bluuebunny/crossref_metadata_2025 huggingface dataset:
Organoamido- and Aryloxo-lanthanoids. III. Preparation and X-Ray Structure of Bis(μ-3,5-dimethylpyrazolato-N:N′)bis(μ-tetrahydrofuran-O)-bis[bis(η2-3,5-dimethylpyrazolato-N,N')neodymium(III)]
Authors: Deacon GB , Gatehouse BM , Nickel S , Platts SN
Published: September 2010

Reaction of neodymium metal with bis ( pentafluorophenyl )mercury and pyrazole ( Hpz ) or 3,5-dimethylpyrazole ( Hdmpz ) in tetrahydrofuran ( thf ) yields Nd ( pz )3 or [ Nd ( dmpz )3( thf )]2. X-Ray crystallography has shown that [Nd (dmpz )3( thf )]2 [triclinic, space group Pī (No. 2), a 11.070(4), b 11.364(3), c 10.867(2)Ǻ, α 103.00(1), β 120.78(3), γ 97.68(2)°, R 0.0235, Rw 0.0247 for 5575 observed reflections] has a novel centrosymmetric dimeric structure. Each neodymium is eight-coordinate (4,4 bicapped trigonal prism) with two terminal chelating dmpz ligands [ Nd -N 2.400(2), 2.413(3), 2.422(3), 2.426(3)Ǻ], two bridging dmpz ligands [ Nd -N 2.509(2),
2.511(2)Ǻ], and, unexpectedly, two bridging tetrahydrofuran ligands [ Nd -O 2.792(2),
2.757(2)Ǻ].
The Palladium-Mediated Cross Coupling of Bromotropolones With Organostannanes or Arylboronic Acids: Applications to the Synthesis of Natural Products and Natural Product Analogs
Authors: Banwell MG , Cameron JM , Collis MP , Crisp GT , Gable RW , Hamel E , Lambert JN , Mackay MF , Reum ME , Scoble JA
Published: September 2010

The bromotropolones (4), (5) and (10) undergo palladium-mediated cross coupling with a wide range of organostannanes to produce alkenyl -, alkyl- and aryl-substituted tropolones . The methodology has been applied to the synthesis of the monoterpenes β- dolabrin (11),β- thujaplicin (12), 4-isopropyl-7-methoxytropolone (13) and β- thujaplicinol (14). Cross coupling of bromotropolones (4), (5) and (10) with various aryltrimethylstannanes or arylboronic acids has permitted the preparation of the bicyclic colchicine analogues (30)-(43) which have been tested for tubulin -binding activity. The X-ray crystal structure of the most active of these systems, compound (38), is reported.
Molecular Cocrystals of Carboxylic Acids.II. The Crystal Structure of the 1 : 2 Adduct of Phenoxyacetic Acid With 3,5-Dinitrobenzoic Acid
Authors: Lynch DE , Smith G , Byriel KA , Kennard CHL
Published: September 2010

The 1 : 2 molecular adduct between phenoxyacetic acid and 3,5-dinitrobenzoic acid, with formula [(C6H5OCH2COOH)2{3,5-(NO2)2C6H3COOH}4(H2O)2], has been prepared and its structure determined by X-ray diffraction. Crystals are triclinic, space group Pī with two complex units in a cell with dimensions a 7.202(2), b 18.519(5), c 20.924(6)Ǻ, α 66.33(3),β 86.04(2),γ 89.32(2)°. The molecular repeating unit comprises two phenoxyacetic acid molecules [forming hydrogen-bonded cyclic dimers (O̷O, 2.71, 2.74 Ǻ)], four 3,5- dinitrobenzoic acid molecules [giving two unusual one-bond hydrogen bonds (O…O, 2.59, 2.64Ǻ)] and two water molecules. The waters are intimately involved in a hydrogen-bonding network with carboxylic acid oxygens.
Lanthanide Ion Complexes of Calixarenes. VII. Bimetallic Lanthanide Complexes of p-t-Butylcalix[8]arene From Dimethyl Sulfoxide Solutions
Authors: Harrowfield JM , Ogden MI , White AH
Published: September 2010

Reaction of Ln (ClO4)3.x dmso ( dmso denotes dimethyl sulfoxide ) with a warm p-t- butylcalix [8] arene (L) slurry in acetone/ dmso yields crystalline 2:1 Ln/ligand adducts, characterized as dmso olvates and established to be [Ln2(L-6H)( dmso )5].~2dmso by single- crystal X-ray studies at c. 295 K for Ln = La, Eu , Tm and Lu. All complexes are isomorphous , orthorhombic, Pcnb, a ≈ 34, b ≈ 23, c ≈ 14 Ǻ, Z 4, with a similar complex molecule in each case, one half comprising the asymmetric unit; the second half is generated by a crystallographic twofold axis. The two lanthanide atoms are encompassed by the macrocycle and are eight coordinate, involving phenolic and dmso O-donor atoms, five of the former (two bridging) and three of the latter (one bridging). The array closely resembles that found in analogous dmf solvent adducts: the bridging dmso lies on the crystallographic twofold axis through the complex, its peripheral atoms being modelled by disorder.
Directed ortho Metalation Studies on Podocarpic Acid Derivatives: Advantageous Use of a LICKOR Base
Authors: Cambie RC , Higgs PI , Lee KC , Metzler MR , Rutledge PS , Stevenson RJ , Woodgate PD
Published: September 2010

Methyl 13-(N,N- diethylcarbamoyl )-12-methoxypodocarpa-8,11,13-trien-19-oate (2), 13-(N,N- diethylcarbamoyl )-12,19-dimethoxypodocarpa-8,11,13-triene (8) and N,N-diethyl-2-methoxy-4,5-dimethylbenzamide (15) were prepared for studies involving lithiation directed ortho to the tertiary amide group, in which the use of a LICKOR base was advantageous. Some dynamic features of the n.m.r. spectra of the amides are discussed. Oxazoline derivatives of both tile monocyclic and diterpenoid compounds were synthesized.
The Synthesis of Bisanthraquinones Joined by Polyether Linkages
Authors: Russell RA , Longmore RW
Published: September 2010

