bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal Structure of Methyl[tetrakis(pyrazol-1-yl)borato-N,N']mercury(II)
Authors: Canty AJ , Skelton BW , White AH
Published: September 2010

Crystals of methyl[tetrakis(pyrazol-l-yl)borato-N,N']mercury(II) [MeHg(B(pz)4}] are triclinic, Pi, a 12.73(2), b 8.88(1), c 8.10(1) �, α 109.80(8), β 99.16(9), γ 103.05(10)�, Z 2. The structure, determined by single-crystal X-ray methods (R 0.12 for 1598
'observed' reflections), has molecules of MeHg(B(pz)4} with two pz groups coordinated to mercury, giving planar but irregular coordination. The more strongly bound group has Hg-N 2.07(4) A with C-Hg-N 169(2)�, and the other group has Hg-N 2.65(4)� with C-Hg-N 112(1)�.
New Naphthopyrone Pigments From the Crinoid Comanthus parvicirrus
Authors: Sakuma Y , Tanaka JI , Higa T
Published: September 2010

Two new naphthopyrones, 5,10-dihydroxy-8-methoxy-2-propyl-4H-naphtho[1,2-blpyran-4-one(4) and 5,8-dihydroxy-6,10-dimethoxy-2-propyl-4H-naphtho[2,3-blpyran-4-one (5), have been isolated from the crinoid Comanthus parvicirrus.
The Structure of 1,1'-Oxalylbisisatin, a Reactive α-Oxo Imide
Authors: Black DS , Chaichit N , Gatehouse BM , Moss GI
Published: September 2010

The X-ray crystal structure determination of the reactive α-oxo imide 1,1'-oxalylbisisatin (1) is described. Bond length and bond angle details are compared with those of seven similar cyclic imide structures (2)-(8).
The Crystal and Molecular structure of trans-Dichlorobis(1,3-Diaminopropan-2-ol)cobalt(III) Chloride
Authors: Kivekas R , Sundberg MR
Published: September 2010

A single-crystal X-ray structure determination of the title compound is reported. The compound crystallizes in the space group P1 with a 7.273(1), b 8.525(2), c 12.358(3) �, α 80.03(3),β 75.38(2), γ 65.06(2)� and Z 2. The final R value for 3318 reflections was 0.041. The structure consists of two independent trans- dichlorobis (l,3-diaminopropan-2-ol)cobalt(III) cations and chloride ions interconnected by a hydrogen bonding network. The axial Co-Cl bonds in the pseudo-octahedral coordination sphere are shorter than those in the coordination sphere of the copper(II) analogue. The compression is clearly related to the simultaneous flattening of the rings.
The Synthesis of (R)-2',3'-Dihydroxypropyl 5-Deoxy-5-Dimethylarsinyl-β-D-Riboside, a Naturally Occurring Arsenic-Containing Carbohydrate
Authors: Mcadam DP , Perera AMA , Stick RV
Published: September 2010

The synthesis of the title compound, isolated from the brown kelp ( Ecklonia radiata ) or the giant clam (Tridacna maxima), is reported. Glycosidation of 1-O-acetyl-2,3,5-tri- O- benzoyl -β-D-ribose, either directly with (S)-1,2-di-O-benzylglycerol or via the derived orthoester with (S)-1,2-O-isopropylideneglycerol, led to two fully protected glycerol β-D- ribofuranosides. Subsequent chemical manipulations led to a common intermediate having a free hydroxy group at C5 of the D-ribose residue. Replacement of this hydroxy group by a chlorine atom allowed the introduction of the dimethylarsinyl group at C5 in a two-step procedure, and removal of protecting groups provided the natural product.
Photochemical Reactions of Aliphatic-Amines in Dichloromethane Solution
Authors: Errabalsells R , Frasca AR
Published: September 2010

Irradiation of aliphatic amines (primary, secondary and tertiary) in dichloromethane afforded amine hydrochlorides or N- chloromethyl derivatives, depending on the amine structure and the molar ratio of the solution. Some aspects of these phototransformations are discussed.
The Relationship Between Octahedral and Trigonal-Prismatic Coordination in Bis Tridentate Complexes of TiIV and VIV
Authors: Diamantis AA , Manikas M , Salam MA , Snow MR , Tiekink ERT
Published: September 2010

The crystal structures of two vanadium complexes V( aabh )2 (1) and V( aasalh )2 (2) and of two titanium complexes Ti( aabh )2 (3) and Ti( babh )2 (4), where aabh is the dinegative, tridentate ligand pentane-2,4-dione benzoylhydrazonato (2-), aasalh is pentane-2,4-dione salicyloylhydrazonato (2-) and babh is 4-phenylbutane-2,4-dione benzoylhydrazonato (2-), were determined by X-ray diffraction methods. Crystals of (1) are monoclinic, space group P21/c, a 8.906(3), b 11.840(2), c 22.450(6)Ǻ, β 97.72(3)°, V 2345.8 and Z 4; those of (2) are triclinic, space group Pī , a 9.802(4), b 10.205(3), c 13.688(6)Ǻ, α 100.56(3),β 94.07(4),γ 112.89(3)°, V 1224.6 Ǻ3 and Z 2; those of (3) are monoclinic, space group C2/c, a 18.543(4), b 10.269(4), c 12.589(4)Ǻ, β 106.80(2)°, V 2294.9 Ǻ3 and Z 4; and those of (4) are monoclinic, space group P21/n, a 10.923(4), b 19.139(3), c 14.610(5)Ǻ, β 94.54(3)°, V 3044.7 Ǻ3 and Z 4. The structures were refined by a full-matrix least-squares procedure in each case to final values of R 0.102, 0.044, 0.049 and 0.058 for the structures (1), (2), (3) and (4), respectively, and values of Rw 0.099, 0.049, 0.053 and 0.065 for 1735, 3405, 1185 and 2911 statistically significant reflections, respectively. In the vanadium complexes the coordination geometry is approximately trigonal prismatic, whereas in each of the titanium complexes the two tridentate ligands are in a meridional arrangement with an approximately octahedral coordination. The stabilization of vanadium(IV) in the absence of the oxo function and the role of the metals in producing different coordination geometries are discussed.
Cyclopentadienyl-Ruthenium and -Osmium Chemistry. XXXI. Preparation of Some Complexes Containing 1,1'-Bis(diphenylphosphino)ferrocene (dppf): X-Ray Structure of RuH(dppf)(η-C5H5)
Authors: Bruce MI , Butler IR , Cullen WR , Koutsantonis GA , Snow MR , Tiekink ERT
Published: September 2010

