bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical and spectroscopic studies in metal β-diketonates. II. Nitration of metal β-diketonates
Authors: Singh PR , Sahai R
Published: September 2006

Bis(3-nitropentane-2,4-dionato)-beryllium(II),
-copper(II), and - palladium(II); tris(3-nitropentane-2,4-dionato)-aluminium(III),
- chromium(III), -manganese(III), -iron(III), and -cobalt(III); tetrakis(3-nitropentane-2,4-dionato)zirconium(IV);
and tris (3-nitro- 1,3-diphenylpropane-1,3-dionato)-aluminium(III) and
-chromium(III) have been prepared by the nitration of the respective metal
chelates of acetylacetone and 1,3-diphenylpropane-1,3-dione. Ferric nitrate,
cobaltous nitrate, and nickel nitrate have been used as nitrating agents for
the first time. The nitro chelates have also been prepared by a direct,
single-step process using metal nitrates, acetic anhydride, and the ligands. In
several cases, metal replacement reactions have been observed to be taking
place in conjunction with nitration under nitration reaction conditions.
Infrared, ultraviolet, and visible electronic spectra have been recorded and
are discussed.
An infrared spectroscopic study of certain Di(3,5,5-trimethylhexyl)ammonium salts
Authors: Cattrall RW , West BO
Published: September 2006

The band associated with
the N-H stretching vibration for the simple amines is usually well defined at a
single frequency. However, the bands for the alkyl ammonium salts are quite
complex, and the numbers, intensities, and positions of these bands are determined
by the interactions of the protons associated with the ?NH+2
group with the anion. Large interactions lead to considerable lowering in the
N-H stretching frequencies. For the alkylammonium sulphates this interaction
also affects the number of frequencies observed for the sulphate group.

When the alkylammonium sulphate is
complexed to iron(III), in a complex of the stoicheiometric formula (R2NH2)2FeOH(SO4)2, the infrared
spectrum is consistent with much weaker interaction between the alkylammonium
protons and the anion.
Organic compounds of samarium. Reactions of samarium isopropoxide with acetylacetone and benzoylacetone
Authors: Sankhla BS , Kapoor RN
Published: September 2006

A detailed study has been
made of the reactions between samarium isopropoxide and acetyl and
benzoylacetones in the presence of benzene. The reactions with acetylacetone
are all exothermic, yielding products which are sparingly soluble in benzene.
The mixed isopropoxide acetyl or benzoylacetone derivatives have also been
prepared in almost quantitative yield. A plausible reaction mechanism has been
suggested.
Electron impact studies. VI. Mass spectra of esters and thioesters. Skeletal rearrangement on electron impact
Authors: Bowie JH , Cooks RG , Jakobsen P , Lawesson S , Schroll G
Published: September 2006

The mass spectra of
representative series of simple alkyl acetoacetates, alkyl acetothioacetates,
and some unsaturated esters derived from unsaturated alcohols or phenols are
reported and discussed. The fragmentation schemes have been established by high
resolution measurements, appropriate metastable ions, and by deuterium and 18O
labelling. Many of the spectra show significant skeletal rearrangement
fragments arising from either loss of carbon monoxide or carbon dioxide.
Structural changes of flavylium salts. II. Polargographic and spectrometric investigation of 4'-Hydroxyflavylium perchlorate
Authors: Harper KA , Chandler BV
Published: September 2006

4?-Hydroxyflavylium
perchlorate is examined polarographically and spectrometrically
in aqueous methanolic solution over a wide pH range. In solutions below pH 3
the flavonoid moiety exists solely as the flavylium ion, which establishes an
equilibrium with the pseudobase, the anhydrobase, and the 2-hydroxychalcone
above this pH. The flavylium ion disappears from solution above pH 5, the
anhydrobase remains at a constant low concentration, and the ratio of
pseudobase to chalcone fluctuates as the pH is increased. Electrode reactions
for the various reductions are the same as those previously described for 7,4?-
dihydroxyflavylium perchlorate. Without influencing the polarographic
reduction, the presence of mercury in the polarographic cell favours chalcone
formation in neutral solutions and suppresses resonance in the chalcone ion at
high pH, probably through formation of a mercuric chelate.
Alkaloids of Crotalaria trifoliastrum Willd. and C. aridicola Domin. III. Additional pyrrolizidine derivatives
Authors: Culvenor CCJ , O'Donovan GM , Smith LW
Published: September 2006

Two new alkaloids are
described, 1β,2β-epoxy-1a-hydroxymethyl-8a-pyr-
rolizidine (IV), from C. trifoliastrum Willd. and
7β-acetoxy-1- methoxymethyl-1,2-dehydro-8a-pyrrolizidine (VI), from C. aridicola Domin. 7-Hydroxy-1-methoxy-
methyl-1,2-dehydro-8a-pyrrolizidine (V) is also present in C. trifoliastrum and
is shown to be identical with a base reported previously from C. medicaginea Lamk. All three bases
are partially synthesized from commonly available amino alcohols. The
occurrences of these and previously identified alkaloids in the morphologically
distinguishable forms of C. trifoliastrum are discussed.
The adsorption of ethylene oxide on silver(I) oxide
Authors: Allen JA , Scaife PH
Published: September 2006

The adsorption of ethylene
oxide on stabilized silver(I) oxide in the temperature range 210-373% comprises
two processes:

(i) A non-activated process with a heat of
adsorption from 10.7 to 6.9 kcal mole-l depending on the coverage, which
persists over the entire temperature range; ��� (ii) an activated process with an
activation energy at zero coverage of 22.7 kcal mole-1, which occurs
at temperatures greater than 250�K.

