentate ligand. Reaction of H4L
with (pyH) [MoOBr4and NaOMe
in MeOH precipitates a brown solid. Extraction with
fresh MeOH provides low yields of mer-[Mo(HL)2].MeOH which was characterized structurally by X-ray
crystallography. The compound features the tridentate ligand HL3-
where two deprotonated amino nitrogens
and one deprotonated phenolic oxygen are ligand atoms
and the other phenolic oxygen is protonated and not
bound to the metal. The steric requirements of the ligands impose a distorted
octahedral stereochemistry which also permits effective metal-ligand multiple
bonding revealed by short metal-ligand bond lengths. Crystal data: a 9.963(5); b 17.244(4); c 20.703(8)�;
β 93.32(4)�; P21/c; Z 4.
Organophosphorus compounds. XX. Approaches to the synthesis of 2,3-Dihydro-1H-1,2-benzazaphospholes involving C-C and C-P ring closure
Authors: Collins DJ , Drygala PF , Swan JM
Published: September 2010

Reaction of chloromethylphosphonic dichloride (9) with N-methylaniline gave N,N'-dimethyl-N,N'-diphenylchloromethylphosphonodiarnide
(10) which upon treatment with aluminium chloride underwent intramolecular
Friedel-Crafts alkylation to afford 1-methyl-2-(N'-methyl-N'-phenylamino)-2,3-dihydro-1N-l,2-benzazaphosphole 2-oxide(13a). Similarly,
N-methyl-N-phenyl(ch1oromethy1)phenylphosphinamide
(15) was cyclized to give
1-methyl-2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole2-oxide (1 3b). Some unsuccessful approaches
to this heterocyclic ring system are also reported.
A practical route to alcohols in the 7,7-Dimethylbenzonorbornene (9,9-Dimethyl-1,4-methanonaphthalene) series
Authors: Russell RA , Harrison PA , Warrener RN
Published: September 2010

The previously undescribed exo-and endo-7,7-dimethylbenzonorbornen-5-ols,
can be prepared by the selective hydrogenolysis of the central unsubstituted
bond in the corresponding spirocyclopropyl derivatives. Other examples of the
reaction are also described.
Crystal structure of ethylenediammonium hexaaquanickel(II) sulfate: a variation on the Tutton salts
Authors: Healy PC , Patrick JM , White AH
Published: September 2010

The crystal structure of
the title complex, [H3NCH2CH2NH3]
[Ni(H2O)6] [SO4]2, has been determined
by single-crystal X-ray diffraction methods at 295 K, being refined by full
matrix least squares to a residual of 0.032 for 2532 independent 'observed'
reflections. Crystals are monoclinic, P21/n, a 13.148(3), b 7.119(3), c 8.245(2) �, β 100.97(4)�, Z = 2.
Both cations are disposed about crystallographic centres of symmetry. The
organic species has a necessarily planar non-hydrogen atom skeleton [C-C,
1.513(3); C-N, 1.485(4) �]. In the hexaaquanickel(11) species, the Ni-O
distances are very similar [2.060(2), 2.064(2), 2.066(2) �], although there is
a significant departure from octahedral symmetry among the angles [89.71(8),
86.87(8), 90.00(8)�]. The oxygen atoms of the water molecules are bonded
pseudo-tetrahedrally. The centrosymmetric metal atom environment is more
regular than that in the corresponding Tutton salts, to which complexes of the
present type may present an attractive alternative.
Molecular geometry and crystal structure of 9-acetylanthracene
Authors: Anderson K , Becker H , Engelhardt LM , Hansen L , White AH
Published: September 2010

The molecular geometry of
9-acetylanthracene has been established by X-ray diffraction analysis. The
acetyl group is twisted out of the plane of the aromatic π-system by 88�. The intermolecular geometry in
crystalline 9-acetylanthracene is characterized by head-to-tail pairs with an interplanar distance of 3.42 � between parallel aligned
anthracene moieties. Parallel adjacent molecules of 9-acetylanthracene deviate
from perfect overlap by a long-axis shift of 1.35 �, and a short-axis shift of
0.88 �.
The X-ray crystal structure of 4-t-Butyl-r-2-(4'-t-butyl-2',6'-dimethyl-phenoxy)-t-6-hydroxy-2,6-dimethyl-t-5-nitrocyclohex-3-enone
Authors: Hartshorn MP , Sutton KH , Vaughan J
Published: September 2010

The X-ray crystal structure
determination of 4-t-butyl-r-2-(4'-t-butyl-2',6'-dimethylphenoxy)-t-6-
hydroxy-2,6-dimethyl-t-5-nitrocyclohex-3-enone (3) is reported. This compound
is formed by reaction of 4-t-butyl-2,6-dimethylphenol(1) with nitrogen dioxide (1
mol) in benzene, followed by removal of the benzene under reduced pressure.
N.M.R. studies of myelin basic protein. XII. Spectra in aqueous solution of a synthetic octapeptide encephalitogenic in the Lewis rat
Authors: Bremer J , Moore WJ
Published: September 2010

A synthetic peptide Ala-Gln-Arg-Pro-Gln-Asp-Glu-Asn encephalitogenic
in the Lewis rat has been studied in aqueous solutions by 1H and 13C
n.m.r. The configuration about the Arg-Pro peptide bond
is > 99% trans. The temperature dependences and titration shifts of NH
resonances areconsistent with occurrence
of a number of intramolecular hydrogen bonds, leading to an unusually compact
structure for a linear peptide in aqueous solution.
Chemical constituents of the Flindersia. XXIII. Determination of the structure of flindercarpin-2 as methyl (S)-(Acetoxy){[3'S-(3α,3aα,4α,5β,6α,6aα,7α,10aα,11aα)]-5',6'-diacetoxy-7'-(furan-3'-yl)-2',2',3a',6a', 11a'-pentamethyl-12'-methylene-9'-oxo-2',3',3a',4',5',6',6a',9', 10', 11a'-decahydro-7'H-4', 10a'-methano-10a'H-furo[2,3-b]pyrano[3,4-g]oxocin-3'-yl)acetate
Authors: Breen GW , Picker K , Raston CL , Skelton BW , Taylor WC , White AH
Published: September 2010

Flindercarpin-2, C32H40013,
isolated from the bark of Flindersia laecicarpa C.T. White & Francis (Rutaceae) was shown by spectroscopic and crystallographic
studies to be a pentanortriterpenoid, methyl (S)-(acetoxy){[3'S-(3α,3aα,4 α,5β,6α,6aα,7α,10aα,11aα)]-5',6'-diacetoxy-7'-(furan-3??-yl)-2',2'-3a',6a',11a'-pentamethyl-12'-methylene-9'-oxo-2',3',3a',4',',6',6a,9',10'
11a'-decahydro-7'H-4',10a'-methano-10a'H-furo[2,3-b]pyrano[3,4-g]oxocin-3'-yl}acetate
(2).