Exchange of 2PPh3 for Fe(η-C5H4PPh2)2 ( dppf ) in RuCl (PPh3)2(η-C5H5) (80°C, 16 h) afforded RuCl ( dppf )(η-C5H5), which was converted into the corresponding hydride and 1,2-bis( methoxycarbonyl )vinyl derivatives. Crystals of RuH ( dppf )(η-C5H5) are triclinic, space group Pī with a 14.392(3), b 20.175(5), c 12.379(2)Ǻ, α 105.02(2),β 109.73(2),γ 96.56(2)° and Z 4. The structure was refined by a blocked-matrix least-squares procedure to R 0.055 and Rw 0.056 for 3917 reflections with I ≥ 2.5σ(I).
The Cyclopropane-Mediated Ring-Expansion of [4.3.1]Propellenes. A New Route to [5.3.1]Propelladienes
Authors: Banwell MG
Published: September 2010

The [5.3.1] propelladiene (1) has been synthesized in six steps from the readily available [4.3.1] propellene (10a). Epoxidation of (10a) gives oxide (11a) which undergoes base-promoted rearrangement to allylic alcohol (12a). Simmons-Smith cyclopropanation of (12a) then gives the tetracyclic alcohol (13a). Mild thermolysis of the derived mesylate (14a) affords the ring-expanded isomer (20) which reacts with 1,8-diazabicyclo [5.4.0]undec-7-ene to give diene (1). A similar sequence of reactions has been used in the preparation of dienol (2) from acetal (10b). Compounds (1) and (2) react with 4-phenyl-4H-1,2,4-triazoline- 3,5-dione to give the Diels-Alder adducts (29a) and (29b) respectively.
Structural Characterization of Di-μ-hydroxo-bis[trichloro(tetrahydrofuran)tin(II)] Bis(tetrahydrofuran)
Authors: Chappell SD , Engelhardt LM , Raston CL , White AH
Published: September 2010

The title compound [( thf )Cl3Sn(OH)2SnCl3( thf )].2thf ( thf = tetrahydrofuran ) has been characterized by single-crystal X-ray structure determination, allowing comparison of its geometry with the recently recorded [( thf )BrCl2Sn(OH)2Cl2Br( thf )].2thf,1 with which it is isomorphous.
The Effect of Pressure on the Anation of Diaquabis(ethane-1,2-diamine)cobalt(III) by Selenate and Sulfate, and on the Isomerization of the trans-Aquabis(ethane-1,2-diamine)(hydrogenselenito)cobalt(III) Ion
Authors: Fowless AD , Lawrance GA , Stranks DR , Sullivan TR , Vanderhoek N
Published: September 2010

The reversible nucleophilic substitution of cis-[Co(en)2(OH2)2]3+ (en = ethane-1,2-diamine) by sulfate and selenate at pH 2.0 was studied at elevated pressure, and activation volumes (ΔV‡) for anation and solvolysis were determined. The ΔV‡ values for anation by sulfate and selenate were +8.3�0.5 and +8.5�0.4 cm3 mol-1 respectively, whereas solvolysis of sulfato and selenato complexes cis -[Co(en)2(OH2)(XO4)]+ gave ΔV‡ values of -2.2�0.4 and -3.3�0.7 cm3 mol-1 respectively. The trans → cis [Co(en)2(OH2)(OSeO2H)]2+ isomerization studied at pH 1.0 and elevated pressure yielded ΔV‡ + 7.2�0.4 cm3 mol-1. All reactions can be interpreted in terms of dissociative mechanisms.
The Crystal and Molecular-Structure of 4,7,13-Trioxa-1,10-diazacyclopentadecanepotassium(I) Thiocyanate
Authors: Abouhamdan A , Lincoln SF , Snow MR , Tiekink ERT
Published: September 2010

The crystal structure of
the title compound [K(-NHCH2CH2OCH2CH2OCH2CH2NHCH2CH2OCH2CH2-)(NCS)] has been determined. Potassium(I) is 1.41 Ǻ above the plane of the three oxygens of the 4,7,13-trioxa-1,10-diazacyclopentadecane ligand, and is seven-coordinated. Potassium(I) is 2.871(7), 2.798(7) and 2.772(7)Ǻ from the three oxygens, and 2.905(8) and 2.945(8)Ǻ from the two nitrogens of 4,7,13-trioxa-1,10-diazacyclopentadecane, 2.861(7)Ǻ from an oxygen of a second such ligand, and 2.809(8)Ǻ from the thiocyanate nitrogen. Crystals are monoclinic, space group P21/n with unit cell parameters a 8.015(4), b 14.755(4), c 13.744(4)Ǻ, β 95.37(3)°, and Z 4. The structure was solved by direct methods and refined by a full-matrix least-squares procedure to final R 0.089, Rw 0.099 for 981 reflections with I ≥ 2.5σ(I).
15N N.M.R. Study of Some Palladium(II) Ammine Complexes
Authors: Appleton TG , Hall JR , Ralph SF , Thompson CSM
Published: September 2010

Palladium(II) ammine complexes enriched in 15N give sharp singlets in their 15N n.m.r . spectra. The 15N chemical shifts depend primarily on the trans donor atom, in a qualitatively similar way to those for platinum(II) ammine complexes. A dimethylformamide solution of Pd(NH3)2Cl2 prepared in the usual way gave a single peak, consistent with the presence of only one isomer (trans). Reactions of increasing amounts of aqueous perchloric acid with Pd(NH3)42+ allowed peaks to be identified for Pd(NH3)3(H2O)2+, cis -Pd(NH3)2(H2O)22+ and Pd(NH3)(H2O)32+. The initial product of the reaction of trans-Pd(NH3)2Cl2 with silver ion is trans-Pd(NH3)2(H2O)22+, which rapidly disproportionates to Pd(NH3)3(H2O)2+ and Pd(NH3)(H2O)32+. With standing, subsequent reactions ultimately produce a solution containing predominantly cis -Pd(NH3)2(H2O)22+ in equilibrium with small amounts of the tri- and mono-ammine complexes, and free ammonia.
Preparations, Magnetic Susceptibility and Structural Studies of Trinuclear Copper(II) Compounds of 4,4,9,9-Tetramethyl-5,8-diazadodecane-2,11-diol
Authors: Curtis NF , Gainsford GJ , Morgan KR
Published: September 2010