Reaction between adsorbate and adsorbent
ensues above 323%. The generalized Elovich equation
has been found to apply to the activated process at high coverage, and an
explanation for this is proposed.
Studies in the stereochemistry of zinc(II). V. Zinc complexes with N-alkylsalicylaldimines
Authors: Batley GE , Graddon DP
Published: September 2006

Bis(N-alkylsalicylaldiminato)zinc(II)
complexes are monomeric and 4- coordinate in dilute solutions in toluene but
some association is observed in concentrated solutions in diphenylamine.
Spectroscopic studies in the ultraviolet region show that only the methyl and
ethyl homologues form 5-coordinate pyridine adducts even in pyridine solutions.
Only the methyl homologue forms a pyridine adduct stable enough to be isolated,
and only this homologue forms a 5-coordinate dimer in the solid state. The
ultraviolet reflectance spectra and infrared spectra of the solid compounds can
be used to distinguish those compounds in which some or all of the phenolic
oxygen atoms are bridging: such bridging is accompanied by a splitting of the
ultraviolet absorption near 370 mμ and a shift
of a very sharp infrared band from 1530 to 1550 cm-1. This band is
tentatively assigned to the phenolic C-O stretching mode.
Photochemical reactions of azo compounds. X. Photochemical properties of azobenzene-2-carboxylic acids
Authors: Joshua CP , Lewis GE
Published: September 2006

Two chloro and two methyl
derivatives of azobenzene-2-carboxylic acid have been found to yield the
corresponding derivatives of benzo[c]cinnoline-4- carboxylic acid in good
yields when irradiated in 98% sulphuric acid. The question of intramolecular
hydrogen bonding in relation to the properties of azobenzene-2-carboxylic acids
is discussed. Infrared absorption spectra of the neutral compounds have
provided confirmation of internal hydrogen bonding. Attempts to prepare the cis
isomers of these azo compounds have been unsuccessful.
The chemistry of pyrrolic compounds. IV. β-Hydroxy- and β-Methoxypyrroles
Authors: Chong R , Clezy PS
Published: September 2006

Some aspects of the
chemistry of β-hydroxypyrroles and their methyl ethers are described, with
particular reference to the development of pyrrolic intermediates suitable for
the synthesis of porphyrins carrying this type of substituent. Tautomerism in
the β-hydroxypyrroles is discussed.
The chemistry of pyrrolic compounds. VI. Chlorins and related compounds
Authors: Chang Y , Clezy PS , Morell DB
Published: September 2006

A novel bromination of
porphyrins is described in which a compound of the chlorin class is produced.
Evidence is presented in support of structure (VIa)
for this compound. Mesochlorin and deuterochlorin have been prepared as model
compounds during this investigation, and it has been shown by N.M.R.
spectroscopy that both these chlorins have been reduced in either rings A or B
and not in ring D as occurs in the chlorophylls a and b.
Diterpenes of Dacrydium bidwillii
Authors: Grant PK , Huntrakul C , Sheppard DRJ
Published: September 2006

Examination of the
heartwood of Dacrydium bidwillii has shown the
presence of isopimara-7,15-diene, isopimaradienal, isopimaradienol, manool,
torulosol, β-sitosterol, and isopimaric acid. A nor-diterpene isolated was
shown to be 18-nor-isopimaradien-4a-ol (I), and this was confirmed by its
synthesis from isopimaradienal.
The chemical constituents of Galbulimima species. VI. The structure of himandridine
Authors: Mander LN , Ritchie E , Taylor WC
Published: September 2006

Himandridine, the major alkaloid
of the ester group of Galbulimima alkaloids, was
shown to have the hexacyclic structure (III) by systematic characterization of
the functional groups and by rational degradation to the (+)-1-lutidyl-4-methylbenz[e]indan
(XLI), the racemic modification of which was synthesized. ��� Himandridine and himbosine are the first
members of a new alkaloid family.
The chemical constituents of Galbulimima species. VII. The correlation of himandridine and himbosine
Authors: Mander LN , Ritchie E , Taylor WC
Published: September 2006

Additional support for the
structure of himandridine (I) was obtained by a correlation, via the ketone (Vb), with himbosine (II), whose structure was already known
from an X-ray crystallographic study.
Molecular force field for thionyl fluoride and sulphuryl fluoride
Authors: Pichai R , Pillai MGK , Ramaswamy K
Published: September 2006

The potential energy
constants of thionyl fluoride and sulphuryl fluoride were calculated using a
modified UBRF. The behaviour of the oxygen atom is found to be similar to that
of the lone pair of electrons in thionyl fluoride. The vibrational mean amplitudes
of thionyl fluoride and sulphuryl fluoride were also calculated from the
vibrational spectral data.
Sucrose crystal growth. II. Rate of crystal growth in the presence of impurities
Authors: Smythe BM
Published: September 2006

The effects are described
of supersaturation, temperature, and relative motion of solution and crystal on
the rate of sucrose crystal growth from aqueous solutions containing a wide
range of impurities. The
results are consistent with the conclusion, drawn from data in pure sucrose
solution, that two main steps, neither of which are clearly rate-controlling
under the experimental conditions, are important in crystal growth kinetics.

Impurities can be classified broadly as
those which have their main effect on the mass transfer of sucrose from the
bulk of the solution to the site of incorporation on the sucrose crystal, and
those which exert their main effect by surface adsorption, hindering the
incorporation of sucrose into the crystal lattice.
Sucrose crystal growth. III. The relative growth rates of faces and their effect on sucrose crystal shape
Authors: Smythe BM
Published: September 2006

Graphical projections of
sucrose crystal structure along the three principal crystallographic axes are
presented. The packing of sucrose molecules at crystal surfaces shown by these
projections is important in determining the relative growth rates of the various
faces and the manner in which these are influenced by impurities.