Derivatives of quinizarin linked by polyether chains have been prepared by the annelation of bis (quinone monoacetals) with the anions of substituted 3-cyanophthalides.
Steric Effects of the Spin State of Iron(II) in Complexes of Substituted Bipyridine Derivatives
Authors: Onggo D , Goodwin HA
Published: September 2010

Iron(II) and nickel(II) complexes of dimethyl 2,2′-bipyridine-3,3′-dicarboxylate (dmbc), 1,1′-biisoquinoline (biq), 6,6′-dimethyl-2,2′-bipyridine (dmbpy) and 4,4′6,6′-tetramethyl-2,2′- bipyridine (tmbpy) have been prepared. [FeN6]2+ derivatives of dmbc and biq were isolated as solid salts. These show anomalous temperature dependence of their magnetism and Mossbauer spectra which has been interpreted in terms of a thermally induced singlet (1A1) ↔ quintet (5T2) transition. The transition is also observed for [Fe(biq)3][BF4]2 in solution and has been analysed in terms of a thermal equilibrium involving the two spin states. Electronic spectral data for the [NiN6]2+ derivatives indicate values for the field strength of these ligands which are consistent with the appearance of the transition in the iron(II) species. Both dmbpy and tmbpy yield only bis(ligand) complexes with either iron(II) or nickel(II). Infrared spectral data suggest that in these complexes the associated perchlorate or fluoroborate anions are coordinated, which leads to distorted six-coordinate structures. A similar iron(II) complex was isolated with 2,9-dimethyl-1,10-phenanthroline.
The Structure and Function of Estrogens. XI. Synthesis of (±)-7(8→11α)abeo-Estradiol and Its 9,11-Didehydro Derivative
Authors: Collins DJ , Fallon GD , Skene CE
Published: September 2010

Two approaches to the synthesis of (�)-7(8→11α)abeo-estra-1,3,5(10)-triene-3,17 β- diol (2a) from (�)-1 β-t-butoxy-7a β-methy1-2,3,3a α,6,7,7a-hexahydro-1H-inden-5(4H)-one (11) were studied. A pathway involving 6-alkylation of (11) with 2-(3′-methoxyphenyl)ethyl halides or sulfonate esters was unsuccessful, but conjugate addition of 3-methoxybenzyl nucleophiles with (�)-1β-t-butoxy-7a β-methyl-6-methylene-2,3,3a,6,7,7a-hexahydro-1H-inden-5(4H)-one (18), prepared from (11), led to ( �)-1β-t-butoxy-6 α-[2′-(3″-methoxyphenyl)ethy1]-7a β α,6,7,7a-hexahydro-1H-inden-5(4H-one (10a). Acid-catalysed cyclization of (10a) afforded (�)-17β-t-butoxy-3-methoxy-7(8 →11)abeo-estra-l,3,5(10),9(11)-tetraene (29) which upon lithium/ammonia reduction in the presence of diphenylmethane gave ( �)-17 β- t-butoxy-3-methoxy-7(8 →11α)abeo-estra,1,3,5(10)- triene (31). Deprotection of (31) and (29) afforded (�)-7(8 →11 α)abeo-estra-1,3,5(10)-triene-3,17 β- diol (2a) and (�)-7(8 →1l)abeo-estra-1,3,5(10),9(11)-tetraene-3,17β-diol (32), respectively. Alternatively, reaction of (�)-1β-t-butoxy-7a β-methyl-6-methylene-2,3,3a α,6,7,7a-hexahydro-1H-inden-5(4H)-one (18) with 3-methoxybenzyl phenyl sulfoxide (23a) gave (1RS,3′SR,2RS,-3a′SR,7a′SR)-3′-t-butoxy-2-(3″-methoxyphenyl)-3a′-methyl-2′,3′,3a′,4′7′,7a′-hexahydrospiro- [cyclopropane-1,5′-[5H]inden ]-6′(1′H)-one (26), reductive cleavage of which with lithium/ammonia afforded (10a). The relative stereochemistries of (31) and of the spiro cyclopropyl ketone intermediate (26) were established unambiguously by X-ray crystallography.
The Role of the Substituent Pattern in Determining Selectivity in the Preparation of Tricarbonyl(η5-cyclohexadienyl)iron(1+) Salts by Acid-Catalyzed Demethoxylation
Authors: Stephenson GR , Owen DA , Finch H , Swanson S
Published: September 2010

The factors that determine the selectivity of the acid-catalysed dealkoxylation of unsymmetrically substituted tricarbonyl(η4-alkoxycyclohexa-1,3-diene)iron(0) complexes have been investigated. Regioselective demethoxylation of complexes with a variety of substitution patterns has indicated that the selectivity arises from differences in the stabilization of the reaction intermediates and transition states by the diene substituents on the π-bound ligand. The observed regioisomers correspond to the product of the most stabilized intermediate pathway, rather than the product of minimum rearrangement. The reactions have been shown to proceed under kinetic control.
Synthesis and Explosive Properties of Benzotriazoles
Authors: Flippenanderson JL , Flippenanderson JL , Gilardi RD , Gilardi RD , Pitt AM , Pitt AM , Wilson WS , Wilson WS
Published: September 2010

Treatment of nitro-substituted 2-aminodiphenylamines in acetic acid with either nitric acid or nitrous acid yielded nitro-substituted 1-phenylbenzotriazoles, which may be further nitrated with nitric or mixed acid. These materials have been examined as potential energetic materials, with particular reference to their densities, calculated explosive properties and sensitiveness, especially impact sensitivity.
Molecular Cocrystals of Carboxylic Acids. VI. The Crystal Structures of the Adducts of Triphenylphosphine Oxide With Benzene-1,3,5-tricarboxylic Acid and (2,4,5-Trichlorophenoxy)acetic Acid
Authors: Lynch DE , Smith G , Byriel KA , Kennard CHL
Published: September 2010