Reduction of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione yields the meso and racemo isomers of 4,4,9,9-tetramethyl-5,8-diazadodecane- 2,11-diol which form trinuclear compounds [Cu3( amat )2](ClO4)2 with all ligand alcohol groups deprotonated . The structure of the compound of the racemo amino alcohol has been determined by X-ray diffractometry [space group, P21/c, a 1594.5(4), b 1786.0(5), c 1419.1(4) pm, β 104.84(2)°, R 0.040, Rw 0.049 for 3466 reflections]. The cation has three copper(II) ions close to colinear (Cu-Cu 294 pm, Cu-Cu-Cu 177°), with the terminal copper(II) ions coordinated by the two nitrogen and two oxygen atoms of the tetradentate diamine-diolato ligand, and the central copper(II) ion by the oxygen atoms of the two ligands . All copper(II) ions have coordination environments intermediate between square planar and tetrahedral, the distortion from square planar being greater for the central ion [angle between planes O2Cu,CuO2 is 45°, compared with 16° between the planes N2Cu,CuO2 of the terminal copper(II) ions]. The magnetic susceptibilities of the compounds, measured over the temperature ranges 96-269 and 99-360 K for the racemo and meso isomers, respectively, are similar. Calculated effective magnetic moments/copper atom range from 1.07 μB at 99 K to 1.28 μB at 360 K. The susceptibility values were fitted to the expression for three spin-coupled copper(II) ions, with resultant spin coupling parameters, J, between adjacent atoms of -212 cm-1 ( meso-amat )and -230 cm-1 (racemo-amat ).
Coordination of 2,2'-Bithiazole. Spectral, Magnetic and Structural Studies of the Iron(II) and Nickel(II) Complexes
Authors: Craig DC , Goodwin HA , Onggo D , Rae AD
Published: September 2010

Iron(II) and nickel(II) complexes of 2,2′bithiazole (2bt) have been prepared. Salts of [Fe(2bt)3]2+ have spectral properties typical of iron(II) diimine systems. Their magnetic and Mossbauer spectral properties show an anomalous temperature-dependence which is associated with a temperature-induced singlet (1A1) ↔ quintet (5T2) transition. The manifestation of the spin transition is complicated by the existence of two modifications of the complex perchlorate. In one of these there is a relatively small fraction of quintet state species in an essentially low-spin lattice. This fraction increases only slightly at elevated temperatures within the range 89-343 K. The other modification is essentially high-spin at high temperatures and low-spin at low temperatures. The quadrupole splitting values for the two high-spin species are quite different, arising from different lattice contributions. The structures of 2bt and the related 4,4′-bithiazole and of [Ni(2bt)3][ClO4]2 have been determined by single-crystal X-ray diffactometry. These afford a comparison of the coordination features of the isomeric bithiazoles. 2,2′-Bithiazole, orthorhombic with space group P bca , Z = 8, α 9.284(1), b 14.564(1), c 10.802(1) Ǻ; 4,4′-Bithiazole, monoclinic with space group P21/c, Z = 2, a 5.528(2), b 6.288(2), c 11.316(4)Ǻ. The nickel complex, orthorhombic with non-centrosymmetric space group Pna21, four molecules per unit cell, a 16.709(3), b 9.511(4), c 17.491(2)Ǻ, has a stacking fault which reduces the intensity of h = 2n+1 data. Pseudosymmetry enables data with h = 2n to be described by a disordered structure in the centrosymmetric space group Pnmn.
Pyrolysis of Aryl Azides. IX. Azomethines as Weak Neighboring Groups
Authors: Dyall LK , Holmes AL
Published: September 2010

The following rates of pyrolysis (relative to azidobenzene at 120°) have been measured in decalin solution: 2-azidobenzaldehyde, 28.8; 2-azidobenzylideneaniline, 59.5; 2-azidobenzaldehyde phenylhydrazone, 8.9; 2-azidobenzaldehyde oxime O-methyl ether, 1.3;2-azidoacetophenone oxime O-methyl ether, 23.4; 2-azidobenzophenone phenylhydrazone, 9.7. It is argued that these relative rates are largely determined by the extent to which the ortho substituent is in the reactive conformation for an electrocyclic process. Indazoles substituted on N2 are isolated from pyrolysis of those azides with ortho-azomethine substituents.
Palladium-Catalyzed Coupling of Naphthyl Triflates With Organostannanes
Authors: Crisp GT , Papadopoulos S
Published: September 2010

Naphthyl triflates undergo a palladium- catalysed coupling with organostannanes to give substituted naphthalenes.
Enthalpies of Mixing of Multicomponent Alkane Mixtures
Authors: Brady TJ , Weiguo S , Williamson AG
Published: September 2010

Enthalpies of mixing are reported for ternary n-alkane mixtures prepared from binary mixtures with large chain-length differences and at temperatures where the enthalpies of mixing of simple binary mixtures show changes of sign. In neither case does the behaviour of the ternary mixtures deviate significantly from that of the congruent binaries.
Confirmation of the Absolute Stereochemistry of Hispidol-B [(3S,23R,24S)-Tirucall-7-ene-3,23,24,25-tetrol]
Authors: Bhandari P , Chaichit N , Gray AI , Skelton BW , Waterman PG , White AH
Published: September 2010

The stereochemistry of hispidol-B has been confirmed as (3S,23R,24S)- tirucall-7-ene-3,23,24,25-tetrol by means of a single-crystal X-ray diffraction study.
Revised Absolute Configurations of Latifolic Acid and the Pyrrolizidine Alkaloid Latifoline
Authors: Roitman JN , Wong RY
Published: September 2010

The absolute stereochemistry of (+)- latifolk acid has been determined by single-crystal X-ray crystallographic analysis to be (2S,3R,4R)-3- hydroxy-2,4-dimethyl-5-oxotetrahydrofuran-3-carboxylic acid. The configuration of the three chiral centres is opposite to that presently recorded in the literature. Accordingly, the configuration of the pyrrolizidine alkaloid, latifoline, which includes a latifolic acid side chain, must be revised.
Lewis-Base Adducts of Main Group-1 Metal-Compounds. IX. Synthesis and Structural Characterization of Adducts of the Lithium(1) Halides With N,N,N',N'-Tetramethylethylenediamine
Authors: Raston CL , Skelton BW , Whitaker CR , White AH
Published: September 2010

Crystalline adducts of the
lithium(I) halides, LiX (X = Cl , Br, I) with N,N,N′,N′- tetramethylethyl-enediamine (tmeda) have been synthesized and characterized by single-crystal X-ray studies. Both bromide and iodide form 1 : 1 adducts which are μ,μ-dihalo-bridged binuclear species, [( tmeda )LiX2Li( tmeda )], with four-coordinate N2LiX2 lithium environments; in addition, the iodide yields an ionic 1 : 2 adduct, [Li( tmeda )2]+I-. The chloride complex is a novel 3 : 2 polymer based an a double cubane Li6Cl6 unit solvated by chelating and bridging tmeda units.
Electrochemical Reduction of Aromatic Ketones in N,N-Dimethylformamide Containing Benzoic Acid. Effect of the Basicity of the Carbonyl Group
Authors: Kwiatek B , Kalinowski MK
Published: September 2010

