bluuebunny/crossref_metadata_2025 huggingface dataset:
Lewis-Base Adducts of Main Group 1 Metal Compounds. XV. Adducts of Lithium(I) Perchlorate With o-Methyl-Substituted Monodentate Pyridine Bases of Increasing Bulk
Authors: Harvey S , Kildea JD , Skelton BW , White AH
Published: September 2010

Whereas recrystallization of CuIClO4 from the progressively bulky pyridine bases (L) pyridine ( py ), 2-methylpyridine (2-mpy) and 2,6-dimethylpyridine (2,6-dmpy) yields adducts of progressively diminishing base stoichiometry , n = 4, 3, 2 (in [CuLn ](ClO4)), recrystallization of LiClO4 from the same bases yields adducts [Li( py )4](ClO4) and polymeric, perchlorate -bridged Li(2-mpy/2,6-dmpy)2 ClO4). The former is tetragonal, I4 a 12.479(5), c 7.009(8) � , Z 2, and isomorphous with the copper analogue; R was 0.057 for 324 'observed' reflections, and Li-N 2.O66(7)�
[cf. Cu-N, 2.046(4) � ]. Li(2-mpy)2(ClO4) is monoclinic, P21/c, a 16.004(4), b 10.020(3), c 8.831(5) �, β 99.56(3), Z 4, R 0.047 for 1402 'observed' reflections, while Li(2,6-dmpy)2(ClO4) is monoclinic, C2/c, a 22.089(9), b 10.067(5), c 15.715(6) � , β 110.54(3), Z 8, R 0.041 for 1991 'observed' reflections. The latter compounds have Li2N2O2 coordination environments about the metal of an irregular nature, presumably in consequence of ligand hindrance.
The Improved Synthesis of Boc-Abu(PO3Me2)-OH and Its Use for the Facile Synthesis of Glu-Abu(P)-Leu
Authors: Tong G , Perich JW , Johns RB
Published: September 2010

The improved synthesis of Boc -L-Abu(PO3Me2)-OH from Boc-Asp-Obut in 42% overall yield is described. This derivative was prepared in seven steps and involved initial sodium borohydride reduction of the isobutoxycarbonyl mixed anhydride of BOC-Asp-OBut and subsequent 2,2,6,6- tetramethylpiperidine-1-oxyl-catalysed sodium hypochlorite oxidation of the alcohol. The resultant aldehyde was phosphonylated by reflux with dimethyl trimethylsilyl phosphite and the trimethylsilyl group was then cleaved in situ by aqueous hydrolysis. The 4-hydroxy 4-dimethylphosphono derivative was converted into the Abu(PO3Me2) residue by reaction with thiocarbonyldiimidazole followed by radical deoxygenation of the thiocarbonylimidazolide with tributyltin hydride. The Boc and t-butyl groups were cleaved from BOC-Abu(PO3Me2)-OBut with trifluoroacetic acid and the Boc group was reintroduced to CF3CO2H.H-Abu(PO2Me2)-OH by using di-t-butyl dicarbonate to give Boc -Abu(PO3Me2)-OH as a clear oil. The optical purity of the Abu(PO3Me2) residue was established to be greater than 99.5% of the L-isomer by h.p.1.c. analysis of its L- Leu dipeptide. The protected derivative Boc-Abu(PO3Me2)-OH was used in the Boc mode of peptide synthesis for the preparation of Boc-Glu (OBz1)-Abu(PO3Me2)-Leu-OBzl in high yield, 40% CF3CO2H/CH2Cl2 being used for cleavage of the Boc group from intermediate peptides. The tripeptide was deprotected to CF3CO2H.H-Glu-Abu(P)- Leu -OH by a two-step procedure which involved initial hydrogenolytic cleavage of the benzyl groups in 50% CF3CO2H/CH3CO2H followed by cleavage of the methyl phosphate groups with either (A) 30% bromotrimethylsilane in acetonitrile, or (B) 1 M bromotrimethylsilane /l M thioanisole in trifluoroacetic acid; complete cleavage of the methyl groups was effected after 40 min and 12 h, respectively. In addition, the dipeptide Boc-Leu-Abu (P03Me2)- OBut was prepared from Boc-Abu(PO3Me2)-OBut in high yield and was readily deprotected by acidolytic cleavage of the t-butyl groups with trifluoroacetic acid followed by silylitic cleavage of the methyl phosphonate groups with 30% bromotrimethylsilane in acetonitrile, CF3CO2H.H-Leu-Abu(P)-OH being obtained in high yield.
A Mononuclear Cobalt(II) Complex Containing Pyridine Betaine and Thiocyanate Ligands: Triaquabis(pyridinioacetato-O)(thiocyanato-N)cobalt(1+) Tetra(thiocyanato-N)cobaltate(2-)
Authors: Chow MY , Mak TCW
Published: September 2010

The cobalt(II) complex [Co(C5H5NCH2CO2)2(NCS)(H2O)3]2 [Co(NCS)4] has been synthesized, and characterized by X-ray crystallography. The complex comprises distorted octahedral [CO(C5H5NCH2CO2)2(NCS)(H2O)3]+ cations, in which the cobalt atom is surrounded by two trans monodentate pyridine betaine ligands, one N-bonded thiocyanate ligand and three aqua ligands, as well as distorted tetrahedral [CO(NCS)4]2- anions. Two-thirds of the aqua ligands form intra- and inter-molecular hydrogen bonds with the coordinated and uncoordinated carboxylate oxygens , linking the cations into a one-dimensional polymeric block directed along a 21 axis.
Structural Refinement of Olivine-Type LiMgAsO4
Authors: Barbier J
Published: September 2010

The refinement of the LiMgAsO4 structure by powder neutron diffraction confirms that it is isostructural with olivine. The structure is orthorhombic, Pnma space group, with a = 10.4183(15), b = 5.9660(8), c = 4.8692(5) �, and Z = 4. The lithium and magnesium atoms are fully ordered on the octahedral sites with average bond lengths (Li-O) = 2.187, (Mg-O) = 2.108 and (As-O) = 1.672 A. LiMgAsO4 is isostructural with LiMgPO4 but not with LiMgVO4. However, a close structural relationship exists between the arsenate and the vanadate involving similar cation arrays but different anion arrays.
The Defect Fluorite Phase in the ZrO2-PrO1.5 System and Its Relationship to the Structure of Pyrochlore
Authors: Withers RL , Thompson JG , Barlow PJ , Barry JC
Published: September 2010