The crystal structures of the triphenylphosphine oxide adducts with benzene-1,3,5-tricarboxylic acid (2 : 1) (1) and (2,4,5-trichlorophenoxy)acetic acid (1 : 1) (2) have been determined and refined to residuals R 0.085 and 0.032 for 2531 and 3348 observed reflections, respectively. Both are triclinic with two heteromeric units in cells of dimensions a 8.66(1), b 13-58(2), c 18.17(3) �, α 99.12(8), β 101.45(8), γ 107.54(7) � for (1), and a 9.062(6), b 9.726(7), c 15.19(1) �, α
103.80(4), , β 104.94(4), γ 96.42(5)� for (2). In each structure, strong single directed hydrogen bonds are found between the protons of the carboxylic acid donor groups and the triphenylphosphhine oxide acceptors. With (1), only two of the carboxylic acid groups are heteromerically associated [O . . .O, 2.5O(1), 2.54(1) �] while the third forms a single intermolecular association [2.61(1) �]. In the case of (2), a single acid-oxide association is found [O...O, 2.540(3) �]. The (2,4,5-trich1orophenoxy)acetic acid molecule has an antiplanar conformation which contrasts with the synplanar conformation of the parent acid.
A Simple, Accurate Model for Porphyrin Ring-Current Shifts
Authors: Cross KJ , Crossley MJ
Published: September 2010

A computationally simple, but accurate, model for porphyrin ring-current shifts is presented and calibrated by using X-ray and n.m.r. data from cytochrome c, cytochrome C551, cytochrome b5, and pyridine and picoline complexes of zinc porphyrin . The model involves a multipole expansion in terms of Legendre polynomials of the cosine of the polar angle and reciprocal powers of the distance between the centre of the porphyrin ring and the atom of interest. The multipole model offers a simple analytical expression for the ring-current shift in contrast to the complex expressions derived from the Johnson-Bovey and Haigh-Mallion models. The model was tested with a series of capped porphyrins and gave capto-porphyrin separations in excellent agreement with the X-ray structures at low temperature. Excellent agreement is also observed between calculated and observed ring-current shifts, even for protons in close proximity to the porphyrin ring.
Nitrones and Oxaziridines. XLIII. Synthesis of an Indol-7-yl-Substituted 1-Pyrroline 1-Oxide and Related Compounds
Authors: Black DS , Debdas RB , Kumar N
Published: September 2010

The 1-pyrroline 1-oxide (8) which contains an indol-7-yl substituent attached to the 2-position has been synthesized by reductive cyclization of the related γ -nitro ketone . The corresponding 1-pyrroline (9) has also been isolated as the result of non-selective reduction. A comparison of the indol-7-yl nitrone (8) is made with related indol-3-yl nitrones described earlier.
Synthesis of Winterin From Podocarpic Acid
Authors: Bendall JG , Cambie RC , Grimsdale AC , Rutledge PS , Woodgate PD
Published: September 2010

Ozonolysis of a hydroquinone derived from podocarpic acid (1) gave the biologically active natural product winterin (11). Treatment of the quinone (12) with ozone gave a ring-contracted spiro furanone, the mechanism of formation of which is proposed.
Non-Equilibrium Reactions of α-Phase PrOx With O2
Authors: Kang ZC , Zhang J , Eyring L
Published: September 2010

In this paper we use electron diffraction and high-resolution imaging techniques to study the structural consequences of rapid cooling, to room temperature, of fine particles of praseodymium oxide prepared as the disordered α-phase in the composition range from PrO1.78 to PrO1.83 These experiments reveal that particles of the disordered fluorite phase, prepared at higher temperatures, pass through many steps of order as they cool and oxidize to ordered intermediate structures in their near-surface regions. The entities that bring about this transformation are condensed vacant oxygen sites that segregate on {220} planes and finally order to give members of the even-n homologous series PrnO2n-2. The unit cells for new members of the series with n assumed to be 16 are reported.
Structural Study of Curvularin, a Cell Division Inhibitor
Authors: Ghisalberti EL , Hockless DCR , Rowland CY , White AH
Published: September 2010

The structure of the fungal metabolite curvularin, a spindle poison, has been determined by X-ray crystallographic methods. The conformation of the macrocyclic lactone ring in the solid state and that deduced from n.m.r. studies in solution are similar.
Approaches to the Synthesis of Retronecine From Some Pyrrolidine Precursors
Authors: Clare BW , Ferro V , Skelton BW , Stick RV , White AH
Published: September 2010

Procedures are described for the attempted conversion of the pyrrolidine (2) into a bicyclic system that would ultimately lead to retronecine (3). The only molecule to be isolated from these attempts was the epimeric ketone (6), and AM1 and MM2 calculations were used to probe this apparently favoured isomerization. Alternative procedures were then investigated that sought to convert the pyrrolidine (1) into precursors to retronecine, and notable successes were obtained with the addition of the amine (21) to both nitroethene and ethyl 2-diethylphosphonoacrylate. However, not only were these precursors resistant to further transformations into retronecine , but also the problem of epimerization again arose. Consequently, AM1 calculations were again employed, and an X-ray structure determination of ethyl (7R,8R)-7-benzyloxy-1-benzyloxymethyl-5,6,7,8-tetrahydro-3H-pyrrolizine-2-carboxylate (39) is reported. Attempts to convert (39) into a diastereoisomer of retronecine were unsuccessful.
Tropical Marine Algae. IX. A New Sesquiterpenoid Metabolite From the Red Alga Laurencia marianensis
Authors: Denys R , Coll JC , Bowden BF
Published: September 2010

An investigation of the natural products chemistry of the red alga Laurencia marianensis Yamada, a species whose chemistry has not previously been described in the literature, yielded the new metabolite 1-[(3′S*,3a′lR*,4′R*,7′S*,7a′S*)-7′-bromo-7a′-methyl-3′-(1′-methylethyl)octahydro-1′H-inden-4′-yl] ethanone (1) and the known metabolites deoxyprepacifenol (2) and pacifenol (3). The full n.m.r. characterization of (2) and (3) is reported for the first time.
The Chemistry of Pyrrolic Compounds. LXVIII. 13'- and 15'-Methyl Analogs of Deoxophylloerythroetioporphyrin (dpep)
Authors: Bong ICC , Clezy PS , Fookes CJR , Prashar JK , Salek A
Published: September 2010