Relative growth rates of eight principal
forms of the sucrose crystal in pure sucrose solutions are compared with those
in the presence of impurities. This shows that the dominant factor in the
influence of impurities on the relative growth rates of the faces of the
sucrose crystal, and the concomitant effect on sucrose crystal shape, is the
stereospecific adsorption of these impurities at kink sites on the growing
crystal surface.
Solvent effects on the conformations of ortho-nitroanilines
Authors: Rae ID
Published: September 2006

Proton magnetic resonance
spectroscopy has been used to examine the conformations of a number of
ortho-nitroanilines in solution. In solvents of low polarity, intramolecular
hydrogen bonding maintains the coplanarity of the nitro group and the aromatic
ring, but in more polar solvents the nitro group is rotated from the ring plane
and this change is evidenced by an upfield shift in the resonance position of
the adjacent aromatic proton. The extent of rotation depends on the polarity of
the solvent and on the structure of the amine.
The mass spectra of acridones
Authors: Bowie JH , Cooks RG , Prager RH , Thredgold HM
Published: September 2006

The mass spectra of 34
acridones have been determined and interpreted with the aid of both
high-resolution measurements and deuterium labelling studies. The spectra
contain pronounced molecular ions and are free of skeletal rearrangement
fragments. The fragmentation patterns are dependent on the nature and position
of substituents, and therefore mass spectrometry can be a useful aid to structure
determination in this class of naturally occurring compounds.
N.M.R. spectra and stereochemistry of the bipyridyls. III. 2,2'-Bipyridyl and dimethyl derivatives, 3,3'- bipyridyl, and 4,4' - bipyridyl
Authors: Spotswood TM , Tanzer CI
Published: September 2006

The analysis of the n.m.r,
spectra of 2,2?-, 3,3?-, and 4,4?-bipyridyl and three dimethyl-2,2?-bipyridyls
is reported and the factors determining the relative chemical shifts of the
ring protons and methyl groups in several solvents are discussed. The diamagnetic
anisotropy of the neighbouring ring and electrostatic field effect of the
nitrogen lone pair electrons are shown to be of roughly equal importance for
derivatives of 2,2?-bipyridyl except in hydrogen bonding solvents. Attenuation
of the electrostatic field effect in polar, and particularly in hydrogen
bonding solvents, is established for 4- picoline, and for the bipyridyls, and
this effect is responsible for striking changes in the spectrum of 2,2?-bipyridyl
in hydrogen bonding solvents. An approximate interplanar angle of 58� is
derived for 3,3?- dimethyl-2,2?-bipyridyl, and 2,2?-bipyridyl and its 4,4?- and
5,5?- dimethyl derivatives appear to be trans coplanar in all solvents. 3,3?-
Bipyridyl and 4,4?-bipyridyl are probably highly twisted in all solvents, or
alternatively, behave as essentially free rotors. The predicted conformations
are in good agreement with the electronic spectral data.
Characterization of the cleavage products of human serum immunoglobulin disulphide bonds. II. S-Cyano derivatives
Authors: Brackenridge CJ
Published: September 2006

The displacement by cyanide ions of S-sulpho substituents from sulphitolysed
human serum immunoglobulins yielded S-cyano derivatives, the solubility and
sedimentation characteristics of which were examined with respect to pH.
Exclusion chromatography gave rise to an aggregated and an unaggregated fraction
in proportions similar to those found after oxidative sulphitolysis.
Evidence obtained from immunoelectrophoresis, N-terminal amino acid
assay, and hexose and amino acid analysis showed that both S-cyano fractions
contained polypeptide chains in the same ratios as in the native protein.
Alkaloids of Phoebe clemensii Allen (family Lauraceae)
Authors: Johns SR , Lamberton JA
Published: September 2006

The leaf alkaloids of
Phoebe clemensii Allen consist of the known aporphine
alkaloid isocorydine, and two new aporphines, 10-hydroxy-1,2-
methylenedioxy-aporphine and 2,11-dihydroxy-1,10-dimethoxyaporphine.
The bark alkaloids of P. clemensii consist largely of
the one aporphine alkaloid laurolitsine.
The effect of pressure on cyclic reactions
Authors: Ewald AH , Ottley DJ
Published: September 2006

Rates of the cyclization of
4-chlorobutanol and of some analogous non- cyclic solvolysis reactions have
been measured in water, methanol, and aqueous acetone at pressures up to 3000
atm. The volume of activation of the cyclic reaction is less negative than
those of the linear reactions, in each solvent, but it is suggested that the
transition states of both types of reaction may be solvated to about the same
extent. The volume of activation for the formation of an eight-membered ring in
the cyclization of 4-bromobutylcatechol monoether was
also determined.
Phase diagram for ethylene glycol and triethylamine
Authors: Davids EL , Findlay TJV
Published: September 2006

The liquid-liquid phase
diagram for ethylene glycol and triethylamine has been determined. This mixture
has a lower consolute temperature of 57.7 � 0.1� at 0.45 � 0.1 mole fraction
triethylamine. Both carbon dioxide and water lower the lower consolute temperature.
The densities and viscosities of solutions just below the lower consolute
temperature do not exhibit any abnormalities.
Organomercury compounds. IV. Infrared spectra, structures, and thermal decomposition of mercuric arylsulphinates
Authors: Deacon GB
Published: September 2006

The structures of mercuric
benzenesulphinate and p-toluenesulphinate have been investigated by infrared
spectroscopy, and it has been shown that the arylsulphinate ions are
coordinated to mercury through sulphur and not through oxygen. Thermal
decomposition of the benzenesulphinate, at the melting point or in toluene,
gives good yields of diphenylmercury. No di-p-tolylmercury
is obtained from pyrolysis of the p-toluenesulphinate in absence of a solvent,
but a moderate yield is obtained when the compound is decomposed in boiling
toluene.
Some unusual complexes of iron with 1,10-phenanthroline and 2,2'-bipyridyl
Authors: Driver R , Walker WR
Published: September 2006

The following
hydroxy-bridged iron(III) complexes have been isolated for the first time : [phen2 Fe(OH)2Fe
phen2](SO4)2,7H2O,
[phen2 Fe(OH)2Fe
phen2]Br4,2H2O,
[bipy2 Fe(OH)2Fe
bipy2](SO4)2,9H2O.
Attempts to prepare thiocyanate derivatives of these complexes resulted
unexpectedly in the synthesis of the compounds Fe(SCN)2 phen2,H2O and [FeSCN
phen2]ClO4
which were investigated in the light of the well-known complexes of the type FeX2 chelate2.
The compound [Fe phen3][Fe(CN)4
phen],5H2O which, except for water, has
the same stoicheiometry as Fe(CN)4 phen2,
is also described for the first time.