A detailed transmission electron microscope and X-ray powder diffraction study has been made of the so-called 'defect fluorite' phase field in the ZrO2-PrO1.5 system and of its close relationship to the pyrochlore solid solution field in the same system. Even for the lowest possible PrO1.5 content within the 'defect fluorite' phase field, it is clear that the sharp Bragg reflections characteristic of the underlying fluorite average structure are accompanied by some of the 'satellite reflections' characteristic of the pyrochlore solid solution field. As the PrO1.5 content increases, these satellite reflections increase systematically in intensity as well as sharpening very considerably. It is shown that this 'defect fluorite' phase field cannot be adequately described either in terms of random point defects within an average fluorite-type matrix or in terms of a diphasic texture of pyrochlore domains embedded coherently into a fluorite matrix, but must be regarded as enuinely intermediate between these two end-member structures and of commensurately modulated fluorite type. A group theoretical approach is used to propose a model for the structural deviation from the underlying fluorite average structure.
Synthesis of Ventilagone
Authors: Cameron DW , Crosby IT , Feutrill GI
Published: September 2010

Synthesis of ventilagone (4) from the naphthol (5) was complicated by oxidation involving the central ring and by extensive epimerization to the trans series in the course of Lewis-acid-mediated demethylation . These complications were avoided by prior protection as the acetate (23). Oxidative demethylation and subsequent hydrolysis converted the latter into the dihydroxy quinone (6), which was also accessible from the nitro compound (26). Spectroscopic procedures for determining relative stereochemistry of such systems are discussed. Compound (6) underwent radical C-methylation to give ventilagone (4).
Potential Antimalarials. XVII. Di- and Mono-Mannich Bases of 2(and 4)-[2(and 8)-Trifluoromethylquinolin-4-ylamino]phenol
Authors: Barlin GB , Nguyen TMT , Kotecka B , Rieckmann KH
Published: September 2010

Di- and mono-Mannich base
derivatives of 2(and 4)-[2(and 8)-trifluoromethylquinolin-4-ylamino]phenols have been prepared for comparison with the 7-trifluoromethyl isomers in tests for antimalarial activity. The order of activity in in vitro tests against the FC-27 ( chloroquine -sensitive) strain of Plasmodium falciparum was 7-CF3 >> 8-CF3 > 2-CF3.
Central Nervous System Active Compounds. XVII. Some Reactions of 6-Chloro-4,4-dimethyl-1,3,4,5-tetrahydro-2H-azepin-2-one and Its Dechlorinated Derivative
Authors: Hatswell MR , Prager RH , Ward AD
Published: September 2010

The vinyl chloride group of the title compound can be reduced to the enamide by using sodium metal. The enamide reacts with diborane or mercuric acetate to place a functional group at C7. The vinyl chloride is stable to hydrolysis under a variety of mild conditions but reacts with alkoxides under reflux to form a 6,7-dialkoxy derivative. A small amount of a dimer was obtained from the reaction of a mixture of unsaturated chlorocaprolactams with hydroxide.
The Trouble With Synthesis
Authors: Cornforth JW
Published: September 2010

Chemical synthesis is defined as the intentional construction of molecules by means of chemical reactions. The motives of chemists for engaging in synthesis are discussed, together with desirable developments in the art of synthesis and in the publication of its results.
Synthesis of Further Lichen Depsides
Authors: Elix JA , Barclay CE , David F , Griffin FK , Hill AM , Mcconnell DB , Wardlaw JH
Published: September 2010

The unambiguous total synthesis of 18 lichen depsides has been achieved by the condensation of an appropriately substituted orsellinic acid and protected phenol in the key step, followed by subsequent deprotection and/or secondary reduction. The natural occurrence of the first meta-depside involving substitution at the 5𔉮-position of the B-ring has been confirmed. The intermediacy of such compounds has previously been invoked to account for the probable biosynthetic interconversion of orcinol para-depsides to depsidones.
Organoamido- and Aryloxo-Lanthanoids. V. Preparations of Low-Coordinate Lanthanoid(II) Phenolates, Ln (OC6H2But2-2,6-X-4)2( thf )n (Ln = Yb or Eu; X = H, Me or BuT; N = 2 or 3) and the X-Ray Crystal Structure of Five-Coordinate [Yb (OC6H2But2-2,6-X-4)2( thf )3].thf
Authors: Deacon GB , Feng T , Mackinnon P , Newnham RH , Nickel S , Skelton BW , White AH
Published: September 2010

Lanthanoid (II) complexes of bulky aryl oxides, Ln (OC6H2But2-2,6-X-4)2 ( Ln = Yb or Eu ; X = H, Me or But) have been prepared by one or more of the following methods: ( i ) reaction of Ln (C6F5)2 with the appropriate phenol, (ii) reaction of the lanthanoid metal, Hg(C6F5)2 and the phenol, and (iii) reaction of the lanthanoid metal with the corresponding thallium(I) phenolate, in tetrahydrofuran ( thf ), and they have been isolated as Ln (OC6H2But2-2,6-X-4)2(thf)3 complexes. Crystallization of Yb (OC6H2But2-2,6-X-4)2( thf )3 (X = H or Me) from toluene yields Yb (OC6H2But2-2,6-X-4)2( thf )2. The X-ray crystal structure of [ Yb (OC6H2But3-2,4,6)2( thf )3]. thf [monoclinic, a 10.20(1), b 32.97(2), c 16.018(4) Ǻ, β 93.52(8)°, V 5375 Ǻ3, Z 4, 2734 'observed' data refined to R 0.070] shows distorted square pyramidal five coordination for ytterbium with an apical thf oxygen [ Yb -O 2.44(1)Ǻ], and transoid phenolate oxygens [ Yb -O 2.21(1), 2.22(1)Ǻ, O- Yb -O 149.0(6)°] and trans thf oxygens [ Yb -O 2.47(2), 2.48(1)Ǻ, O-Yb -O 177.3(5)°] in the square plane. Four methyl groups ( Yb…C 3.89-4.15 Ǻ) across the square plane away from the apical oxygen may block coordination of an additional ligand. X-Ray structures of Yb (OC6H2But2-2,6-Me-4)2(thf)n showing four coordination (n = 2) and five coordination (n = 3), given in a preliminary communication,1 are further discussed.
The Reaction of Some N-(Nitrophenyl)azoles With Alkali: Preparation of the Corresponding Azoxybenzenes. X-Ray Structure of 2,2′-Bis(1″,2″,4″-triazol-1″-yl)azoxybenzene
Authors: Mackay MF , Trantino GJ , Wilshire JFK
Published: September 2010