A new synthesis of the 13′-methyl (1a) analogue of dpep is described commencing with the methylation of phylloerythroetioporphyrin (1d) with subsequent reduction of the derived tertiary alcohol. The availability of this synthetic material has allowed the presence of this petroporphyrin as its nickel complex to be confirmed in the Julia Creek oil shales. The presence of an isomer of this petroporphyrin has been noted in the same deposit, and the structure of this novel fossil porphyrin has been confirmed as the 15′-methyl analogue (1b) of dpep by a synthesis commencing from the 15′-oxoporphyrin (1e). In addition, the 15′- and 13′-methyl analogues of dpep have been synthesized by cylization of appropriately substituted propenyl- and isopropenyl-porphyrins respectively. The origin of these two petroporphyrins is discussed.
Spongiaquinone Revisited: Structural and Stereochemical Studies on Marine Sesquiterpene/Quinones From a Southern Australian Marine Sponge, Spongia sp.
Authors: Capon RJ , Groves DR , Urban S , Watson RG
Published: September 2010

A chemical investigation of a large purple sponge, Spongia sp., from the Great Australian Bight, resulted in the isolation of a new sesquiterpene/quinone (8), together with the known compounds dehydrocyclospongiaquinone-1 (4) and spongiaquinone (2). The last compound was also isolated as the potassium salt (9), this being the first recorded account of a naturally occurring marine sesquiterpene/quinone salt. The structure for (8) was assigned by detailed spectroscopic analysis. A re-investigation into the stereostructure of spongiaquinone (2) resulted in the first unambiguous assignment of absolute stereochemistry, and uncovered the peculiar chiroptical properties of spongiaquinone (2) and its potassium salt (9).
Chiral Sulfur Compounds. XXI. Addition of Azide Ion to β-Aryl-α-phenylsulfinylacrylates
Authors: Dong Z , Hellmund KA , Pyne SG
Published: September 2010

The reaction of methyl β-aryl-α- phenylsulfinylacrylates (1) with sodium azide /acetic acid gives triazoles (6) while the reaction of (1) with sodium azide /hydrochloric acid gives β-azido esters (7a,b). Reaction of (7a) with 1,8-diazabicyclo[5.4.0]undec-7-ene, and (7b) with triethylamine gave the corresponding triazoles (6a) and (6b), respectively. Thus the formation of triazoles from the reaction of acrylates with azide ion most likely involves Michael addition of azide ion followed by cyclization of an incipient β-azido α-anion.
3-Monoterpenyl 2,4-Dioxygenated Quinoline Alkaloids From the Aerial Parts of Eriostemon australasius subsp. banksii (Rutaceae)
Authors: Dacunha EVL , Armstrong JA , Gray AI , Hockless DCR , Waterman PG , White AH
Published: September 2010

An extract of the aerial parts of Eriostemon australasius Pers.subsp. banksii (A. Cunn. ex Endl .) P.G. Wilson ( Rutaceae ), collected from the Cape York Peninsula, has yielded four novel secondary metabolites. These were identified, by spectroscopic methods, as methyl (E)-4-(3′-methylbut-2′-enyloxy) cinnamate, cis-erioaustralasine [{rel}-1-acetoxymethyl-4,8′-epoxy-3-(1′β,2′β-epoxy-3′β,4′β-para-menth-3′-yl)quinolin-2-one], trans- erioaustralasine [{rel}-1-acetoxymethyl-4,8′-epoxy-3-(1′β,2′β-epoxy-3′β,4′α-para-menth-3′-yl)quinolin-2-one] and furoerioaustralasine [{rel}-2,2′β:4,8′-diepoxy-3-(1′β-hydroxy-3′α,4′α-para-menth-3′-yl) quinoline ]. The structure of cis-erioaustralasine was confirmed by X-ray crystallographic studies. The taxonomic significance of the occurrence of these alkaloids in E. australasius is discussed.
The Photochemistry of Isobenzofuran. I. Structure of the Dimers Resulting From Ultraviolet Irradiation of Isobenzofuran in Acetone and Ether Solution
Authors: Warrener RN , Pitt IG , Russell RA
Published: September 2010

Irradiation of isobenzofuran (1) in acetone solution yields a symmetrical [π8s+π8s] dimer (24) involving bonding at the peri -position of the furan moiety in each molecule. The anti-stereochemistry of this dimer was established by a novel application of lanthanide induced shift spectroscopy. In contrast, irradiation of isobenzofuran (1) in ether solution yielded the unsymmetrical dimer (34) as the major product, together with lesser amounts of the symmetrical dimer (24), and small amounts of a new dimer (50) resulting from [π8s+π4s] cycloaddition , where the 8π system of the isobenzofuran of one molecule reacts with the carbocyclic 4π diene of the other. The structure of the unsymmetrical dimer (34) was confirmed by synthesis. No evidence for the Dewar form (7e) of isobenzofuran could be obtained in these reactions conducted at -60° and monitored by 1H n.m.r. spectroscopy. However, the small, but persistent, production of o-phthalaldehyde may implicate an intermediate derived from (7e).
Rin -Opening of Acetal III (8,13/13,17-Diepoxy-14,15-dinorlabdane) and the Synthesis of Potential Odorants Derived From Manool
Authors: Grant PK , Hanton LR , Lynch GP , Robinson WT , Wong G
Published: September 2010

A novel ring opening of the acetal III (2) (8,13:13,17-diepoxy-14,15-dinorlabdane) with boron trifluoride/acetic anhydride led to the synthesis of acetals (16), (18)-(20) and (25)-(27) functionalized at C 12. The attempted ring opening of the hydroxy acetal (28) produced the dimer (32). Also prepared were the cyclic ethers (36), (38) and (39), none of which, however, exhibited significant ambergris-type odours.
Structural Systematics of Rare Earth Complexes. IV. Structural Characterization of Lanthanoid(III) Picrate Hydrates: the Quasi-Undecahydrate of Samarium(III) Picrate
Authors: Harrowfield JM , Skelton BW , White AH
Published: September 2010