The effect of benzoic acid on the polarographic reduction of a series of aromatic ketones in N,N- dimethylformamide has been investigated. In the presence of this acid a new cathodic wave (pre-wave) appears at more positive potentials than the original (orig.) wave of the reactant. A linear correlation has been found between ΔE½ and the pKBH+ values, where ΔE½ = E½ pre.wave -E½orig.wave and pKBH+ stands for the negative logarithm of the acidity constant of the protonated ketone . It is concluded that the pre-wave is associated with the cathodic reduction of a hydrogen-bonded adduct of 1 : 1 type formed between the carbonyl compound and the acid in the double layer. The effect of the double layer on the basicity of the ketones is discussed.
Cobalt, Iron and Ruthenium Complexes of Picolinic and Dipicolinic Acids: Syntheses, Solution Properties and Kinetics of Electron Transfer Reactions With Cytochrome C(II) and Some Inorganic Reductants
Authors: Ellis RM , Quilligan JD , Williams NH , Yandell JK
Published: September 2010

Tris picolinate complexes of CO111 and RU111 have been synthesized, and their standard potentials measured (432 �10, 403 �2 mV) at 25�C and ionic strength 0.1 mol dm-3. The self-exchange rate constant of Ru ( pic )3O/- was found to be (1 .4 �0.9)×108 dm3 mol-1 s-l, from reaction with cytochrome C(II), Co( bpy )32+ and ~Co( phen )32+. For the reaction between Fe( dipic )2- and cytochrome ~(II), at 2S260C, pH 5.5 and I 0.1 mol dm-3 (KNO3), the second-order rate constant was (3.2 �0.l)×105 dm3 mol-1 s-1,with ΔH+ 19.9 �0.9 kJ mol-1 and ΔS+ -72.8 �.7 J K-1 mol-l. The self-exchange rate constant of Fe( dipic )2-/2- was reevaluated as (5.8 �0.2)×106 dm3 mol-l s-1.
The Lead Dioxide Anode. I. A Kinetic Study of the Electrolytic Oxidation of Cerium(III) and Manganese(II) in Sulfuric Acid at the Lead Dioxide Electrode
Authors: Randle TH , Kuhn AT
Published: September 2010

The electrolytic oxidation
reactions of cerium(III) and manganeseII) in sulfuric acid have been used as probes to investigate the mechanism of the lead dioxide anode. The kinetics observed for such reactions at the lead dioxide surface provide no direct support for the proposal that the lead dioxide anode functions by a sequential 'two-step' mechanism (heterogeneous chemical oxidation of solution species followed by electrochemical oxidation of the reduced lead dioxide surface); rather the kinetics show characteristics similar to those observed previously for the oxidation of cerium(III) and manganese(II) at the platinum electrode, suggesting that the lead dioxide surface functions as a simple, 'inert' electron-transfer agent.
Caveat Regarding the Use of Substituent Parameters in Statistical Analyses of Molecular Properties. I. The Interdependence of Field, Resonance, Electronegativity and Polarizability Effects
Authors: Cook IB , Sadek M , Ternai B
Published: September 2010

lt is shown that several frequently employed electronegativity ( α1), field ( σF) and resonance ( σR) parameters are substantially interdependent for most of the commonly used substituents. Substituents are shown to belong to two categories, In which the first atom of the group is a first row (FR) or non-first row (NFR) atom, The degree, of interdependence of the three parameters increases markedly when the two substituent types are treated separately, although it is found that, for NFR
groups, σF and σx alone are highly correlated, in contrast to FR groups, where σR contributes significantly to the interdependence equations. The disparate behaviour of FR and NFR substituent types is partly reconciled by the inclusion of a polarizability parameter (σx). Evidence is presented which indicates that σF is the parameter which is constitutionally dependent on the other three, although the dependence seems not to be completely causative, but partially fortuitous. Implications for the quantitative analysis of molecular processes at positions close to the substituent where electronegativity and polarizability effects are believed to operate, are discussed.
Structure of a New Dolastane Diterpene From Dictyota furcellata
Authors: Dunlop RW , Ghisalberti EL , Jefferies PR , Skelton BW , White AH
Published: September 2010

The structure and relative stereochemistry of a new dolastane diterpene isolated from the brown alga Dictyota furcellata has been determined from spectral evidence and an X-ray diffraction study. Crystals are monoclinic, P21, a 15.762(5), b 15 562(5), c 9.599(6) � , β 100.05(4)° Z 4; R was 0.065 for 3587 'observed' reflections. If the dolastane absolute configuration is assumed, the compound is shown to be (6S,7R,14S)-6,7-diacetoxydolasta-l(15),8-dien-14-ol (1).
Self-Reactions of 1,3-Diphenylpropyl and 1,3,5-Triphenylpentyl Radicals: Models for Termination in Styrene Polymerization
Authors: Schreck VA , Serelis AK , Solomon DH
Published: September 2010

Quantitative determination of the products from thermal decomposition of 1,1?,3,3'- tetraphenylazopropane (2) and 1,1',3,3',5,5?-hexaphenylazopentane (5) shows that the respective derived title radicals (1) and (4) undergo self-reactions with a similar preference for combination over disproportionation. The proportion of combination increases from 86 to 93% ( E+c-E+d = 9.6 � 1.2 kJ mol-1 and ΔSc+:- Δ Sd + : =43 �7 JK-1 mol-l) for (1), and from 86 to 93% ( E+c-E+d = 10.6 � 1.4 kJ mol-1 and ΔSc- Δ Sd : = 45 � 6 J K-1 mol-1) for (4) over the temperature range 80-161°. The relevance of these results to the termination mechanism in the radical polymerization of styrene is discussed. Some minor by-products (28)-(30) which arise by addition of 1,3-diphenylpropyl (1) to 1,3-diphenylpropene (14)/(15) have also been detected. The syntheses of the azo compounds (2) and (5), the former as separate, pure meso - and rac-diastereomers (2m) and (2r), and of their various expected decomposition products are described.
Preparations of 2,4-Disubstituted Oestradiols
Authors: Pert DJ , Ridley DD
Published: September 2010

2,4-Dibromoestra-1,3,S(10)-triene-3,17 β- diol
3-(2'-hydroxyethyl) ether (8) undergoes reaction with copper(11) chloride/sodium methoxide to afford a 4-bromo [2,3]- dioxan derivative (9) as the major product together with a minor amount of a 2-bromo [3,4]- dioxan derivative (10). These compounds were used to prepare a number of 2,4-disubstituted oestradiol derivatives. � Alternative routes to other 2,4-disubstituted oestradiols are described.
A Simple Preparation of Bis(η-cyclopentadienyl)hydrido-(halogeno)tungsten(IV) Complexes
Authors: Bennett MA , Schwemlein HP
Published: September 2010