The reactions of some representative N-( nitrophenyl )azoles with boiling aqueous ethanolic potassium hydroxide solution gave the corresponding bis ( azolyl ) azoxybenzenes . It is deduced that, in these reactions, the N-attached azolyl groups concerned are acting as weak electron-withdrawing groups. The structure of 2,2′-bis(1″,2″,4″-triazol-1″-yl) azoxybenzene was determined in the solid state by X-ray crystallography. The monoclinic crystals belong to the space group P21/c with a 8.815(1), b 7.863(1), c 11.836(1) Ǻ, β 109.96(1)° and Z 2. The structure was refined to an R index of 0.041 for 1172 observed terms. The midpoint of the exocyclic N=N bond lies on an inversion centre so that the azoxy oxygen is statistically distributed between two sites. The benzene ring atoms are coplanar to within experimental error, as are the triazole ring atoms, and the dihedral angle between the perpendiculars to the two rings is 35.3(3)°.
Syntheses and Structures of Manganese(II) and Manganese(III) Nitrate Diaminosarcophagine Complexes
Authors: Creaser II , Engelhardt LM , Harrowfield JM , Sargeson AM , Skelton BW , White AH
Published: September 2010

The syntheses of [ Mn ((NH3)2sar)](NO3)4.H2O and [ Mn ((NH3)2sar)](NO3)5.2H2O,
manganese(II) and manganese(III) complexes of the cage amine ligand diaminosarcophagine ( di-aminosarcophagine = (NH2)2sar = 1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane ) in its diprotonated form are recorded, together with their single-crystal X-ray structure determinations at c. 295 K. The monoclinic P21 array of the manganese(II) complex (a 12.386(5), b 12.431(4), c 8.598(4) Ǻ, β 93.89(4)°, V 1321(1) Ǻ3,Z 2) is archetypical for similar complexes of a wide variety of transition metals; for the present determination, R was 0.027 for 2013 'observed' (I > 3σ(I)) reflections. The manganese(III) complex is monoclinic C 2/c, a 10.744(2), b 13.294(4), c 20.462(9) Ǻ, β 102.38(3)°, Z 4; R was 0.055 for 1629 'observed' reflections. Both structures show the six secondary nitrogen atoms of the ligand to be bound to the manganese ion in a configuration approximately halfway between a trigonal prism and an octahedron. The ligand is in the lel3 conformation. In the first complex, Mn -N distances, appropriate to high-spin manganese(II), range from 2.228(3) to 2.253(3) Ǻ, mean 2.238 Ǻ; in the second, surprisingly, the distances are even more closely ranged (unlike those of the sarcophagine analogue of the previous paper), 2.115(4)-2.127(4) Ǻ, the mean (2.122 Ǻ) being closely comparable to that recorded for the sar analogue, and show no appreciable variation attributable to the expected Jahn-Teller effect.
Nitrones and Oxaziridines. XLVI. Formation of Pyrrolo[3,2,1-ij]Quinolines by Intramolecular Nitrone Cycloaddition
Authors: Black DS , Keller PA , Kumar N
Published: September 2010

Intramolecular 1,3-dipolar cycloaddition occurs between nitrones derived from indole-7-carbaldehydes and adjacent allylic substituents on the indole nitrogen atoms. The resulting pyrroloquinoline derivatives (4a-i) have been characterized fully. A range of other potential precursors to cycloaddition reactions have been synthesized, but cyclization sequences have not been completed.
Rearrangements in the Molecular Ions of Some ortho-Substituted Schiff Bases
Authors: Blumenthal T , Dosen M , Gillis RG , Porter QN
Published: September 2010

Under electron ionization conditions, the ortho-substituted Schiff bases N-benzylidene-o-toluidine (1a), N-(o-methylbenzylidene)aniline (1b), N-salicylideneaniline (1c) and N-(o-methoxybenzylidene)aniline (1d) give fragment ions which have been shown by collision-activated mass-analysed ion kinetic energy spectra to have the structure of the protonated molecular ions of indole (2), benzofuran (3), and 1,2-benzisoxazole (4). The molecular ion of N-(o-methylbenzylidene)-o-toluidine (1f) gives as fragment ions not only the protonated molecular ion (2) of indole and the tropylium ion but also the molecular ion of anthracene. Attempts to find supporting evidence for a mechanism for this rearrangement by deuterium labelling of a methyl group in (1b), such as (1g), have been unsuccessful.
The Structure of a New C25 Isoprenoid Alkene Biomarker From Diatomaceous Microbial Communities
Authors: Summons RE , Barrow RA , Capon RJ , Hope JM , Stranger C
Published: September 2010

A new C25 highly branched alkadiene (5) has been isolated from the diatomaceous benthic microbial communities of Hamelin Pool, Western Australia. The structure (5) was determined by detailed n.m.r. and mass spectral analysis, as well as by chemical degradation. Carbon isotopic measurements on this and related isoprenoids were consistent with an origin from diatoms. The role of (5) and related metabolites as biological marker compounds is discussed.
Molecular Cocrystals of Carboxylic Acids. XII. Structures of the 1 : 1 Adducts of 4-Nitrobenzoic Acid and 3,5-Dinitrobenzoic Acid With N,N'-Bis(1-methylethyl)-6-methylthio-1,3,5-triazine-2,4-diamine (Prometryn)
Authors: Lynch DE , Smith G , Byriel KA , Kennard CHL
Published: September 2010

Two 1:1 molecular adducts
of the s- triazine herbicide prometryn [N,N′- bis (1-methylethyl)-6-methylthio-1,3,5-triazine-2,4-diamine] with 4-nitrobenzoic acid, [(C7H4NO4)-(C10H20N5S)+.H2O]
(1), and with 3,5-dinitrobenzoic acid, [(C7H3N2O6)-(C10H20N5S)+] (2), have been prepared and characterized. The structure of (1) has been determined by X-ray methods and refined to a residual R 0.055 for 2072 observed reflections. Crystals are monoclinic, space group P21/c with Z 4 in a cell of dimensions a 7.191(4), b 28.359(8), c 10.990(6) Ǻ, β 104.75(3)°. The carboxylic acid group protonates a nitrogen of the triazine ring and is involved in a cyclic hydrogen-bonding association with this and with a secondary amine of the side chain [N…O, 2.76, 2.78(1)Ǻ], while the second amine is associated with the lattice water [N…O, 2.90(1)Ǻ]. Spectroscopic methods have been used to confirm the similarity of the molecular associations involving the carboxylic acid groups of the aromatic acids and prometryn in both (1) and (2).
The Stereochemistry of Organometallic Compounds. XXXIX. Hydroformylation of Alkenes Containing Sulfur and Oxygen Substituents: a Potential Route to 1,4-Dialdehydes
Authors: Campi EM , Jackson WR , Perlmutter P , Tasdelen EE
Published: September 2010

Rhodium-catalysed hydroformylation of a series of unsaturated thioethers, dithians , dioxans and dioxolans has been shown to give aldehydes in very good yield. The regioselectivity in some cases appears to be influenced by coordination between the rhodium catalyst and the sulfur substituent especially when dodecacarbonyltetrarhodium is used as the catalyst precursor. At tempts to convert dithian and dioxan aldehydes into 1,4-dialdehydes were unsuccessful.
Preparation of Rhenium Diamino Dithiolate Complexes. The X-Ray Crystal Structure of Oxo(1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium
Authors: Jackson TW , Kojima M , Lambrecht RM
Published: September 2010