The structural characterization of a new quasi- undecahydrate of samarium(III) picrate is described. [ Sm ( pic )2(OH2)6]( pic ).43/4H2O is monoclinic, C 2/c, a 39.96(1), b 7.951(2), c 24.233(9) Ǻ, β 110.92(2)°, Z = 8, temperature c.295 K; R was 0.047 for 5010 'observed' diffractometer reflections. Like the cations of Part I, the present has two picrate and six aqua ligands; although the general stereochemistry is similar, the picrate ligands are both clearly unidentate, unlike previous arrays wherein one behaves in a quasi- bidentate mode utilizing an ortho-nitro oxygen atom.
All About 3,4,6-Tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucosyl Trichloroacetimidate
Authors: Best WM , Dunlop RW , Stick RV , White ST
Published: September 2010

Treatment of 1,3,4,6-tetra-O-acetyl-2-(o-carboxybenzoylamino )-2-deoxy-β-D-glucose with ethyl chloroformate , followed by workup and treatment with methanol, did not give 1,3,4,6-tetra O-acetyl-2-deoxy-2-phthalimido-β-D-glucose as reported in the literature, but rather the methyl ester 1,3,4,6-tetra-O-acetyl-2-deoxy-2-(o- methoxycarbonylbenzoylamino )-β-D-glucose. The formation of this methyl ester is believed to proceed via 1,3,4,6-tetra-O-acetyl-2-deoxy-2- [(3′-oxo-1′,3′-dihydroisobenzofuran-1′-ylidene)amino]-β-D-glucose which was also formed from the amido carboxylic acid by treatment with dicyclohexylcarbodiimide . Optimal procedures are given for the preparation of the title compound 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-D-glucosyl trichloroacetimidate.
Synthesis and N.M.R. Studies of New Unsymmetrically Substituted Ditertiary Phosphines
Authors: Bowmaker GA , Williams JP
Published: September 2010

The synthesis and characterization of rac- and meso-(E)-1,2-C2H2( PMePh )2 (1), 1,2-C6H4( PMePh )(PPh2)(2),1,2-C6H4( PBuPh )(PPh2)(3) and 1,2-C6H4(Pme2)(PPh2) (4) are reported. Reaction of (1) with MeI (1:2) gives [(E)-1,2-C2H2(Pme2Ph)2]I2 (5). The compound [(E)-1,2-C2H2(PPh2)(PmePh2)]I (6) was synthesized from (E)-1,2-C2H2(PPh2)2 and MeI (1:1). 1H n.m.r. spectra are reported for (2), (3), (5) and 6. 31P n.m.r. spectra are reported for (1)-(3), (5), (6) and [(E)-1,2-C2H2(PmePh2)2]I2 (7). 2J(PV,H) and trans 3J(H,H) coupling were observed in the 1H n.m.r. spectra of (6). Substitution of one Ph group for one Me group at phosphorus in a ditertiary phosphine produces a change in chemical shift of 19.5 and 21.8 ppm for (E)-CH=CH and 1,2-C6H4 interphosphorus linkages respectively. The interphosphorus linkage in a ditertiary phosphine produces large 3J(P,P) coupling constants (c. 155 Hz), and an increase in screening of the phosphorus nuclei (c. 10 ppm ).
Selective O-Methyloxime Formation From 6-Methoxy-2-[(1'-methyl-2',5'-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one
Authors: Collins DJ , Fallon GD , Skene CE
Published: September 2010

Reaction of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (4a) with 1 or 2 moles of O- methylhydroxylamine hydrochloride in pyridine gave (1′SR,2RS)-6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (E)-2′-O-methyloxime (5a), or the corresponding 2′,5′-bis(O-methyloxime ) (6), respectively. A minor product from the formation of the bis (O- methyloxime ) (6) was the (Z) isomer (5b) of the mono(O- methyloxime ) (5a); the structure and stereochemistry of (5a) and (5b) were established by X-ray crystallography. Reduction of the keto bis (O-methyloxime ) (6) with 0.25 mole of lithium aluminium hydride gave a diastereomeric mixture of the corresponding alcohols (7a), of which the major isomer was characterized by ester formation. The bis (O-methyloxime ) (6) could be hydrolysed to the parent triketone (4a), but it resisted deprotection with cetyltrimethylammonium permanganate. Reaction of the triketone (4a) with 1 mole of 4-anisidine in the presence of 4-toluenesulfonic acid resulted in retro Michael cleavage with formation of 3-(4′-methoxyphenyl)amino-2-methylcyclopent-2-en-1-one (1).
Factors Influencing the Measurement of Calcium Concentrations in Biological Fluids by 19F N.M.R. Spectroscopy
Authors: Mendz GL
Published: September 2010

Fluorinated derivatives of fluorescent calcium probes have been recently used to measure free calcium concentrations in biological fluids by 19F n.m.r. spectroscopy. To measure calcium levels a method utilizes the change in chemical shift experienced by the fluorine resonance of the calcium chelator 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N′,N′- tetraacetic acid upon complexation of cations. The procedure assumes that (A) the fluorinated probe is in equilibrium between the calcium complex and the free acid form; (B) the chemical exchange between different sites has similar effects on the intensities of the observable resonances; and (c) the presence of macromolecules affects equally the intensities of the resonances arising from different complexes. Experiments designed to test these assumptions were carried out in plasma and in model systems containing mixtures of cations and macromolecules. The results indicated that in biological fluids the calcium probe is involved in a multisite equilibrium in which 'invisible' (very broad) peaks affect the equilibrium intensities of the 'observable' peaks. Binding to macromolecules affected differently the intensities of the resonances arising from different complexes in the spectrum of the chelator , and influenced significantly the calculated free calcium concentrations.
Structural Characterization of a Calix[4]arene Constrained to a 1,3-Alternate Conformation by Polyether Bridging
Authors: Asfari Z , Harrowfield JM , Sobolev AN , Vicens J
Published: September 2010