The monohydrido complexes WHX( ή-C5H5)2 (X = CI, Br, I) have been isolated from the reaction of WH2(η-C5H5)2 with, respectively, carbon tetrachloride, bromoform, and methyl iodide.
Potential GABAB Receptor Antagonists. III. Folded Baclofen Analogs Based on Phthalide
Authors: Donati C , Prager RH , Weber B
Published: September 2010

Possible analogues of baclofen, 3-aminomethyl-5-chloro-, 3-aminomethyl-6-chloro- and 3-aminomethyl-5,6-dichloro-isobenzofuran-1(3H)-one, have been prepared for evaluation as antispasticity agents. The corresponding 3-hydroxyisobenzofuran-l(3H)-one was reacted with ethyl acetoacetate under acidic conditions, and the keto ester hydrolysed and decarboxylated to give the 3-(2-oxopropyl)isobenzofuran-l(3H)-one; this was treated with hydrazoic acid, and the product was hydrolysed. A parallel series of (3-oxo-1,3-dihydroisobenzofuran-1-y1)glycines was obtained by treating the keto ester first with hydrazoic acid, and hydrolysis of the resulting acetamides.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LII. Synthesis and Structural Characterization of Mononuclear Chloro- and Bromo-pyridinebis-(triphenylphosphine)silver(I) Complexes
Authors: Engelhardt LM , Healy PC , Kildea JD , White AH
Published: September 2010

The mononuclear adducts chloro - and bromo-pyridinebis (triphenylphosphine)silver have been synthesized and structurally characterized by single-crystal X-ray diffraction methods. The two complexes are isomorphous, monoclinic, space group P21 or P21/m, a ≈ 9.8, b ≈ 20.0, c ≈ 9.1 � , β ≈ 97.5�, Z 2; in space group P21/m, they were refined to residuals of 0.038, 0.036 for 2392, 2157 'observed' reflections respectively. No comparable iodide adduct has been isolated. In both structures the silver atom is four-coordinate; Ag-Cl,Br are 2.511(2), 2.629(1) �; Ag-P, 2.472(1), 2.476(1) �, and Ag-N, 2.585(5), 2.570(5) � respectively, the Ag-N distance being longer than Ag-P, indicating very weak coordination of the pyridine.
Preparation of Carboxylate Esters of Polyhydric Alcohols by Using a Sulfonated Charcoal Catalyst
Authors: Prager RH , Yurui Z
Published: September 2010

Ethane-1,2-diol,
propane-1,2-diol, butane-1,4-diol and propane-1,2,3-triol are readily esterified by carboxylic acids in near quantitative yields in the presence of a sulfonated charcoal catalyst.
Comparison of Theoretical and Experimental Determinations of cis/trans Proline Isomer Ratios: Effect of Molecular Charge State
Authors: Bremer J , Mendz GL
Published: September 2010

The resonances of the 1H and 13C n.m.r. spectra of the peptide
Pro-Pro-Pro in aqueous solutions have been assigned to specific nuclei by
employing one- and two-dimensional techniques and pH titrations. Minimum energy
conformations of the tripeptide in different
ionization states were estimated by conformational energy calculations with two
effective dielectric constants. The cis/trans isomer
ratios of the lowest energy conformers obtained for each set of conditions were
compared to the isomer ratios measured from the 13C n.m.r. spectra of the
peptide in the cationic, zwitterionic and anionic
forms. The theoretical predictions did not agree with the experimental data.
The conformations and geometry of triprolyl sequences
in the uncharged pentapeptide Ac- Gly-Pro-Pro-Pro-Gly-NHMe
were investigated for different isomer configurations of the proline residues. The structure of the molecule was
characterized by its conformational energy and by two other parameters
estimated from the atomic coordinates of each conformation: the distance
between atoms located at the end groups, and the direction cosine between
vectors defined at the N- and C-terminal ends of the molecule. About 90% of the
statistical weight of the lowest energy conformers corresponded to extended geometries
of the triprolyl sequence.
Synthesis, Characterization and Enhanced Cleavage of Diphosphate and Triphosphate Bound to Tetraaminecobalt(III) Centers. Crystal Structure of [N,N-Bis(2-aminoethyl)ethane-1,2-diamine](diphosphato)cobalt(III) Perchlorate Monohydrate
Authors: Engelhardt LM , Keegan EA , Lawrance GA , White AH
Published: September 2010

The complexes [Co( tren )(P2O7H2)] (ClO4).H2O, [Co( tren )(P3010H3)] (ClO4) (tren = N,N-bis(2- aminoethyl )ethane-1,2-diamine) and [Co( cyclen )(P2O7H2)](ClO4)(cyclen = 1,4,7,10-tetraazacy-clododecane ) have been prepared and characterized. The complex [Co( tren )(P207H2)](C104).H20 crystallized in the monoclinic space group P21/n,a 10.655(3), b 14.675(5), c 11.260(4) � , β 98.49(3) for a single-crystal structure determination R was 0.041 for 4043 'observed' reflections. Despite the presence of a primary and a tertiary nitrogen donor in the plane of the cobalt and the phosphate oxygen donors, bond distances to Co-N(primary) and Co-N(tertiary) at 1.926(3) and 1.924(3) � respectively are equivalent, as are the Co-O distances of 1.940(2) and 1 .943(3) to the N(primary) and N(tertiary) respectively. Axial Co-N(primary) bonds (av. 1.952 A) are elongated compared with the in-plane N(primary), and the axial N-Co-N angle is distorted (171.6�). The hydrolysis of the diphosphate and triphosphate complexes at pH 7.3 in the presence of an assisting complex, [Co( tn )2(OH2)(OH)]2+ ( tn = propane-1,3-diamine) or [Co( tren )(OH2)(0H)]2+, was followed by 31P n.m.r. spectroscopy, and rate enhancements of up to about 104 compared with free polyphosphate were observed, with the diphosphato complexes being least sensitive to cleavage by added complex. Intermediates in which the polyphosphate bridges two metal centres are apparently involved; the inability of [Pd(en)(0H2)2]2+(en= 1,2-ethanediamine) to enhance cleavage is consistent with this, since this ion does not form complexes with polyphosphates. [Co( tren )(ATP)](ATP=adenosine triphosphate ) was also prepared but not isolated; assisted hydrolysis with [Co( tren )(OH2)(OH)]2+ is about 104 faster than unassisted hydrolysis of free ATP under similar conditions.
The Crystal and Molecular Structure of the Trinuclear Complex Bis[(μ-S)-α,α′-{(2-mercapto-5-methylbenzene-1,3-diyl)di(methylidyne)di(azino)}bis(cyclohexane-methanol)ato(3-)]tripalladium(II), L2Pd3. A New Coordination Mode for the Robson-Type Ligand L3-
Authors: Hoskins BF , Mcdonald IAS
Published: September 2010