The complexes oxo (1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium[ ReO ( tedadt )], oxo (1,1,8,8-tetraethyl-4,4-dimethyl-3,6-diazaoctane-1,8-dithiolato)rhenium [ ReO ( tedmdadt )] and (1,1,4,4,8,8-hexamethyl-3,6-diazaoctane-1,8-dithiolato) oxorhenium [ ReO ( hmdadt )] were prepared. The crystal structure of the complex ReO ( tedadt ) was determined by X-ray crystallography to be a hydrogen-bonded dimer . This is the first example of intermolecular hydrogen bonding in rhenium diamino dithiolate ( dadt ) complexes.
Cupric Ion Chelation Assisted Synthesis of N(α)-Protected N(ω)-Acridin-9-yl α,ω-Diamino Carboxylic Acids
Authors: Chiu FCK , Brownlee RTC , Phillips DR
Published: September 2010

The synthesis of Nα-protected Nω-acridin-9-yl derivatives of the α,w-diamino carboxylic acids ornithine and lysine is reported. Direct introduction of the acridin-9-yl moiety to the amino side chain of the free amino acid was achieved in methanol through temporary copper(II) chelation protection of the α-amino and
carboxy groups. Nα-Fmoc protection was introduced by using N-(fluoren-9-ylmethoxycarbonyloxy)succinimide in aqueous dioxan.
On the Synthesis of Scymnol
Authors: Amiet RG , Kalafatis N , Macrides T
Published: September 2010

Reinvestigation of a reported synthesis of scymnol (5β-cholestane-3α,7α,12α,24,26,27-hexol) has cast doubt on the success of that synthetic route. A modified synthetic pathway has been developed and scymnol, racemic at C24, has been unequivocally prepared from cholic acid. Extensive proton and 13C n.m.r. spectroscopy has been used to confirm the structure of the product. A new, simple method of desulfation of natural scymnol sufate has been developed.
Compounds of 5-Hydroxymethyl-5-nitro(and 5-amino)hexahydropyrimidine-1,3-bisethanol With Nickel(II). The Structure of mer-Bis(5-amino-5-hydroxymethylhexahydropyrimidine-1,3-bisethanol-N1,N5,O1)nickel(II) Acetate Perchlorate
Authors: Curtis NF , Morgan KR , Siriwardena A , Weatherburn DC
Published: September 2010

Reaction of a nickel(II) salt, 2-aminoethanol, formaldehyde and nitromethane yields a nickel(II) complex of 5-hydroxymethyl-5-nitrohexahydropyrimidine-1,3-bisethanol, hnpdH2, isolated as sparingly soluble blue salts of the cation [Ni( hnpdH )]+, and as insoluble green [Ni( hnpd )]. The nitro group of the ligand was reduced by catalytic hydrogenation to form 5-amino-5-hydroxymethylhexahydropyrimidine-1,3-bisethanol, ahpdH, isolated as salts of cations [Ni( ahpdH )2]2+ and [Ni( ahpdH )( ahpd )]+. The structure of [Ni( ahpdH )2] (CH3COO) (ClO4), determined by X-ray diffractometry, showed a cis NiN4O2 octahedral arrangement, with two ahpdH ligands in meridional coordination by the primary amino and one tertiary amino nitrogens, and the linked hydroxyethyl oxygen atom of each ligand. [ mer-Bis (5-amino-5- hydroxymethylhexahydropyrimidine-1,3-bisethanol-N1,N5,O1)nickel(II) acetate perchlorate, triclinic, space group Pī, a 9.233(2), b 9.567(3), c 16.775(3) Ǻ, α 81.87(2), β 76.08(2), γ 84.15(2)°p;, R 0.0325, Rw 0.0334 for 3859 reflections.]
Diastereoselective Propionitrile Oxide Cycloaddition Reactions With Some γ-Substituted α-Methylene-γ-butyrolactones
Authors: Pereira SM , Savage GP , Simpson GW , Greenwood RJ , Mackay MF
Published: September 2010

A number of γ-substituted α-methylene-γ-butyrolactone derivatives underwent 1,3-dipolar cycloaddition with propionitrile oxide to give spiro Δ2-isoxazolines. The reaction proceeded regiospecifically and with high diastereoselectivity. The products of anti addition predominated. The regiochemistry of addition and relative stereochemistry of the products were determined by a combination of n.O.e ., HETCOR and DOUBTFUL n.m.r. experiments. The assignment was confirmed in one case by X-ray crystallography.
An Efficient Synthesis of (2S) and (2R)-N-Benzoyl-2-t-butyl-4-methyleneoxazolidin-5-one
Authors: Beckwith ALJ , Pyne SG , Dikic B , Chai CLL , Gordon PA , Skelton BW , Tozer MJ , White AH
Published: September 2010

An efficient synthesis of the title compounds in high enantiomeric purity (>98%) involves bromination under photolytic conditions of (2S)- or (2R)-oxazolidinones derived from (S)-alanine followed by treatment of the products with sodium iodide in refluxing acetone. A room-temperature single-crystal X-ray study of (2S,4Z)-N-benzoyl-4-bromomethylene-2-t-butyloxazolidin-5-one is recorded.
Cycloheptatriene Norcaradiene Equilibrium in Dimethyl trans-3,8-Dihydroheptalene-3,8-dicarboxylate
Authors: Menzek A , Balci M
Published: September 2010

Diels-Alder cycloadditions of dienophiles , such as 4-phenyl-1,2,4-triazoline-3,5-dione, dimethyl acetylenedicarboxylate, dimethyl fumarate , diethyl azodicarboxylate , maleic anhydride, benzyne and p-benzoquinone, to dimethyl trans-3,8-dihydrohexalene-3,8-dicarboxylate (4) have been investigated, and monoaddition products (9)-(16) have been isolated. It has been shown that a second addition to this system occurs only with singlet oxygen and with benzyne. Furthermore, it has been established that the second addition is retarded because of the strain in the cycloheptatriene molecule. The anti bicyclic endoperoxides (21)-(25) formed have been converted, either on heating or in a Co( tpp )- catalysed reaction, into the corresponding bisepoxides (27)-(31).
Calixarene Phosphorylation: Cation Control of Reaction Pathways
Authors: Byrne LT , Harrowfield JM , Hockless DCR , Peachey BJ , Skelton BW , White AH
Published: September 2010