The claim by Madeja
(Chemicke Zvesti, 1965, 19,
186) that the compound Fe(SCN)2 bipy2
exists both as a red trans form (μeff 3.0 B.M.) and a violet
cis form (μeff 5.2 B.M.) is not justified according to this
work. It seems that the red form may be a mixture of the paramagnetic bis- and
the diamagnetic tris-compounds.
Antioestrogenic and antifertility compounds. I. 2-(NN-Dialkylamino)ethyl ethers of some stilbene-4,4'-diol and 4,4'-dihydroxybibenzyl derivatives
Authors: Collins DJ , Hobbs JJ
Published: September 2006

A series of α-methyl-
and α,α?-dimethyl-stilbene and -bibenzyl compounds substituted in the
4,4?-positions with a hydroxyl (or methoxyl) group and a 2-(NN-dialkylamino)ethoxyl
group has been synthesized to be tested for antioestrogenic and antifertility
activity. The corresponding bis-2-(NN-dialkylamino)ethyl ethers are also
described.
Reactions of 3,4-dehydroproline and 4-chloroprolines with ninhydrin, isatin, and cyclic α-diketones
Authors: Hudson CB , Robertson AV
Published: September 2006

3,4-Dehydro-DL-proline
reacts with a number of a-dicarbonyl compounds to form products in which the
pyrroline ring is converted into an N- substituted pyrrole. Depending on the
reactivity of the α-dicarbonyl compound, a second molecule may (e.g.
ninhydrin) or may not (e.g, isatin) react further by
α-substitution of the pyrrole. The structures of the products account for
the different colour reactions of dehydroproline compared with proline. cis-
and trans-4-Chloro-L-proline yield the same products as dehydroproline with
ninhydrin and isatin.
The reaction of free radicals with trichlorosilane
Authors: Bell TN , Johnson BB
Published: September 2006

Trifluoromethyl radicals
generated from the photolysis of hexafluoroacetone abstract hydrogen atoms from
trichlorosilane; the competitive abstraction of chlorine atoms does not occur
under the experimental conditions. The rate of the abstraction

������� �����������������CF3 + SiHCl3 → CF3N + SiCl3

has been measured in
comparison with the known rate for the recombination of trifluoromethyl
radicals, to yield a rate constant,

������������������ k = 1012.13exp(-6850/RT)
ml mole-1 sec-1

Methyl radicals similarly
abstract hydrogen to yield methane. A quantitative study of this reaction
proved impractical, due to complications using acetone as a radical source.
The thermal decomposition of 1-ethoxyethyl chloride and the reverse combination
Authors: Failes RL , Stimson VR
Published: September 2006

1-Ethoxyethyl chloride
decomposes cleanly at 164-221� into vinyl ethyl ether and hydrogen chloride in
a first-order manner with

k1 = 1010.52exp(-30300/RT) sec-1 (1)

The equilibrium of the
system at 128-221� approached from either direction at various pressures is well
represented by (Kp in atmospheres)

1.987 In Kp = 31.1 �
0.9-(16500�500)/T (2)

and this leads to ΔH�f,298(g) = -71.9 kcal mole-1
for 1-ethoxyethyl chloride. Combination of (1) and (2) gives

k2 = 108.7exp(-14700/RT) sec-1 ml mole-1

for the reverse reaction
and rate measurements verify this. The reactions are molecular, and relative
rates indicate a polar transition state.
Reactivity in the system carbon-hydrogen-methane
Authors: Blackwood JD , Cullis BD , McCarthy DJ
Published: September 2006

Experimental work has shown
that the rate constant k* = R/p1 (where R is the rate of methane
formation and p1 is the hydrogen partial pressure) for the forward
reaction, C + 2H2 ↔ CH4, is a function of the
temperature of char preparation and reaction and can be expressed by

���������������������� k* = w
exp(b/Tp)exp(-c/Tp)

where w, b, and c are
constants; Tp and Tg are the temperatures, in �K, of char
preparation and gasification respectively; and Tg≤Tp.
Chars which have been gasified at a given temperature and then exposed to a
higher temperature do not show their initial reactivity when returned to the
lower temperature. The deactivation of the char, as evidenced by a measurable
decrease in active surface area, is a non-reversible process. Approximate values
of the active surface area per unit mass of char have been calculated, and a
linear relationship between reactivity and active surface area has been found
experimentally. Both the forward and reverse processes proceed by chemisorption
of either methane or hydrogen on the same type of active site, and the nature
of the sites is unchanged by temperature, although their number decreases with
increasing temperature and as a result, the equilibrium is independent of char
type. The value of the heat of adsorption of hydrogen on carbon, calculated
from the experimental results, was approximately 7 kcal mole-1.
Tritertiary arsine complexes of titanium(IV) and zirconium(IV) halides
Authors: Barclay GA , Gregor IK , Lambert MJ , Wild SB
Published: September 2006

Compounds formed by the
tritertiary arsine ligand methylbis(3-dimethyl- arsinylpropyl)arsine
(tas) with titanium tetrahalides (where the halide is
F, Cl, Br, or I) and zirconium tetrabromide are
described. Titanium and zirconium tetrabromide yield isomorphous crystals of
the neutral diamagnetic complexes (MBr4 tas), which are believed to be seven- coordinate, The
complexes [(TiF4)3 tas], [(TiCl4)2
tas], and [TiI3 tas]I have been isolated and their physical properties and
possible structures are discussed.
Carboxylato derivatives of Bis(cyclopentadienyl)titanium(III)
Authors: Coutts RSP , Wailes PC
Published: September 2006

Several carboxylato
derivatives of bis(cyolopentadienyl)titanium(III), of
general formula cp2TiOOCR, have been
prepared by precipitation from air-free aqueous solutions of cp2TiCl (cp = C5H5). The
compounds are blue or green and paramagnetic, having one unpaired electron per
titanium atom. All of the available evidence indicates that the carboxylato
ligands are bidentate, symmetrical, and covalently bound to the metal.
Preparations and infrared spectra of some metal pentachlorobenzoates
Authors: Deacon GB , Felder PW
Published: September 2006