The crystal and molecular structure of the trinuclear complex L2Pd3 has been determined by single-crystal X-ray diffraction techniques at room temperatures, 20°C. The quinquedentate binucleating ligand, L3-, is formally the trianion α,α′-[(2-mercapto-5-methylbenzene-1,3-diyl )di(methylidyne)di(azino)]bis(cyclohexaemethano)ato(3-). Crystals of L2Pd3 are triclinic, PI, with a 11.896(1), b 13.4103(7), c 17.451(3) � , α 75.66(1), β 79.93(1) and γ88.99(1)�, Z 2. The structure was solved by the normal Fourier methods and refined by a least-squares procedure which gave final R and R, values of 0.046 and 0.049 respectively for the 7769 statistically significant reflections. The approximately square-planar coordination environments of the palladium centres give rise to a boat-shaped arrangement in which an approximate, non-crystallographic, twofold axis normal to the plane of the central metal is evident. The notable feature of the structure lies in the novel coordination mode adopted by the binucleating ligand. With respect to the binuclear complexes of this ligand, an electronic reorganization has occurred in one of the sidearms of both ligands which enables the formation of the pair of hydrazine bridges and also causes two of the terminal oxygen groups to become non-coordinating.
Studies of the Determination of Fluoride in Vegetation Samples
Authors: Cattrall RW , Chek WL , Hamilton IC , Watkins PJ
Published: September 2010

The use of the Association of Official Analytical Chemists (AOAC) First Action method, which is based on acid leaching of the dried, ground sample, is examined for its suitability for the recovery of fluoride from leaf material derived predominantly from indigenous Australian trees. The method is compared with two independent but time-consuming procedures based on oxygen pyrolysis and pyrohydrolysis. These two reference methods give internally consistent results and provide a sound basis on which to critically examine the AOAC First Action method. It is concluded that the AOAC method, in general, gives reliable and rapid results, although two of the species studied showed a low fluoride recovery. The AOAC method uses a fluoride electrode finish which is slow for solutions of low concentration. A graphical procedure is examined for estimating the steady-state electrode potential; this procedure increases the speed of the analysis without affecting unduly the accuracy of the analysis.
The Identification and Synthesis of Further Lichen β-Orcinol para-Depsides
Authors: Elix JA , Chester DO , Gaul KL , Parker JL , Wardlaw JH
Published: September 2010

The new lichen depsides, methyl 5-chloronorobtusatate (4) and 4-O-demethyldiffractaic acid (5), have been detected in an Erioderma sp. And Xanthoparmelia duplicata Hale respectively, and the structures confirmed by total synthesis. In addition, the lichen depsides, 2'-O- methylatranorin (1), 2-O-methylsquamatic acid (2) and elatinic acid (3), have been prepared by unambiguous synthesis for the first time.
Thienoisothiazoles. III. The Synthesis and Reactions of 3-Phenyl-5-alkylthioisothiazole-4-carbonitriles and 3-Phenylthieno[3,2-d]isothiazoles
Authors: Krebs HD
Published: September 2010

Oxidation of the alkyl 3-amino-4-cyano-3-phenylpropenedithioates (1), obtained by alkylation of the condensation product of 3-amino-3-phenylpropenenitrile and carbon disulfide, produced 3-phenyl-5-alkylthioisothiazole-4-carbonitriles (2a-d). The ease of nucleophilic displacement of the S-alkyl group in the isothiazole (2a) was utilized to synthesize the isothiazoles (2f-j). 3-Phenylthieno[3,2-d] isothiazole (3e) was prepared by deamination, hydrolysis and decarboxylation of the intermediate ethyl 4-amino-3-phenylthieno[3,2-d]isothiazole-5-carboxylate (3a), which was obtained by ring-closure of ethyl 2-(4-cyano-3-phenylisothiazol-5-ylthio)acetate (2d). 3-Phenylthieno[3,2-d] isothiazole was unreactive towards weaker electrophiles , but undergoes bromination and nitration in the α-position of the thiophen ring. The position of substituents in 5-bromo- (3w) and 5-nitro-3-phenylthieno[3,2-d] isothiazole (4a) was verified by alternative synthesis. The attempted deamination of 4-amino-5-bromo-3-phenylthieno[3,2-d] isothiazoe (30) and 4-amino-S-nitro-3-phenylthieno[3,2-d] isothiazole (3r) yielded 3-phenyl-S-nitrothieno[3,2-d]isothiazol-4-ol (3s) only, but the isomeric 4-bromo-3-phenyithieno[3,2-d] isothiazole (3v) was obtained by decarboxylation of 4-bromo-3-phenylthieno[3,2-d]isothiazole-5-carboxylic acid (3u). An alternative synthesis of the 5-nitro derivative was achieved by decarboxylation of 5-nitro-3-phenylthieno[3,2-d]isothiazole-4-carboxylic acid (32). Mild reduction of 3-phenylthieno[3,2-dlisothiazole derivatives, (3a,b) and (4c), with hydrogen sulfide or hypophosphorous acid afforded the substituted 3-(α-aminobenzylidene )-2,3-dihydrothiophen-2-thiones (5a-c), and the 3-benzoyl-2-alkylthiothiophen derivatives (6a,b) were obtained by a one-step synthesis, which avoided the isolation of the air-sensitive intermediates.
The Selective Photocatalytic Oxidation of m-Phenoxytoluene on Titanium Dioxide Particles Supported in Nafion Membranes
Authors: Lund EA , Blatt E , Furlong DN , Mau AWH , Sasse WHF
Published: September 2010

The selective photocatalytic oxidation of m-phenoxytoluene to m-phenoxybenzaldehyde on titanium dioxide (TiO2) particles incorporated in Nafion membranes has been investigated. No more than 0.1% of by-products was detected after 24 h irradiation, and the catalytic nature of the reaction is demonstrated with a turnover in excess of 100. In addition, a yield of at least 28% is achieved. Both the emission characteristics and catalytic activity of TiO2 are regenerated by washing the membrane in butanol.
Novel Conformational Isomerism in a Six-Coordinate Silver(I) Complex of a Sexadentate Macrocycle With an N3S3 Donor Set
Authors: Silong SB , Kildea JD , White AH
Published: September 2010