The hydroxide ion catalysed phosphorylation of p-t- butylcalix [4] arene by diethyl chlorophosphate under heterogeneous conditions shows a marked sensitivity to the nature of the phase transfer catalyst used. Thus, substitution of tetraethylammonium bromide for the tetrabutylammonium bromide prescribed for the synthesis of the calixarene tetraphosphate leads to a major reaction product becoming a bis (phosphate) in which the calixarene binds as a unidentate ligand to one phosphorus and as a bidentate ligand to the other. An X-ray crystal structure analysis on this new compound shows the calixarene to adopt a somewhat distorted 'cone' conformation with an unusual orientation of one of the t-butyl substituents into the cone cavity. It also reveals that a significant diastereoselectivity must operate in the formation reaction. The only other reaction product detected in this system appears to be the calixarene tetraphosphate in a partial cone conformation.
Synthesis, Spectroscopy and Structure of the Cobalt(III) Complex of the Hexadentate Ligand 5-(4-Amino-2-thiabutyl)-5-methyl-3,7-dithianonane-1,9-diamine
Authors: Donlevy TM , Gahan LR , Hambley TW , Mcmahon KL , Stranger R
Published: September 2010

A revised synthesis of the hexadentate ligand 5-(4-amino-2-thiabutyl)-5-methyl-3,7-dithianon- ane-1,9-diamine (N3S3) is reported. Reaction between the sodium salt of 2-aminoethanethiol and 1,1,1-tris([( tolylsulfonyl )oxy]methyl)ethane in refluxing ethanol results in the formation of the hexadentate ligand N3S3. The preparation of the nickel(II) and cobalt(III) complexes is reported. The crystal structure of [Co(N3S3)](ClO4)3.H2O has been determined by X-ray diffraction methods and refined to a residual of 0.044 for 3696 independent observed reflections. The crystals are monoclinic, P21/n, a 9.314(4), b 15.581(6), c 17.026(3) Ǻ, β 90.30(4)°. Low temperature (c.10 K) absorption spectra are reported for [Co(N3S3)]3+ and the analogous encapsulated complex [Co(AMN3S3sarH)]4+ where both the spin-allowed 1A1g → 1T1g, 1T2g and spin-forbidden 1A1g → 3T1g, 3T2g were observed. Ligand -field calculations based on octahedral symmetry result in the ligand -field parameters B 461, C 3075, Dq 2303 cm-1, and B 462, C 3085, Dq 2266 cm-1 for the [Co(N3S3)]3+ and [Co(AMN3S3sarH)]4+ complexes, respectively. A systematic reduction occurs in the Racah B parameter of between 25 and 30 cm-1 for each additional thioether donor in the series of complexes N6-xSx (x = 0, 1, 2, 3). In addition, there is evidence for a progressive increase in the Racah C/B ratio with increasing number of thioether donors in this series.
Organoamido- and Aryloxo-lanthanoids. IX. Preparations and Structures of Tris(η2-3,5-diphenyl-pyrazolato)lanthanoid(III) Complexes With Triphenylphosphine Oxide and Tetrahydrofuran
Authors: Cosgriff JE , Deacon GB , Gatehouse BM
Published: September 2010

From reaction of lanthanoid metals with bis ( pentafluorophenyl )mercury and 3,5-diphenylpyrazole (HPh2pz) in 1,2-dimethoxyethane ( dme ) and treatment of the products with triphenylphosphine oxide, the complexes [ Ln (η2-Ph2pz)3(OPPh3)2].( dme )n ( Ln = Er or Nd , n = 1; Ln = La, n = 0.6) have been isolated. An X-ray crystal structure shows that the erbium complex [monoclinic, space group C2, a 22.08(3), b 14.30(1), c 13.37(1) Ǻ, β 124.09(7)°, Z 2 2730 'observed' data refined to R 0.046] is monomeric , with eight coordination of the metal. There is a trigonal bipyramidal arrangement of the centre ( Cen ) of the N-N bonds of three η2-3,5-diphenylpyrazolate groups ( ΣCen-Er-Cen 360°; ( Er -N) 2.344 Ǻ) and the oxygens of two equivalent trans triphenylphosphine oxide ligands [O- Er -O 176(1)°; Er -O 2.207(9)Ǻ]. Unit cell data indicate that the neodymium analogue [monoclinic, space group C2, a 23.01(3), b 14.94(2), c 13.82(2) Ǻ, β 123.65(8)°] is isostructural with the erbium complex. An analogous reaction of lanthanum or neodymium metal, Hg(C6F5)2, and HPh2pz in tetrahydrofuran ( thf ) gives [ Ln (η2-Ph2pz)3( thf )3]. thf ( Ln = La or Nd ). The X-ray crystal structure of the neodymium complex [orthorhombic, space group P212121, a 14.009(9), b 16.280(8), c 22.640(16)Ǻ, Z 4, 2967 'observed' data refined to R 0.046 reveals a nine-coordinate monomer with three η2-Ph2pz ligands [ Nd -N 2.420(10)-2.524(8)Ǻ] and three thf ligands [ Nd -O 2.497(8)-2.587(8)Ǻ]. There is a trigonal prismatic arrangement of the centres of the N-N bonds and the oxygen donor atoms.
Synthesis of the Troponoid Natural Product Nezukone Via Sequential Rearrangement of Two Isomeric Precursors
Authors: Banwell MG , Cowden CJ , Gravatt GL , Rickard CEF
Published: September 2010

Nezukone (1) has been synthesized in seven steps from the readily available Δ3-trinorcarene (4). Key features of the sequence used include formation of the bicyclic isomer (2) of compound (1). Base-promoted isomerization of compound (2) followed by acidic workup then produced the isolable but highly unstable heptafulvenol (3), an extended enolic tautomer of nezukone (1). Under mildly basic conditions compound (3)
rearranged to give the natural product (1). The X-ray crystal structure of the ring-fused cyclobutanone (8) is reported.
Diammonium Salts Derived From 1,4-Diazabicyclo[2.2.2]octane
Authors: Bayada A , Lawrance GA , Maeder M
Published: September 2010

The syntheses of a range of quaternary diammonium and some monoammonium salts derived from 1,4-diazabicyclo[2.2.2]octane with N-alkyl arms or N-alkyl arms terminated by a functional group are reported. In aqueous solution they are susceptible to only very slow Hofmann elimination, and the kinetics were investigated for the 1-(2′-ammonioethyl)-4-dodecyl-1,4-diazoniabicyclo[2.2.2]octane ion, which undergoes a base-induced elimination ( kOH 6.9×10-4 dm3 mol-1 s-1 at 55°C) consistent with an ElcB mechanism. In aqueous solution, the diammonium cations are not oxidized but undergo irreversible electrochemical reduction below -1.2 V v . Ag/ AgCl , with the reduction potential apparently influenced by the electron-withdrawing or -donating nature of substituent arms.
Observations on the Mechanism of Halogen-Bridge Cleavage by Unidentate Ligands in Square Planar Palladium and Platinum Complexes
Authors: Black DS , Deacon GB , Edwards GL
Published: September 2010