Despite evidence of coordinative interactions with alkali metal picrates in solution, attempts to crystallize Li+, Na+, K+, Rb+ or Cs+ complexes of a 'doubly crowned' calix [4] arene (obtained by reaction of tetraethylene glycol ditosylate with p-t- butylcalix [4] arene ) have resulted only in the deposition of crystals of the free ligand . A room-temperature single-crystal X-ray study has shown the crystals to be hexagonal, space group P6422, a (= b) 17.092(5), c 20.147(7) Ǻ, V 5097(5) Ǻ3, Z 3, conventional R (on |F|) 0.082 for 1397 'observed' reflections [I > 3σ(I)]. The highly symmetrical oblate-globular shape of this doublecrowncalix allows the enclosure of an extended narrow cavity possibly better suited to the binding of two small metal ions rather than one large.
The Crystal Structure of Tris(2,2'-bipyridine)ruthenium(II) Perchlorate
Authors: Harrowfield JM , Sobolev AN
Published: September 2010

[Ru ( bpy )3] (ClO4)2 ( bpy = 2,2′-bipyridine) crystallizes from aqueous solution in an anhydrous form as deep red tablets. A single-crystal X-ray study at 293(2) K has shown the material to be monoclinic, space group C 2/c, a 17.633(4), b 10.761(2), c 15.924(4) Ǻ, β 90.77(2)°, V 3021(1) Ǻ3, Z 4; R was 0.034 for 2405 'observed' [I > 3σ(I)] reflections. The [ Ru ( bpy )3]2+ cation in the perchlorate salt shows very closely similar bond length [ Ru -N, 2.056(3)- 2.060(3)Ǻ], angle and torsion characteristics to those of the known hexafluorophosphate salt, though the two salts are not isomorphous.
Ring Opening and Rearrangement of a Nitro-Capped Cobalt(III) Cage Complex With an N3S3 Donor Set
Authors: Osvath P , Sargeson AM
Published: September 2010

Treatment of the N3S3 donor cage complex [Co(NO2-capten)]3+ (1-methyl-8-nitro-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]icosanecobalt(III)) with excess base leads to deprotonation of a secondary coordinated amine group, followed by loss of a methylene unit from the cap by a retro-Mannich type reaction. Subsequent intermolecular hydride transfer gives a novel oxidized and partly delocalized macrocyclic complexed carbanion (13-(4-amino-2-thiabutyl)-13-methyl-6-nitro-1,11-dithia-4,8-diazacyclotetradec-4-enato(6)cobalt(III)) that is stabilized by deprotonation, and which remains deprotonated even in strong acid.
Derivatives of 4-(Aminomethyl)pyrrole-3-carboxylic Acid
Authors: Arnold DP , Brown RFC , Nitschinsk LJ , Perlmutter P , Tope HK
Published: September 2010

Methyl and ethyl esters of 4-( aminomethyl )pyrrole-3-carboxylic acid were made through pyrrole synthesis with tosylmethyl isocyanide , but cyclization to a bicyclic lactam (1) was not achieved.
Molecular Cocrystals of Carboxylic Acids. XV. Preparation and Characterization of Heterocyclic Base Adducts With a Series of Carboxylic Acids, and the Crystal Structures of the Adducts of 2-Aminopyrimidine With 2,6-Dihydroxybenzoic Acid, 4-Aminobenzoic Acid, Phenoxyacetic Acid, (2,4-Dichlorophenoxy)acetic Acid, (3,4-Dichlorophenoxy)-acetic Acid and Salicylic Acid, and 2-Aminopyridine With 2,6-Dihydroxybenzoic Acid
Authors: Lynch DE , Smith G , Freney D , Byriel KA , Kennard CHL
Published: September 2010

The molecular adducts of the heterocyclic base 2-aminopyrimidine with the aromatic and aromatic aliphatic carboxylic acids salicylic acid, 2,6-dihydroxybenzoic acid and 4-aminobenzoic acid, phenoxyacetic acid, (2,4-dichlorophenoxy)acetic acid, and (3,4-dichlorophenoxy)acetic acid have been prepared, and their interactive modes characterized by single-crystal X-ray diffraction methods. In addition, the complexes with (4-chlorophenoxy)acetic acid, (2,3-dichlorophenoxy)acetic acid, (4-chloro-2-methylphenoxy)acetic acid and (2,4,5- trichlorophenoxy)acetic acid have been characterized by analytical methods, including infrared spectroscopy. Except for the phenoxyacetic acid adduct (2:1), all form 1:1 molecular associations in which the carboxylic acid shows a variable tendency to protonate the hetero nitrogen of the base. The 1:1 complex of 2-aminopyridine with 2,6-dihydroxybenzoic acid has also been characterized by single-crystal X-ray diffraction.
New Tambjamine Alkaloids From the Marine Bryozoan Bugula dentata
Authors: Blackman AJ , Li CP
Published: September 2010

Four new and two previously known tambjamine alkaloids have been isolated from the organic extracts of the bryozoan Bugula dentata. The structures of the metabolites were elucidated by interpretation of their spectral data.
Electrophoretically Deposited Titanium Dioxide Thin Films for Photovoltaic Cells
Authors: Matthews D , Kay A , Gratzel M
Published: September 2010

A new technique for forming porous thin layers of nano -colloidal titanium dioxide on electronically conducting glass was developed. This technique uses constant-current electrophoretic deposition from a dispersion of Degussa P-25 titanium dioxide in 2-methoxyethanol followed by air-drying and annealing. Dye-sensitized TiO2 photovoltaic cells constructed with these films gave current-voltage characteristics comparable with those of films produced by other techniques. A 30 cm2 prototype photovoltaic cell was constructed with electrophoretically deposited TiO2, and tested. Measurement of the dark current and photocurrent enabled the calculation of the light current, and the effect of both the dark current and the series resistance on the cell performance was demonstrated.
Bonding in Small Diatomic Molecules: an Analysis Using Simplified Group Function (SGF) Theory
Authors: Shapley WA , Schipper PE
Published: September 2010

Simplified group function (SGF) theory is used to analyse the energetic contributions to the interatomic potentials of the diatomics H2+, H2, He2+ and He2. These species, which contain one, two, three and four electrons respectively, range from the strongly (H2) to the weakly (He2) bonded chemical entities. SGF theory provides a simple conceptual model of the processes occurring during chemical bonding, and the results obtained in this work may be generalized so as to explain the bonding in larger, more complex systems. The relative merits of the perturbational and variational approaches and of the Lowdin and Gram-Schmidt orthogonalization procedures are discussed.
Reaction of 2-Ethoxy-5-methyl-1,3,2-dioxaphosphorinane-5-methanol 2-Sulfide and 4-Methyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-Sulfide With Sulfuryl Chloride: Mechanistic and Stereochemical Considerations
Authors: Kim JH , Craig DC , Gallagher MJ , Toia RF
Published: September 2010