The synthesis and structural characterization of the condensation product formed by a template reaction of 2,6-diacetylpyridine and 3,6,9-trithiaundecane-1,11-diamine about silver(I) (as perchlorate ) are described. Crystals are monoclinic, C2/c, a 27.114(10), b 7.546(5), c 22.137(10) �, β 105.35(3)°, Z= 8×[AgL]+(ClO4)-(L = C17H25N3S3). R was 0.057 for 2372 'observed' reflections. The six-coordinate silver(I) atom lies in a novel environment comprised of a mer-triaza moiety derived from 2,6-diacetylpyridine [Ag-N, 2.422(8) (central), 2. 538(8), 2.546(9)� (distal)] and a fac-trithia moiety straddling its plane [Ag-S, 2.603(6) (central), 2.815(4), 2.881(3) � (distal)]. The complex cation is a different conformational isomer to that found in the previously studied tetraphenylborate salt. In the latter, Ag-N are 2.422(9) (central), 2.613(9), 2.399(7) � (distal), with Ag-S 2.670(3) (central), 2.655(3), 2.949(4) � (alstal).
Enolic Ortho Esters. II. Tandem Nucleophilic Electrophilic Dimethylation of 4',4'-Dimethyl-3,4,5,8-tetrahydrospiro[2H-1-Benzopyran-2,2'-[1,3]dioxolan]
Authors: Collins DJ , Rutschmann SB
Published: September 2010

Reaction of 4′,4′-dimethyl-3,4,5,8-tetrahydrospiro[2H-1-benzopyran-2,2′-[l,3]dioxolan](9) with methylmagnesium iodide in benzene or toluene at 40� gave the iodomagnesium enolate acetal (10) which upon in situ reaction with methyl iodide afforded 56% of pure 6 ξ-methyl- 6-[2′-(2″,4″,4″-trimethyl-1″,3″-dioxolan 2″yl)ethyl]cyclohex-3-en-one (11), the product of tandem nucleophilic/electrophilic dimethylation . Aqueous ammonium chloride workup of the iodomagnesium enolate
(10) gave 6-[2′-(2″,4″,4″-trimethyl-1″,3″-dioxolan 2″yl)ethyl] cyclohex-3-en-1-one (7). Some further transformations of the methylated keto acetal (11) are described.
15N-Labeling Study of the Rearrangement of r-2,4-Dichloro-t-6-hydroxy-3,6-dimethyl-2,T-5-dinitrocyclohex-3-enone to 4-Chloro-c-6-hydroxy-3,6-dimethyl-r-5-nitro-cyclohex-3-ene-1,2-dione
Authors: Hartshorn MP , Robinson WT , Wright GJ , Cheng LY
Published: September 2010

Reaction of hydroxy dinitro ketone (15) in solution gives the α-diketone (16). This reaction has been shown, by means of 15N n.m.r. spectroscopy, to occur via C2-epimeric nitro nitrites (19) and (20). X-Ray crystal analyses are reported for hydroxy dinitro ketone (15) and α-diketone (16).
Ab initio Studies on Hydrazines: 4H-1,2,4-Triazol-4-amine
Authors: Riggs NV
Published: September 2010

The geometries of four stationary structures of 4H-1,2,4-triazol-4-amine have been optimized with the 3-21g and 3-21g(N*) basis sets. The lowest-energy and only equilibrium structure predicted by these calculations is the 'perpendicular' CS form (7). All its calculated vibrational frequencies are real and, after zero-point vibrational-energy corrections, it lies 26.9 kJ mol-1 below the 'parallel' C, structure (6), here characterized as the transition structure for internal rotation about the N-NH2 bond (cf. 26.5 kJ mol-1 for the corresponding structures of 1H-pyrrol-1-amine, but only 8.7 kJ mol-1 for the corresponding structures of 2H-1,2,3-triazol-2-amine). The transition structure for inversion at the NH2 centre is, as for 1H-pyrrol-1-amine and 2H-1,2,3-triazol-2-amine, the perpendicular C2v � structure (5), the barrier being 21.4 kJ mol-1 (cf. 24-26 kJ mol-1 for the two reference azolamines ). The planar C2v structure (4) is a second-order saddle point lying 66.6 kJ mol-1 above the equilibrium structure (cf. 69.4 kJ mol-1 for 1H-pyrrol-1-amine, but only 41 .7 kJ mol-1 for 2H-1,2,3-triazol-2-amine). The calculated NH-stretching vibrational frequencies for 4H-1,2,4-triazol-4-amine are c. 20 cm-1 higher than those of 1H-pyrrol-1-amine and their splitting is c. 8 cm-1 greater but they show a very similar relative-intensity pattern, quite unlike that calculated for 2H-1,2,3-triazol-2-amine. ′
Eigenanalysis of the Coupled First-Order Isomerization Reactions of the Bis[(S)-alaninato]dinitrocobaltate(III) Ion
Authors: Beattie JK , Celap MB , Kelso MT , Nesic SM
Published: September 2010

Three of the five possible geometric isomers of the bis[(S)-alaninato] dinitrocobaltate (III) ion isomerize to the stable fourth isomer by a series of first-order reactions. The fifth isomer is not observed. The kinetics of the isomerizations in neutral, aqueous solutions between 65 and 95 C have been studied by chromatographic separation of the isomers. The data were fitted by eigenanalysis of the coupled first-order differential equations. The results are consistent with a reaction scheme requiring five rate constants, kxy, where xy represents isomerization from isomer x to isomer y. lsomer A is the Λ-(-)589-cis-NO2/cis-N/cis-O complex; isomer B the trans-NO2/cis-N/cis-O complex; isomer C the trans-NO2/trans-N/trans-O complex; and isomer D is the mixture of both diastereomers of the cis-NO2/trans-N/cis-O complex that is formed from B and C. The rate constants required are kAB, kbc , kBD , kCB and kCD . The same reaction scheme had been found previously for the analogous glycinato complexes, but the activation energies differ. For the valine and leucine analogues, the rate constants and activation enthalpies for the first isomerization reaction, represented by kAB, are similar to that of the alanine complex.
Imidazo[1,2-b]Pyridazines. VIII. Syntheses and Central Nervous System Activities of Some 6-Benzylamino (and methoxybenzylamino)-3-methoxy-2-phenyl(Substituted phenyl or pyridinyl)imidazo[1,2-b]pyridazines
Authors: Barlin GB , Davies LP , Ngu MML
Published: September 2010