Cyclo-palladation and - platination of nitrogen donor ligands lead to insoluble μ- chloro dimers which give μ- bromo and μ- iodo dimers on metathesis with the appropriate lithium halide. Addition of pyridine or 2,6-dimethylpyridine to the cyclopalladated dimers gives monomeric complexes with the halogen trans to the metal-carbon bond, whereas addition of 2,6-dimethylpyridine to the cycloplatinated complexes gives the isomer with the halogen cis to the metal-carbon bond. The results are discussed in terms of the mechanism of the bridge cleavage reaction.
DNA Binding Compounds. V. Synthesis and Characterization of Boron Containing Bibenzimidazoles Related to the DNA Minor Groove Binder, Hoechst-33258
Authors: Kelly DP , Bateman SA , Martin RF , Reum ME , Rose M , Whittaker ARD
Published: September 2010

The synthesis and characterization of four novel boron-containing bibenzimidazoles related
to the DNA minor groove binder Hoechst 33258 are reported. Such compounds, particularly
their 1�B-enriched forms, have potential as agents for boron neutron capture therapy which
is used in the treatment of cancers.
The Chlorination of Some Substituted 2,4-Dimethylphenols
Authors: Gordon JLM , Hartshorn MP , Martyn RJ , Morgan AJ , Robinson WT , Wright GJ
Published: September 2010

Chlorination reactions of 2-chloro-3,4,6-trimethylphenol (4), 2-chloro-4,6-dimethylphenol (5) and 3-chloro-2,4,6-trimethylphenol (6) are described. In acetic acid or acetic anhydride solution, chlorinations yield predominantly the corresponding 4-chlorocyclohexa-2,5-dienones (8), (17a) and (29), but in carbon tetrachloride containing pyridine products are formed which result from the modification of the 4-methyl group in each substrate. X-Ray crystal structure analyses are reported for compounds (7), (14), (28) and (31).
Molecular Cocrystals of Carboxylic Acids. XIV. The Crystal Structures of the Adducts of Pyrazine-2,3-dicarboxylic Acid With 4-Aminobenzoic Acid, 3-Hydroxypyridine and 3-Amino-1,2,4-triazole
Authors: Lynch DE , Smith G , Byriel KA , Kennard CHL , Whittaker AK
Published: September 2010

The 1:1 molecular adducts of pyrazine-2,3-dicarboxylic acid with 4-aminobenzoic acid, [(C6H3N2O4)-(C7H8NO2)+], 3-hydroxypyridine, [(C6H4N2O4) (C5H5NO)], and 3-amino-1,2,4-triazole, [(C6H3N2O4)-(C2H5N4)+] have been prepared, and their structures determined by X-ray diffraction methods. All structures involve intra- and inter-molecular hydrogen-bonding interactions. The 1:2 complex of pyrazine-2,3-dicarboxylic acid with triphenylphosphine oxide has also been prepared, and characterized by using spectroscopic methods.
Single Crystal X-Ray Structural Characterization of [BiX2(S2CNEt2)]Infinity∞, X=Cl, Br
Authors: Bharadwaj PK , Lee AM , Skelton BW , Srinivasan BR , White AH
Published: September 2010

Single-crystal room-temperature X-ray structure determinations of the title compounds have been carried out. The two compounds are isomorphous, and isomorphous with the previously determined iodide analogue, being monoclinic, P 21/c, a ≈ 10.0, b ≈ 14.9, c ≈ 7.8 Ǻ, β ≈ 92°, Z = 4 formula units; residuals were 0.037, 0.036 for 2197, 1654 'observed' reflections for X = Cl , Br respectively. As in the iodide, the complexes are infinite polymers, with successive bismuth atoms bridged by the two halides and one sulfur atom of the ligand , which also chelates each bismuth. The structure determination of C5H5NCONEt2]2 [Cl5Bi(NC5H5)], isostructural with its thiocarbamoyl analogue, is also recorded.
The Reaction of a Nitro-Capped Cobalt(III) Cage Complex With Base: the Crystal Structure of a Contracted Cage Complex, and the Mechanism of Its Formation
Authors: Geue RJ , Osvath P , Sargeson AM , Acharya KR , Noor SB , Row TNG , Venkatesan K
Published: September 2010

The synthesis, properties and crystal structure of the cage complex (1-hydroxy-8-methyl-3,6,10,13,15,18-hexaazabicyclo[6.6.5] nonadecane )cobalt(III) chloride hydrate ([Co( Me,OH-absar )]Cl3.H2O) are reported. The mechanism of the formation of this contracted cavity cage from a nitro-capped hexaazabicycloicosane type cage has been investigated. Treatment of (1- methyl-8-nitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane )cobalt(III) chloride ([Co(Me,NO2- sar )]3+) with excess base in aqueous solution leads initially to rapid (t½. < 1 ms) and reversible deprotonation of one coordinated secondary amine. This species undergoes a retro-Mannich type reaction and imine hydrolysis (t½ ≈ 90 s). Quenching the reaction with acid gives rise to a pair of isomeric intermediate species which have been isolated and characterized. They have a pendant arm macrocyclic structure, resulting from the loss of a methylene unit from one of the arms of the cap. Heating either isomer in aqueous solution gives the new cage compound with the contracted cap. It is postulated that this occurs through a Nef reaction, resulting in the formation of a ketone which then condenses with the coordinated primary amine. A comparison with the corresponding bicycloicosane analogue indicates a reduced chromophoric cavity size for the contracted cage. The reduction potential of the cobalt(III)/cobalt(II) couple is 170 mV more negative for the smaller cage, and, in the electronic spectrum of the cobalt(III) complex, the d-d transitions are both shifted to higher energy, corresponding to a stronger ligand field.
Phosphinegold(I) Complexes Containing the Purine-6-thiolate Anion, and Their Antiarthritic Activity
Authors: Cookson PD , Tiekink ERT , Whitehouse MW
Published: September 2010