The pentachlorobenzoates, NaOCOC6Cl5,2H2O, KOCOC6Cl5,H2O, MOCOC6Cl5 (M = Cs or Tl), Hg(OCOC6Cl5)2, RHgOCOC6Cl5 (R = Ph or p-MeOC6H4), and R3SnOCOC6Cl5
(R = Ph or Me) have been prepared by neutralization, metathesis, or cleavage
reactions. Vibrational assignments have been made for infrared absorption
frequencies of, these compounds, pentachlorobenzoic acid, bispenta-chlorophenylmercury,
and pentachlorophenylmercuric chloride. The
carboxylate stretching frequencies indicate that Hg(OCOC6Cl5)2,
RHgOCOC6Cl5, and R3SnOCOC6Cl5 (in
chloroform) have unidentate pentachlorobenzoate ligands, whereas crystalline R3SnOCOC6Cl5 compounds
have bridging pentachlorobenzoate groups. Pentachlorobenzoic acid is dimeric in
the solid state, and in toluene, carbon tetrachloride, and benzene there are
both monomeric and dimeric species.
The SN mechanism in aromatic compounds. XXXVI. Reactivity of monochlorodiazabenzenes
Authors: Chan TL , Miller J
Published: September 2006

An investigation has been
made of the reactions of p-nitrophenoxide ion in methanol with equimolar
quantities (0.01-0.02M) of the six monochlorodiaza-benzenes,
viz. 3- and 4-chloropyridazine (1,2- diazabenzene);
2-, 4-, and 5-chloro-pyrimidines (1,3-diazabenzene); and 2-chloropyrazine
(1,4-diazabenzene) in the presence of a tenfold excess (0.1-0.2M) of
p-nitrophenol.

Results have been compared with earlier
results from the pyridine series, and reactivity shown to be in reasonable
agreement with that predicted from kinetic data for the pyridine series
assuming independent activation by each nitrogen.

There is evidence for mild acid catalysis
by the p-nitrophenol added to prevent concurrent methanolysis. It is estimated
that this leads to an increase in Hammett substituent constant (σ-) values
of only 0.2 units or less.

The reactivity order is 2- > 4-chloro-N-methylpyridinium > 2- > 4- chloro-pyrimidine > 4-chloropyridazine≈3-chloropyridazine≈2-
chloropyrazine>3-chloro-N-methylpyridinium≈5-chloropyrimidine,
and this corresponds with the theoretical order as modified by mild acid
catalysis, more effective in the order ortho-> meta- > para- to the point
of substitution, and including the inverted order, 2- > 4- chloropyrimidine,
whereas the usual reactivity order with anionic reagents is 4- > 2-chloropyrimidine.
Hydropyrimidines. V. Hexahydropyrimidines. The reaction of aldehydes and ketones with 1,3-diaminopropanes
Authors: Evans RF
Published: September 2006

Hexahydropyrimidine and some N-alkylated derivatives have been obtained
from the reaction of the corresponding trimethylenediamine or its
monoprotonated salt with formaldehyde. A variety of spectroscopic evidence
supports a cyclic structure for these compounds in preference to a tautomeric
open-chain form. The chemical behaviour of hexahydropyrimidine
is explicable in terms of a cyclic di-secondary amine structure.

The cyclic structure is destabilized with
respect to the open- chain form if the hydrogen atoms attached to C2 of the hexahydropyrimidine ring are replaced by alkyl groups and
cannot be detected when, in addition, one of the hydrogen atoms attached to
nitrogen is replaced by the bulkier t-butyl group.

Hexahydro-2-methylpyrimidine is dehydrogenated
to 1,4,5,6- tetrahydro-2-methylpyrimidine on shaking with Adams catalyst and
hydrogen under laboratory conditions. Hexahydropyrimidines
which are tautomeric mixtures are reduced to the corresponding N-alkyl-1,3- diaminopropanes,
while those possessing cyclic structures are inert.
Reduction of certain oxindoles and isatins with lithium aluminium hydride
Authors: Hudson CB , Robertson A.V.
Published: September 2006

Reduction by lithium
aluminium hydride of the adducts from the interaction of 3,4-dehydroproline and
various isatins is described. The parent mono-adduct, 3-(1-pyrrolyl)oxindole,
is normally inert but yields indole under special conditions. The 1-methyl and
1-ethyl analogues give mixtures of the corresponding 3-(1-pyrrolyl)-indoles and
3-(1-pyrrolyl)indolines. These indolines are extremely weak bases. The
di-adduct from 1-methylisatin gives products which confirm its hemiacetal
structure.
The chemical constituents of Galbulimima species. X. The structure of himgaline
Authors: Mander LN , Prager RH , Rasmussen M , Ritchie E
Published: September 2006

The structure (III)
proposed for the hexacyclic alkaloid, himgaline, on the basis of chemical and
spectroscopic characterization was confirmed by several partial syntheses of
himgaline derivatives from de-N-methylhimbadine (alkaloid G.B. 13).

The biogenesis of the Galbulimima
alkaloids is discussed.
A re-examination of Evodia alata F. Muell. The structure and synthesis of evoprenine, a new acridone alkaloid
Authors: Diment JA , Ritchie E , Taylor WC
Published: September 2006

The known alkaloids,
evoxanthine, melicopidine, 1,2,3-trimethoxy-10- methylacridan-9-one, its
1-demethyl derivative, and kokusaginine have been isolated from the bark of
Evodia data collected in New Guinea, together with a new alkaloid, evoprenine.
By synthesis from evoxanthine, evoprenine was shown to be 1-hydroxy-2-methoxy-3-[(3-
methylbut-2-enyl)oxy]-10-methylacridan-9-one. Some aspects of the N.M.R. and
mass spectrometry of acridone derivatives are discussed.
1-Benzyl-1,2,3,4-tetrahydroisoquinoline alkaloids from Alseodaphne archboldiana (Allen) Kostermans (family Lauraceae)
Authors: Johns SR , Lamberton JA , Sioumis AA
Published: September 2006