Syntheses and IC50 values for the displacement of 3H-diazepam from rat brain plasma membrane are reported for a series of 6-benzylamino(and methoxybenzylamino )-3-methoxy-2-phenyl(substituted phenyl and pyridinyl )imidazo[l,2-b]pyridazines (and their 6-anilino and 6-phenethylamino analogues). The results are compared with those reported previously (by us) for the 6-chloro, 6-phenoxy, 6-benzylthio, and 6-benzyloxy compounds. In the imidazo[l,2-b]pyridazine ring system, 6-(o- and m- methoxybenzylamino ) groups were found to be beneficial to binding activity; eight compounds have been prepared with IC50 values less than 2 nM (cf. 3H-diazepam with IC50 of 4.2 nM ).2-(p-Aminopheny1)-3-methoxy- 6-(m- methoxybenzylamino )imidazo[1,2-b]pyridazine exhibited the highest activity with IC50 1.0 nM.
Aprotic Conjugate Addition Reactions of Lithiated Allylic Sulfoxides With Acyclic Enones; a Breakdown of the trans-Decalyl Transition State
Authors: Haynes RK , Katsifis AG , King LM , Vonwiller SC
Published: September 2010

The reactions of lithiated 1-(t-butylsulfinyl)prop-2-ene, 1-(t-butylsulfinyl)-3-methylbut-2-ene, 1-(t-butylsulfinyl)but-2-ene, 1-(phenylsulfinyl)but-2-ene and 2-methyl-1-(phenylsu1finyl)prop- 2-ene with methyl vinyl ketone, mesityl oxide and crotonaldehyde give largely carbonyl addition products arising from reaction through C1 or C3 of the allyl system. In the case of methyl crotonate, conjugate addition through C3 is observed. The initially formed diastereomers of the C1 adducts, allylic sulfoxides, are configurationally unstable. Only the lithiated 1-(t-butylsulfinyl)-3-methylbut-2-ene undergoes conjugate addition with methyl vinyl ketone to give an (E)-vinyl sulfoxide whose formation may involve the trans-decalyl transition state characteristic of the reactions of lithiated allylic sulfoxides with cyclic enones.
Mass-Spectra of Annelated 4H-3,1-Oxazin-4-ones
Authors: Dyall LK
Published: September 2010

Electron-impact fragmentation of 2-R-4H-3,1-benzoxazin-4-ones involves primary losses of CO2 and R; there is also loss of ketene when R is methyl. The ion RCO+ is a major daughter. Successive losses of CO2and RCN yield an ion m/z 76 formulated as dehydrobenzene radical cation. In the case of 2-methyl-4H-3,1-naphth[2,3-d]oxazin-4-one, the 2,3-dehydronaphthalene ion is produced efficiently, and linked scans (B/E) were used to demonstrate that it loses C4H2 ( diacetylene ) in a retro Diels-Alder reaction.
Terpenoid Chemistry. XXIX. (-)-Anymol From Myoporum crassifolium Forst, the C7 Epimer of (-)-α-Bisabolol From Camomile
Authors: Odonnell GW , Sutherland MD
Published: September 2010

The conflicting literature on the configurations of (-)-anymol, the major sesquiterpene alcohol of Myoporum crassifolium wood oil, and the α-bisabolols, is critically reviewed. (-)-Anymol [p-phenylazophenylurethane m.p. 105�, [α]D -7� (CHCl3/1% EtOH)] is shown to be the C7 epimer (farnesol numbering) of (-)-6S,7S-α-bisabolol (-)-2S,1′S-6-methyl-2-(4′methyl-cyclohex-3′-enyl)hept-5-en-2-ol] (p-phenylazophenylurethane, m.p. 129�, [α]D-0.8�) from Vanillosmopsis eryrhropappa Sch.-Bip. wood oil and hence also of the (-)-α-bisabolol from Matricaria charnomilla L. leaf oil. However the m.p. 104� and 17.7� ascribed by Babin, Fourneron and Julia to their p-phenylazophenylurethane of chamomile-derived (-)-α-bisabolol are anomalous despite the generation of the appropriate structure by X-ray diffraction.
The Stereoisomers of 5-Bromo-6,8-dimethoxy-1,2,3-trimethyl-1,2,3,4-tetrahydroisoquinoline. X-Ray Crystal-Structure of the trans Isomer
Authors: Rizzacasa MA , Sargent MV , Skelton BW , White AH
Published: September 2010

Henry reaction between 3,5-dimethoxybenzaldehyde (2) and nitroethane gave (E)-2-(3,5-dimethoxyphenyl)-1-methyl-1-nitroethene (3). Under mild conditions the erythro and threo nitro aldols intermediate in this reaction could be isolated as their acetates. The threo isomer was obtained in diastereoisomeric excess. The nitrostyrene (3) was converted in several steps into cis-(20) and trans-5-bromo-6,8-dimethoxy-1,2,3-trimethyl-1,2,3,4-tetrahydroisoquinoline (18). The single-crystal
X-ray structure of compound (18) is reported.
(-)-Bukittinggine, the Major Alkaloid of Sapium baccatum: Crystal Structure and Absolute Configuration of Bukittinggine Hydrobromide
Authors: Arbain D , Byrne LT , Cannon JR , Patrick VA , White AH
Published: September 2010

The structure and absolute configuration of (-)-bukittinggine (1), the major alkaloid isolated from the leaves of Sapium baccatum ( Roxb.) Ridley ( Euphorbiaceae ) have been determined from the crystal structure of its hydrobromide. Diffractometer data at 295 K were refined by least-squares techniques to a residual of 0.040 (3150 'observed' reflections). Crystals of bukittinggine hydrobromide are orthorhombic, P212121, a 14.947(4), b 14.580(4), c 8.801(2)Ǻ, Z4.
Imidazo[1,2-B]pyridazines. IX. Syntheses and Central Nervous System Activities of Some 3-Alkoxy-6-(o-alkoxy, o-methylthio- or o-fluoro-phenoxy)-2-arylimidazo[1,2-b]pyridazines
Authors: Barlin GB , Davies LP , Ireland SJ , Khoo CLY , Nguyen TMT
Published: September 2010

Syntheses are reported for a series of 6-(o-methoxy -, o-ethoxy -, o-methylthio - and o-fluoro-phenoxy )-3-( methoxy and ethoxy )-2- phenyl(substituted phenyl and pyridin-3″-yl) imidazo [1,2-b] pyridazines . IC50 values are reported for the displacement of 3H-diazepam from rat brain membrane by each of these compounds. The most active compounds were found to be 3-ethoxy-2-(p- fluorophenyl )-6-(o- methoxyphenoxy )-, 3-methoxy-6-(o- methoxyphenoxy )-2-(m-nitrophenyl )- and 3-methoxy-6-(o- methoxyphenoxy )-2-(3″,4″-methylenedioxy ) imidazo [1,2-b] pyridazines with IC5O values of 15, 18 and 19 nM respectively.