A series of complexes of the general formulae R3PAu(6-mp), R3P = Et3P, Ph3P, Cy3P, PhMe2P, (o-tol)3P, (m-tol)3P or (p-tol)3P, (AuCl)Ph2P(CH2)nPPh2(Au(6-mp)), n = 2 or 3, and Ph2P(CH2)nPPh2(Au(6-mp))2, n = 1, 2 or 3 and 6-mp is the anion derived from 6-mercaptopurine (purine-6-thiol), have been prepared and characterized by spectroscopic methods (i.r., 1H, 13C, 31P n.m.r. and f.a.b. m.s.) and, in the case of the Ph3PAu(6-mp) complex, by single-crystal X-ray diffraction methods. The spectroscopic data show that the 6-mp ligand coordinates as a thiolate ligand and that the gold atoms exist in linear P-Au-S (or P-Au-Cl) geometries. This has been confirmed by an X-ray study on Ph3PAu(6-mp), isolated as an ethanol solvate; the study shows the gold atom to be linearly coordinated by the phosphorus and sulfur atoms: Au-P(1) 2.237(2), Au-S(6) 2.287(1) Ǻ and P-Au-S 173.71(6)°. Crystals of Ph3PAu(6-mp).EtOH are triclinic, space group Pī, with unit cell dimensions a 11.066(3), b 13.552(3), c 8.705(2) Ǻ, α 91.51(2), β 113.06(2), γ 89.69(2)°, V 1200.8(5) Ǻ3, Z 2. The structure was refined by a full-matrix least-squares procedure to R 0.034 for 3978 reflections with I ≥ 3.0σ(I). Preliminary results of testing for antiarthritic activity among the new complexes in rats are also reported showing that some of them are more potent/less toxic than current gold(I) thiolates used clinically.
Synthesis of 6-Methoxy-2-methyl-2-[(1'-methyl-2',5'-dioxocyclopentyl)methyl]-3,4-dihydro-naphthalen-1(2H)-one: Its Novel Base-Catalyzed Rearrangement to a Hydrophenanthrene Keto Acid
Authors: Collins DJ , Fallon GD , Skene CE
Published: September 2010

Reaction of 2-dimethylaminomethyl-6-methoxy-3,4-dihydronaphthalen-1(2H)-one (7) with 2-methylcyclopentane-1,3-dione gave 64% of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one(6a), which with 1 equiv. of ethylene glycol in refluxing benzene in the presence of 4-toluenesulfonic acid yielded a diastereomeric mixture of the 2′,2̶-ethylenedioxy derivatives (13a,b); the major diastereomer (13a) was shown to have 1′SR,2RS stereochemistry by X-ray crystallography. With an excess of ethylene glycol and prolonged reflux the triketone (6a) underwent aldol cyclization/acetalization to give 9,9,12,12-bis(ethylenedioxy)-3-methoxy-8-methyl-5,6,8,9,10,11-hexahydro-8,11-methano-7H-cyclohepta[a]naphthalene (19). With pyridinium 4-toluenesulfonate as catalyst, aldol cyclization was avoided, and the tri-ketone (6a) afforded 2-[(2′,2′,5′,5′-bis(ethylenedioxy)-1′-methylcyclopentyl)methyl]-6-methoxy-3,4-dihydronaphthalen-1(2H)-one (15). The triketone (6a) and its monoacetal (13a,b) were susceptible to reverse Michael cleavage in reactions with nucleophiles under either acidic or basic conditions. Methylation of the keto diacetal (15), followed by acid hydrolysis, gave 6-methoxy-2-methyl-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (6b); 2-[(2′,2′-ethylenedioxy-1′-methyl-5′-oxocyclopentyl)methyl]-6-methoxy-2-methyl-3,4-dihydronaphtha - len-1(2H)-one (32), resulting from incomplete hydrolysis, was shown to have 1′RS,2RS stereochemistry by X-ray crystallography. The triketone (6b) underwent a novel base-catalysed rearrangement reaction to give 7-methoxy-2ξ,10a-dimethyl-3-oxo-1,2,3,9,10,10a-hexahydrophenanthrene-4-acetic acid (33) which readily afforded the corresponding enol lactone (35).
The Structure and Synthesis of 4-Oxypannaric Acid 2-Methyl Ester, a Dibenzofuran From the Lichen Leproloma diffusum
Authors: Elix JA , Elix JA , Naidu R , Naidu R , Laundon JR , Laundon JR
Published: September 2010

The structure of the major dibenzofuran present in the lichen Leproloma diffusum has been shown to be that of 4-oxypannaric acid 2-methyl ester (2-methyl hydrogen 3,4,9-trihydroxy-1,7-dimethyldibenzofuran-2,6-dicarboxylate) (2). The structure of (2) was confirmed by total synthesis, achieved through a biomimetic-type approach using palladium(II) acetate in the key cyclization step. Partial synthesis of the corresponding dimethyl ester (8) was effected starting from natural pannaric acid 6-methyl ester (6).
Selective Bromochlorination of endo-1,4-Dibromotricyclo[5.2.1.02,6]deca-3,8-diene-5,10-dione 10-Ethylene Acetal at the Conjugated Carbon-Carbon Double Bond
Authors: Gable RW , Parker KJ , Tsanaktsidis J
Published: September 2010

Exposure of (1) to bromine in thionyl chloride/ dimethylformamide produced (5), the result of regio- and stereo-selective addition of bromine chloride across the carbonyl-conjugated double bond. The structure of (5) was determined by X-ray crystallography, and its mode of formation is discussed in terms of the carbonyl attack mechanism.
Photochemical Nitration by Tetranitromethane. XIV. The Formation of 1,3-Dipolar Nitro Addition Products From the Photochemical Reaction of 1,2-Dimethylnaphthalene and Tetranitromethane
Authors: Butts CP , Calvert JL , Eberson L , Hartshorn MP , Maclaga n , Robinson WT
Published: September 2010

Photolysis of the 1,2-dimethylnaphthalene/tetranitromethane charge-transfer complex yields the triad of 1,2-dimethylnaphthalene radical cation, nitrogen dioxide, and trinitromethanide ion. Recombination of this triad gives predominantly the adducts (13)-(16), each of which is formed by attack of the trinitromethanide ion at C4 of the 1,2-dimethylnaphthalene radical cation. Thermal cycloaddition in adducts (13) and (16) gives the cycloadducts (12) and (17) respectively.
The Synthesis and Characterization of Decaphenyltitanocene Dichloride, [Ti(η5-C5Ph5)2Cl2], and of [Ti(η5-C5Ph5)((c-C6H11)7Si7O12)], the First Pentaphenylcyclopentadienyl Polyhedral Oligosilsesquioxane
Authors: Field LD , Lindall CM , Maschmeyer T , Masters AF
Published: September 2010

The syntheses and characterization of the compounds [Ti(η5-C5Ph5)2Cl2] and [Ti(η5-C5Ph5)((c-C6H11)7Si7O12)] by infrared, 1H, 13C and 29Si n.m.r. and mass spectroscopy are described.
Molecular Cocrystals of Carboxylic Acids. XVII. Spectral Characterization of the Adducts of Triphenylphosphine Oxide With Substituted Phenoxyacetic Acids and the Crystal Structure of the 1 : 1 Adduct With (4-Chloro-2-methylphenoxy)acetic Acid
Authors: Lynch DE , Smith G , Byriel KA , Kennard CHL , Whittaker AK , Hanna JV
Published: September 2010