Treatment of either cis- or trans-2-ethoxy-5-methyl-1,3,2,-dioxaphosphorinane-r-5-methanol 2-sulfide with SO2Cl2 yielded the cyclization product 4-methyl-2,6,7-trioxa-1-phosphabicyclo-[2.2.2]octane 1-oxide. In contrast, treatment of 4-methyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]-octane 1-sulfide with the same reagent gave stereospecific ring opening to trans-2-chloro-5-methyl-1,3,2-dioxaphosphorinane-r-5-methyl chloride 2-oxide.
The interaction of eye blinks and other prosodic cues in German Sign Language
Authors: Herrmann Annika
Published: September 2010

As an interface phenomenon, prosody interacts with all components of grammar, even though it is often subsumed under the broad area of phonology. In sign languages, an equivalent system of prosody reveals interesting results with regard to modality-independent notions of language structure. This paper presents data from a study on German Sign Language (Deutsche Gebärdensprache, DGS) and investigates prosodic cues on the basis of annotated video data. The focus of the study was on eye blinks and their use in prosodic structuring of signed utterances. Systematic methodology, annotation, and statistical evidence provided the basis for a thorough analysis of blinking behavior in DGS. The results suggest a consistent use of certain eye blinks as markers to indicate prosodic phrase boundaries. A constant 70%/30% ratio of prosodic and non-prosodic blinks further indicates the efficient use of this device. Even though some aspects of blinking are subject to inter-signer variation, the prosodic use of blinks is intriguingly similar across signers. However, blinks are not obligatory boundary markers in DGS. I propose an analysis that takes into account various factors such as syntactic constituency, prosodic structuring, and particularly the interplay of various nonmanuals such as eye gaze, head nods, and facial expressions. The fine-grained distinction of blinks resulting from a modified categorization for eye blinks and additional statistical computations give insight into how visual languages realize phrase boundaries and prosodic marking and to what extent they use the system consistently.
Adducins Regulate Remodeling of Apical Junctions in Human Epithelial Cells
Authors: Naydenov Nayden G. , Ivanov Andrei I.
Published: September 2010

Epithelial adherens junctions (AJs) and tight junctions (TJs) are dynamic structures that readily undergo disintegration and reassembly. Remodeling of the AJs and TJs depends on the orchestrated dynamics of the plasma membrane with its underlying F-actin cytoskeleton, and the membrane–cytoskeleton interface may play a key role in junctional regulation. Spectrin–adducin–ankyrin complexes link membranes to the actin cytoskeleton where adducins mediate specrtrin–actin interactions. This study elucidates roles of adducins in the remodeling of epithelial junctions in human SK-CO15 colonic and HPAF-II pancreatic epithelial cell monolayers. These cells expressed the α and γ isoforms of adducin that positively regulated each others protein level and colocalized with E-cadherin and β-catenin at mature, internalized and newly assembled AJs. Small interfering RNA-mediated down-regulation of α- or γ-adducin expression significantly attenuated calcium-dependent AJ and TJ assembly and accelerated junctional disassembly triggered by activation of protein kinase C. Two mechanisms were found to mediate the impaired AJ and TJ assembly in adducin-depleted cells. One mechanism involved diminished expression and junctional recruitment of βII-spectrin, and the other mechanism involved the decrease in the amount of cellular F-actin and impaired assembly of perijunctional actin bundles. These findings suggest novel roles for adducins in stabilization of epithelial junctions and regulation of junctional remodeling.
Adaptation of Agricultural and Food Systems to Climate Change: An Economic and Policy Perspective
Authors: Antle John M. , Capalbo Susan M.
Published: September 2010

Adaptation of agricultural and food systems to climate change involves private and public investment decisions in the face of climate and policy uncertainties. The authors present a framework for analysis of adaptation as an investment, based on elements of the economics, finance, and ecological economics literatures. They use this framework to assess critically impact and adaptation studies, and discuss how research could be designed to support public and private investment decisions. They then discuss how climate mitigation policies and other policies may affect adaptive capacity of agricultural and food systems. They conclude with an agenda for public research on climate adaptation.
Approximating intrinsic noise in continuous multispecies models
Authors: Scott Matthew , Poulin Francis J. , Tang Herbert
Published: September 2010

In small-scale chemical reaction networks, the local density of molecules is changed by discrete jumps owing to reactive collisions, and through transport. A systematic perturbation scheme is developed to analytically characterize these non-equilibrium intrinsic fluctuations in a multispecies spatially varying system. The method is illustrated on a variety of model systems. In all cases, the continuous approximation method is corroborated with extensive stochastic simulation. As an example of our technique applied to a spatially varying steady state, we demonstrate that a model for embryonic patterning mediated by regulatory mRNA is surprisingly robust to intrinsic fluctuations.
Thermal dynamics in general relativity
Authors: Lopez-Monsalvo C. S. , Andersson N.
Published: September 2010

We discuss a relativistic model for heat conduction, building on a convective variational approach to multi-fluid systems where the entropy is treated as a distinct dynamical entity. We demonstrate how this approach leads to a relativistic version of the Cattaneo equation, encoding the finite thermal relaxation time that is required to satisfy causality. We also show that the model naturally includes the non-equilibrium Gibbs relation that is a key ingredient in most approaches to extended thermodynamics. Focusing on the pure heat conduction problem, we compare the variational results with the second-order model developed by Israel and Stewart. The comparison shows that, despite the very different philosophies behind the two approaches, the two models are equivalent at first-order deviations from thermal equilibrium. Finally, we complete the picture by working out the non-relativistic limit of our results, making contact with recent work in that regime.
A novel minicollagen gene links cnidarians and myxozoans
Authors: Holland Jason W. , Okamura Beth , Hartikainen Hanna , Secombes Chris J.
Published: September 2010