The alkaloids of Alseodaphne archboldiana (Allen) Kostermans of the family Lauraceae are 1-benzyl-1,2,3,4-tetrahydroisoquinolines, and
they have been shown to be (-)-N-norarmepavine, (+)-reticuline, and both (+)
and (-)-coclaurine. (+)-Coclaurine isolated from Xylopia
papuana has been shown to be close to optical purity, and comparison with it
indicates that the mixture of coclaurine optical isomers from A. archboldiana
consists of (+)-coclaurine and (-)-coclaurine in the approximate ratio 3 : 1.
Useful structural information can be derived from the N.M.R. spectra of
N-acetyl compounds prepared from coclaurine and N-norarmepavine.
1,5-Dimethoxy-3-(dimethylaminomethyl)indole, the major alkaloid from Gymnacranthera paniculata (A. DC.) Warb. var. zippeliana (Miq.) J. Sinclair (family Myristicaceae)
Authors: Johns SR , Lamberton JA , Occolowitz JL
Published: September 2006

The major alkaloid of Gymnacranthera paniculata (A.
DC.) Warb. var. zippeliana
(Miq.) J. Sinclair (Family Myristicaceae) has been
identified as 1,5- dimethoxy-3-(dimethylaminomethyl)indole
(I), and a minor alkaloid as N,-methyl-tetrahydro-β-carboline (VI).
Advanced glycation end product (AGE) receptor 1 suppresses cell oxidant stress and activation signaling via EGF receptor
Authors: Cai Weijing , He John C. , Zhu Li , Lu Changyong , Vlassara Helen
Published: September 2006

Advanced glycation end product receptors (AGERs) play distinct functional roles in both the toxicity and disposal of advanced glycation end products (AGEs), substances that are linked to diabetes and aging. Overexpression of AGER1 in murine mesangial cells (MCs) (MC-R1) inhibited AGE-induced MAPK1,2 phosphorylation and NF-κB activity and also increased AGE degradation. The mechanism of the inhibitory effects of AGER1, upstream of MAPK, was explored in MCs and HEK293 AGER1-expressing cells. AGE-induced Ras activation was found to be linked to Shc/Grb2 complex formation and Shc phosphorylation in MCs, responses that were markedly reduced in MC-R1 cells. AGE responses also included EGF receptor (EGFR) phosphorylation in MCs or HEK293 cells, but this link was blocked in both MC-R1 and HEK293-R1 cells. Coexpression of AGER1 and EGFR in HEK293 cells decreased AGE-mediated EGFR and p44/p42 phosphorylation but not EGF-induced p44/p42 activation. AGE, S100/calgranulin, or H
2
O
2
promoted MAPK phosphorylation in EGFR
+
cells in a manner that was inhibitable by an EGFR inhibitor, AG1478. Also, in AGER1 cells, AGE-induced H
2
O
2
formation and AGE- or S100-induced p44/p42 phosphorylation were suppressed, and these effects were restored by R1 siRNA. These data confirm that R1 negatively regulates AGE-mediated oxidant stress-dependent signaling via the EGFR and Shc/Grb2/Ras pathway. AGER1 could serve as a model for developing therapeutic targets against vascular and kidney disorders related to diabetes and aging.
Swimming efficiency of bacterium
Escherichia
coli
Authors: Chattopadhyay Suddhashil , Moldovan Radu , Yeung Chuck , Wu X. L.
Published: September 2006

We use measurements of swimming bacteria in an optical trap to determine fundamental properties of bacterial propulsion. In particular, we directly measure the force required to hold the bacterium in the optical trap and determine the propulsion matrix, which relates the translational and angular velocity of the flagellum to the torques and forces propelling the bacterium. From the propulsion matrix, dynamical properties such as torques, swimming speed, and power can be obtained by measuring the angular velocity of the motor. We find significant heterogeneities among different individuals even though all bacteria started from a single colony. The propulsive efficiency, defined as the ratio of the propulsive power output to the rotary power input provided by the motors, is found to be ≈2%, which is consistent with the efficiency predicted theoretically for a rigid helical coil.
Differential impact of Ink4a and Arf on hematopoietic stem cells and their bone marrow microenvironment in Bmi1-deficient mice
Authors: Oguro Hideyuki , Iwama Atsushi , Morita Yohei , Kamijo Takehiko , van Lohuizen Maarten , Nakauchi Hiromitsu
Published: September 2006

The polycomb group (PcG) protein Bmi1 plays an essential role in the self-renewal of hematopoietic and neural stem cells. Derepression of the Ink4a/Arf gene locus has been largely attributed to Bmi1-deficient phenotypes in the nervous system. However, its role in hematopoietic stem cell (HSC) self-renewal remained undetermined. In this study, we show that derepressed p16Ink4a and p19Arf in Bmi1-deficient mice were tightly associated with a loss of self-renewing HSCs. The deletion of both Ink4a and Arf genes substantially restored the self-renewal capacity of Bmi1−/− HSCs. Thus, Bmi1 regulates HSCs by acting as a critical failsafe against the p16Ink4a- and p19Arf-dependent premature loss of HSCs. We further identified a novel role for Bmi1 in the organization of a functional bone marrow (BM) microenvironment. The BM microenvironment in Bmi1−/− mice appeared severely defective in supporting hematopoiesis. The deletion of both Ink4a and Arf genes did not considerably restore the impaired BM microenvironment, leading to a sustained postnatal HSC depletion in Bmi1−/−Ink4a-Arf−/− mice. Our findings unveil a differential role of derepressed Ink4a and Arf on HSCs and their BM microenvironment in Bmi1-deficient mice. Collectively, Bmi1 regulates self-renewing HSCs in both cell-autonomous and nonautonomous manners.
Engraftment of engineered ES cell–derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium
Authors: Kolossov Eugen , Bostani Toktam , Roell Wilhelm , Breitbach Martin , Pillekamp Frank , Nygren Jens M. , Sasse Philipp , Rubenchik Olga , Fries Jochen W. U. , Wenzel Daniela , Geisen Caroline , Xia Ying , Lu Zhongju , Duan Yaqi , Kettenhofen Ralf , Jovinge Stefan , Bloch Wilhelm , Bohlen Heribert , Welz Armin , Hescheler Juergen , Jacobsen Sten Eirik , Fleischmann Bernd K.
Published: September 2006