A series of 1:1 molecular adducts of triphenylphosphine oxide ( tppo ) with substituted phenoxyacetic acids has been prepared and characterized by using infrared, solid-state 1H and 31P n.m.r. spectroscopy, and X-ray powder diffraction methods. The crystal structure of one of these, with the herbicidally active (4-chloro-2-methylphenoxy)acetic acid ( mcpa ),[( tppo )( mcpa )], has been determined by X-ray diffraction methods. This compound is isomorphous with the tppo adduct of (2,4-dichlorophenoxy)acetic acid. The title compound has two independent and different molecular adducts in the asymmetric unit each with strong hydrogen-bonding interactions between the carboxylic acid proton and the phosphoryl oxygen of tppo [O...O, 2.579, 2.647(9)Ǻ].
Aryne Chemistry of Podocarpic Acid Derivatives
Authors: Cambie RC , Higgs PI , Rutledge PS , Woodgate PD
Published: September 2010

The anthranilic acid (2), a key intermediate for the generation of an aryne at C13 of podocarpic acid derivatives, was synthesized from the 14-amino compound (5) which in turn was generated regiospecifically in high yield by treatment of the 13-bromo compound (25) with sodamide in liquid ammonia. The amine was converted into the anthranilic acid by two separate routes: firstly by directed lithiation and trapping of the lithium species with a CO2 moiety, and secondly by oxidative cleavage of an isatin fused across positions 13 and 14.
Potential Antimalarials. XXI. Mannich Base Derivatives of 4-[7-Chloro(and 7-trifluoromethyl)quinolin-4-ylamino]phenols
Authors: Barlin GB , Ireland SJ , Nguyen TMT , Kotecka B , Rieckmann KH
Published: September 2010

Syntheses are reported for 4-(7-chloroquinolin-4-ylamino)-2,6-bis(piperidin-1-ylmethyl)phenol (2) and its 3-fluoro and 3-piperidinyl derivatives. Some mono-Mannich analogues with 2-fluoro, 2-t-butyl and 3-trifluoromethyl substituents have also been prepared. In tests for antimalarial activity against the FC-27 and K-1 isolates of Plasmodium falciparum in vitro, compound (2) proved to be the most active (IC50 6.3-12.5 nM).
Synthesis of the Avocado Antifungal, (Z,Z)-2-Hydroxy-4-oxohenicosa-12,15-dien-1-yl Acetate
Authors: Bull SD , Carman RM
Published: September 2010

A synthesis of the avocado antifungal, (Z,Z)-2-hydroxy-4-oxohenicosa-12,15-dien-1-yl acetate (1a), confirms the structure of the compound as isolated from both avocado fruit and leaves, and provides the absolute configuration of the natural lipid.
Synthesis of Activated 3-Arylindoles
Authors: Black DS , Bowyer MC , Bowyer PK , Ivory AJ , Kim M , Kumar N , Mcconnell DB , Popiolek M
Published: September 2010

A wide range of substituted 3-aryl-4,6-dimethoxyindoles (6) has been synthesized from the related α-anilinoacetophenones (5), in which the nitrogen atom is protected by a trifluoroacetyl or acetyl group. This method has led to the synthesis of a 3,7′-biindolyl (12).
Imidazo[1,2-b]pyridazines. XVII. Synthesis and Central Nervous System Activity of Some 6-(Alkylthio and chloro)-3-(methoxy, unsubstituted and benzamidomethyl)-2-arylimidazo[1,2-b]pyridazines Containing Methoxy, Methylenedioxy and Methyl Substituents
Authors: Barlin GB , Davies LP , Davis RA , Harrison PW
Published: September 2010

Syntheses are reported for 6-( methylthio, ethylthio, propylthio, substituted benzylthio and chloro )-3-( methoxy, unsubstituted and benzamidomethyl )-2-arylimidazo[1,2-b] pyridazines containing methoxy, methylenedioxy and methyl groups attached to phenyl substituents . In tests of the ability of these compounds to displace [3H]diazepam from rat brain membranes, 3-methoxy-6-(3′,4′-methylenedioxybenzylthio)-2- (3′,4′-methylenedioxyphenyl) imidazo [1,2-b] pyridazine (IC50 1 nM) bound most strongly; methylenedioxy groups were beneficial to activity whereas polymethoxy or dimethyl substituents were generally detrimental.
Tris(N,N-dialkyldithiocarbamato-S,S')thiotungsten(VI) Complexes and the X-Ray Crystal Structure of [WS(S2CNEt2)3]BF4
Authors: Young CG , Kocaba TO , Sadek M , Brownlee RTC , Tiekink ERT
Published: September 2010

The orange, diamagnetic compounds [WS(S2CNR2)3]X(R = Me, X- = BF4-,
BPh4-;R = Et, X- =BF4-) were prepared by reacting WSCl4 and Me3SiS2CNR2 in dichloromethane, followed by metathesis with NaX in methanol. The compounds were characterized by elemental analysis, infrared and variable-temperature 1H n.m.r. spectroscopy and X-ray crystallography. Crystals of [WS(S2CNEt2)3] BF4 were monoclinic, space group P21/a with a 12.293(1), b 17.229(5), c 14.257(2) Ǻ,β 113.69(1)°, V 2765(2) Ǻ3 and Dc = 1.796 g cm-3 for Z = 4. The structure was solved by the Patterson method and refined by a full-matrix least-squares procedure, 3961data being used, to a conventional R value of 0.039 ( Rw = 0.040). The seven-coordinate cation possesses a pentagonal-bipyramidal geometry; the terminal thio ligand [W=S 2.127(2)Ǻ] occupies an axial position, a unique dithiocarbamate ligand spans the other axial position and an equatorial position while the two other dithiocarbamate ligands occupy the four remaining equatorial sites.
The Structures of Four Tryptophyllin and Three Rubellidin Peptides From the Australian Red Tree Frog Litoria rubella
Authors: Steinborner ST , Gao CW , Raftery MJ , Waugh RJ , Blumenthal T , Bowie JH , Wallace JC , Tyler MJ
Published: September 2010

The peptide content of the glandular secretions of Litoria rubella specimens collected from Derby and Lake Argyle (Kimberley region of Western Australia) and from near Darwin in the Northern Territory are all quite different; this suggests that there are different frog populations in these three areas. These different populations may be indicative of either different species or different sub-species of frog. There are two separate families of peptides in the glandular secretion of 'Litoria rubella': ( i ) those corresponding to the tryptophyllin family (tetra- to hepta -peptides all containing the residues Pro and Trp ), and (ii) the rubellidinins ( pentapeptides all containing two Phe residues at positions 3 and 4). To ate, no biological activity has been found for any of these peptides, but it is suspected that the tryptophyllins may be neurotransmitters or neuromodulators.