Myxozoans are enigmatic endoparasitic organisms sharing morphological features with bilateria, protists and cnidarians. This, coupled with their highly divergent gene sequences, has greatly obscured their phylogenetic affinities. Here we report the sequencing and characterization of a minicollagen homologue (designated Tb-Ncol-1) in the myxozoanTetracapsuloides bryosalmonae. Minicollagens are phylum-specific genes encoding cnidarian nematocyst proteins. Sequence analysis revealed a cysteine-rich domain (CRD) architecture and genomic organization similar to group 1 minicollagens. Homology modelling predicted similar three-dimensional structures toHydraCRDs despite deviations from the canonical pattern of group 1 minicollagens. The discovery of this minicollagen gene strongly supports myxozoans as cnidarians that have radiated as endoparasites of freshwater, marine and terrestrial hosts. It also reveals novel protein sequence variation of relevance to understanding the evolution of nematocyst complexity, and indicates a molecular/morphological link between myxozoan polar capsules and cnidarian nematocysts. Our study is the first to illustrate the power of using genes related to a taxon-specific novelty for phylogenetic inference within the Metazoa, and it exemplifies how the evolutionary relationships of other metazoans characterized by extreme sequence divergence could be similarly resolved.
A Bayesian phylogenetic approach to estimating the stability of linguistic features and the genetic biasing of tone
Authors: Dediu Dan
Published: September 2010

Language is a hallmark of our species and understanding linguistic diversity is an area of major interest. Genetic factors influencing the cultural transmission of language provide a powerful and elegant explanation for aspects of the present day linguistic diversity and a window into the emergence and evolution of language. In particular, it has recently been proposed thatlinguistic tone—the usage of voice pitch to convey lexical and grammatical meaning—is biased by two genes involved in brain growth and development,ASPMandMicrocephalin. This hypothesis predicts that tone is a stable characteristic of language because of its ‘genetic anchoring’. The present paper tests this prediction using a Bayesian phylogenetic framework applied to a large set of linguistic features and language families, using multiple software implementations, data codings, stability estimations, linguistic classifications and outgroup choices. The results of these different methods and datasets show a large agreement, suggesting that this approach produces reliable estimates of the stability of linguistic data. Moreover, linguistic tone is found to be stable across methods and datasets, providing suggestive support for the hypothesis of genetic influences on its distribution.
What makes recognition without awareness appear to be elusive? Strategic factors that influence the accuracy of guesses
Authors: Voss Joel L. , Paller Ken A.
Published: September 2010

Various factors could conceivably promote the accuracy of guesses during a recognition test. Two that we identified in previous studies are forced-choice testing format and high perceptual similarity between the repeat target and novel foil. In restricted circumstances, the relative perceptual fluency of the target can be compared with that of the foil and used as a reliable cue to guide accurate responses that occur without explicit retrieval—a phenomenon we referred to as “implicit recognition.” In this issue, Jeneson and colleagues report a failure to replicate accurate guesses and also a tendency on the part of subjects to hazard guesses infrequently, even though testing circumstances were very similar to those that we used. To resolve this discrepancy, we developed a simple manipulation to encourage either guessing or confident responding. Encouraging guessing increased both the prevalence of guesses and the accuracy of guesses in a recognition test, relative to when confident responding was encouraged. When guessing was encouraged, guesses were highly accurate (as in our previous demonstrations of implicit recognition), whereas when confident responding was encouraged, guesses were at chance levels (as in Jeneson and colleagues' data). In light of a substantial literature showing high accuracy despite low confidence in certain circumstances, we infer that both the prevalence and accuracy of guessing can be influenced by whether subjects adopt guessing-friendly strategies. Our findings thus help to further characterize conditions likely to promote implicit recognition based on perceptual fluency.
Röntgenaufnahmen bei Großtieren unter Benutzung von Punktwert‐Tabellen
Authors: Schermer Joachim
Published: September 2010

In umfangreichen Versuchen an erwachsenen Großtieren wurden die optimalen Bedingungen für Röntgenaufnahmen ermittelt. Die erlangten Daten wurden in Punktwerten gemäß der Siemens‐Reiniger‐Röntgen‐Belich‐tungstabelle festgelegt. Diese Punktwerte gestatten eine Berechnung der Aufnahmedaten für jeden röntgenologisch erfaßbaren Körperteil und zwar unter Anpassung an die jeweilige Leistungsfähigkeit der benutzten Apparatur. Unter Berücksichtigung dieser Punktwerte ist es möglich, ohne lange Vorversuche sofort brauchbare Röntgenbilder zu erzielen.

Exposure data for Radiography in large domestic animals

From numerous observations with adult horses and cattle the optimal conditions for taking radiographs have been determined.

The data obtained are presented for use with the Siemens' Reiniger exposure table. The results provide data for all the various parts of the body that can be radiographed and make allowance for the particular apparatus used. This means that satisfactory results can be obtained without the necessity for trial exposures.

La radiographie chez les grands animaux avec l'aide de tables d'exposition par points

Dans de nombreux essais sur des grands animaux adultes, on rechercha les conditions optimales pour la radiographie. Les résultats obtenus furent traduits en points selon la table d'exposition radiographique de Siemens‐Reiniger. Ces valeurs en points permettent le calcul des données nécessaires pour chaque partie du corps susceptible d'être radiographiée, et cela en tenant compte des possibilités de l'appareil employé. En utilisant ce système par points il est possible d'obtenir tout de suite des images radiographiques utilisables, sans avoir recours à de longs essais préliminaires.

Fotografías roentgenográficas en grandes animales utilizando las tablas de exposición por puntos

En exhaustivas experiencias realizadas en animales desarrollados pertenecientes a las grandes especies se determinaron las condiciones óptimas para las fotografías de los rayos X. Los datos recogidos se determinaron en valores de puntos según la tabla de exposición roentgenográfica de Siemens‐Reiniger. Estos valores de puntos permiten calcular los datos fotográficos para cualquier parte orgánica abarcable por los rayos X, a saber bajo la adaptación en cada caso a la capacidad de rendimiento del aparato utilizado. Teniendo en cuenta estos valores en puntos es posible alcanzar inmediatamente las imágenes roentgenográficas útiles sin largas experiencias previas.