Cellular cardiomyoplasty is an attractive option for the treatment of severe heart failure. It is, however, still unclear and controversial which is the most promising cell source. Therefore, we investigated and examined the fate and functional impact of bone marrow (BM) cells and embryonic stem cell (ES cell)–derived cardiomyocytes after transplantation into the infarcted mouse heart. This proved particularly challenging for the ES cells, as their enrichment into cardiomyocytes and their long-term engraftment and tumorigenicity are still poorly understood. We generated transgenic ES cells expressing puromycin resistance and enhanced green fluorescent protein cassettes under control of a cardiac-specific promoter. Puromycin selection resulted in a highly purified (>99%) cardiomyocyte population, and the yield of cardiomyocytes increased 6–10-fold because of induction of proliferation on purification. Long-term engraftment (4–5 months) was observed when co-transplanting selected ES cell–derived cardiomyocytes and fibroblasts into the injured heart of syngeneic mice, and no teratoma formation was found (n = 60). Although transplantation of ES cell–derived cardiomyocytes improved heart function, BM cells had no positive effects. Furthermore, no contribution of BM cells to cardiac, endothelial, or smooth muscle neogenesis was detected. Hence, our results demonstrate that ES-based cell therapy is a promising approach for the treatment of impaired myocardial function and provides better results than BM-derived cells.
SEBINI: Software Environment for BIological Network Inference
Authors: Taylor Ronald C. , Shah Anuj , Treatman Charles , Blevins Meridith
Published: September 2006

Summary: The Software Environment for BIological Network Inference (SEBINI) has been created to provide an interactive environment for the deployment and evaluation of algorithms used to reconstruct the structure of biological regulatory and interaction networks. SEBINI can be used to compare and train network inference methods on artificial networks and simulated gene expression perturbation data. It also allows the analysis within the same framework of experimental high-throughput expression data using the suite of (trained) inference methods; hence SEBINI should be useful to software developers wishing to evaluate, compare, refine or combine inference techniques, and to bioinformaticians analyzing experimental data. SEBINI provides a platform that aids in more accurate reconstruction of biological networks, with less effort, in less time.

Availability: A demonstration website is located at . The Java source code and PostgreSQL database schema are available freely for non-commercial use.

Contact:  ronald.taylor@pnl.gov
Dynamic partitioning for hybrid simulation of the bistable HIV-1 transactivation network
Authors: Griffith Mark , Courtney Tod , Peccoud Jean , Sanders William H.
Published: September 2006

Motivation: The stochastic kinetics of a well-mixed chemical system, governed by the chemical Master equation, can be simulated using the exact methods of Gillespie. However, these methods do not scale well as systems become more complex and larger models are built to include reactions with widely varying rates, since the computational burden of simulation increases with the number of reaction events. Continuous models may provide an approximate solution and are computationally less costly, but they fail to capture the stochastic behavior of small populations of macromolecules.

Results: In this article we present a hybrid simulation algorithm that dynamically partitions the system into subsets of continuous and discrete reactions, approximates the continuous reactions deterministically as a system of ordinary differential equations (ODE) and uses a Monte Carlo method for generating discrete reaction events according to a time-dependent propensity. Our approach to partitioning is improved such that we dynamically partition the system of reactions, based on a threshold relative to the distribution of propensities in the discrete subset. We have implemented the hybrid algorithm in an extensible framework, utilizing two rigorous ODE solvers to approximate the continuous reactions, and use an example model to illustrate the accuracy and potential speedup of the algorithm when compared with exact stochastic simulation.

Availability: Software and benchmark models used for this publication can be made available upon request from the authors.

Contact:  tod@crhc.uiuc.edu

Supplementary information: Complete lists of reactions and parameters of the HIV-1 Tat transactivation model, as well as additional results for other benchmark models, are available at
Dyella yeojuensis sp. nov., isolated from greenhouse soil in Korea
Authors: Kim Byung-Yong , Weon Hang-Yeon , Lee Kang-Hyo , Seok Soon-Ja , Kwon Soon-Wo , Go Seung-Joo , Stackebrandt Erko
Published: September 2006

A novel strain, R2A16-10T, was isolated from greenhouse soil in Yeoju, Korea. The taxonomy of strain R2A16-10Twas studied by using polyphasic methods. On the basis of 16S rRNA gene sequence analyses, strain R2A16-10Twas found to be phylogenetically related to type strains ofDyellaspecies (96.7–96.9 %),Frateuria aurantiaDSM 6220T(96.5 %),Fulvimonas soliLMG 19981T(96.3 %) andRhodanobacterspecies (94.9–95.7 %). Strain R2A16-10T, which produced yellow-coloured colonies, was Gram-negative, rod-shaped (0.3–0.4×1.5–3.5 μm) and motile. The predominant fatty acids were 17 : 1 isoω9c(25.5 %), 15 : 0 iso (18.7 %) and 17 : 0 iso (14.6 %), and the major hydroxy fatty acids were 11 : 0 iso 3-OH (5.0 %), 13 : 0 iso 3-OH (3.4 %) and 17 : 0 iso 3-OH (1.0 %). The major isoprenoid quinone was Q-8. The G+C content of the DNA of the type strain was 63.0 mol%. On the basis of the data from this study, strain R2A16-10Trepresents a novel species of the genusDyella, for which the nameDyella yeojuensissp. nov. is proposed. The type strain is R2A16-10T(=KACC 11405T=DSM 17673T).
Loktanella koreensis sp. nov., isolated from sea sand in Korea
Authors: Weon Hang-Yeon , Kim Byung-Yong , Yoo Seung-Hee , Kim Jong-Shik , Kwon Soon-Wo , Go Seung-Joo , Stackebrandt Erko
Published: September 2006

A bacterial strain, GA2-M3T, isolated from a sea-sand sample in Korea, was subjected to polyphasic taxonomic characterization. Cells of strain GA2-M3T were Gram-negative, non-motile, non-spore-forming and short rod- to ovoid-shaped. Comparative 16S rRNA gene sequencing studies confirmed that the bacterium fell within the radiation of the genus Loktanella. Similarity levels between the 16S rRNA gene sequence of strain GA2-M3T and those of type strains of Loktanella species with validly published names were 93.5–96.1 %; highest sequence similarity was with Loktanella rosea. The G+C content of the genomic DNA of strain GA2-M3T was 60.0 mol% and the predominant ubiquinone was Q-10. Major fatty acids were 18 : 1ω7c, 18 : 0 and 18 : 1ω7c 11-methyl. On the basis of the evidence presented, it is proposed that strain GA2-M3T represents a novel species, for which the name Loktanella koreensis sp. nov. is proposed. The type strain is GA2-M3T (=KACC 11519T=DSM 17925T).
Lactobacillus siliginis sp. nov., isolated from wheat sourdough in South Korea
Authors: Aslam Zubair , Im Wan-Taek , Ten Leonid N. , Lee Myung-jin , Kim Kyoung-Ho , Lee Sung-Taik
Published: September 2006

The taxonomic position of two lactic-acid-producing bacterial strains, isolated from wheat sourdough in South Korea, was studied using a polyphasic approach. Phylogenetic analysis on the basis of 16S rRNA gene sequences and biochemical and physiological characteristics indicated these two strains to be members of the genusLactobacillus. They had high 16S rRNA gene sequence similarity (98.5 %) withLactobacillus rossiaeDSM 15814Tand very low (<94.0 %) similarity with any other recognized species of the genusLactobacillus. These two strains (designated M1-212Tand M2-236) were heterofermentative, facultatively anaerobic, Gram-positive, non-spore-forming, non-motile, short rod-shaped bacteria. The optimum growth temperature for these strains was 30 °C (no growth at 15 or 45 °C) and they were able to tolerate 5 % (w/v) NaCl. The G+C content of the genomic DNA of the two strains was 45.5 mol%, within the range of values reported for the genusLactobacillus(32–53 mol%). The peptidoglycan was of the A3α(l-lys–d-glu–l-Ala) type. Physiological, biochemical and genotypic data, as well as results of DNA–DNA hybridization of the genomic DNA with one of the closest phylogenetic relatives,L. rossiaeDSM 15814T, indicated that the strains represent a novel species of the genusLactobacillus, for which the nameLactobacillus siliginissp. nov. is proposed. The type strain is M1-212T(=KCTC 3985T=NBRC 101315T).
Desulfohalobium utahense sp. nov., a moderately halophilic, sulfate-reducing bacterium isolated from Great Salt Lake
Authors: Jakobsen Trine Fredlund , Kjeldsen Kasper Urup , Ingvorsen Kjeld
Published: September 2006

A novel moderately halophilic, sulfate-reducing bacterium, strain EtOH3T, was isolated from anoxic hypersaline (270 g NaCl l−1) sediment of the northern arm of the Great Salt Lake, Utah, USA. Cells of strain EtOH3T were oval to rod-shaped, non-motile, non-sporulating and stained Gram-negative. The strain required sodium and magnesium ions for growth and grew at salinities of up to 240 g NaCl l−1 and 121 g MgCl2.6H2O l−1. The optimum NaCl concentration was 80–100 g l−1. Strain EtOH3T grew at temperatures ranging from 15 to 44 °C (optimum 37 °C). The pH range for growth was 6.5–8.3 (optimum around pH 6.8). Only sulfate and thiosulfate served as electron acceptors for a broad range of electron donors including various short-chain fatty acids and primary (C1–5) alcohols, amino acids, H2/acetate and H2/yeast extract. The G+C content of the genomic DNA was 51.4 mol%. Phylogenetic analysis of dsrAB [genes encoding the major subunits of dissimilatory (bi)sulfite reductase] and 16S rRNA gene sequence data placed strain EtOH3T within the deltaproteobacterial family Desulfohalobiaceae. Strain EtOH3T shared 76 and 91 % dsrAB and 16S rRNA gene sequence similarity, respectively, with the type strain of the phylogenetically most closely related species with a validly published name, Desulfohalobium retbaense DSM 5692T. High 16S rRNA gene sequence similarity (~97 %) was shared with the recently described strain ‘Desulfovermiculus halophilus’ VKM B-2364. Strain EtOH3T, however, clearly differed from this strain in both genomic G+C content and in several of its phenotypic properties. On the basis of phenotypic and genotypic characteristics, the novel species Desulfohalobium utahense sp. nov. is proposed, with strain EtOH3T (=VKM B-2384T=DSM 17720T) as the type strain.
Emendation of the genus Flammeovirga and Flammeovirga aprica with the proposal of Flammeovirga arenaria nom. rev., comb. nov. and Flammeovirga yaeyamensis sp. nov.
Authors: Takahashi Mai , Suzuki Ken-ichiro , Nakagawa Yasuyoshi
Published: September 2006

The taxonomic positions of five bacterial strains isolated from the Yaeyama Islands of Japan and ‘Microscilla arenaria’ NBRC 15982 were determined using a polyphasic taxonomic approach. 16S rRNA gene sequence analyses placed all of the strains close to the genus Flammeovirga. DNA–DNA hybridization studies, biochemical and physiological characterizations and chemotaxonomic analyses suggested that ‘M. arenaria’ NBRC 15982 and the five novel isolates represented two separate species of the genus Flammeovirga. Emendation of the genus Flammeovirga Nakagawa et al. 1997 and the species Flammeovirga aprica (Reichenbach 1989) Nakagawa et al. 1997 is proposed. In addition, ‘Microscilla arenaria’ Lewin 1969 is proposed as Flammeovirga arenaria nom. rev., comb. nov. (with the type strain NBRC 15982T=CIP 109101T) and the novel isolates are proposed as Flammeovirga yaeyamensis sp. nov. (type strain IR25-3T=NBRC 100898T=CIP 109099T).