bluuebunny/crossref_metadata_2025 huggingface dataset:
3-Hydroxyumbilicaric Acid and 3-Methoxyumbilicaric Acid, New Tridepsides From the Lichen Parmelinopsis bonariensis
Authors: Elix JA , Jin Y , Adler MT
Published: September 2010

The new tridepsides 3-hydroxyumbilicaric acid (4) and 3-methoxyumbilicaric acid (5) have been detected in the lichen Parmelinopsis bonariensis and the structures established by unambiguous synthesis.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LI. Synthesis and Structural Characterization of Mononuclear Chloro-, Bromo- and Iodo-pyridinebis(triphenylphosphine)copper(I) Complexes
Authors: Engelhardt LM , Healy PC , Kildea JD , White AH
Published: September 2010

Complexes [ XCu ( py )(PPh3)2], X = Cl, Br, I, py = pyridine, have been synthesized and characterized by single-crystal X-ray structure determination. Chloride and iodide derivatives have similar cells [ isomorphous (?) but not isostructural ], triclinic, pi, a = 19.5 A, b = 10.5, c = 9.6 � , α ≈ 66, β ≈ 86, γ ≈ 83�, Z = 2; the bromide is monoclinic, Cc, a 13.568(9), b 15.760(12), c 16.545(8) � , β 95.65(5)�, Z = 4. Cl, Br, I structures were refined to residuals of 0.042, 0.055, 0.039 for 4288, 2241, 4808 'observed' reflections. In all cases, the copper atom is four-coordinate; for such an array, Cu-X lengths are unusually short [2.318(2), 2.459(2), 2.636(1) � (Cl, Br, I) and Cu-N unusually long (2.14(1) � ], while (Cu-P) increase from 2.264 to 2.288 � across the series. The dominant aspect of the complexes is thus that of XCu (PPh3)2 solvated by pyridine.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LIV. Synthesis and Structural Characterization of Binuclear μ,μ′-Dichloro-, Dibromo- and Diiodo-bis[(pyridine)(triphenylphosphine)silver(I)] Pyridine Solvate Complexes
Authors: Gotsis S , Engelhardt LM , Healy PC , Kildea JD , White AH
Published: September 2010

Mixed base pyridine (py)/triphenylphosphine adducts of the silver(I) halides, AgX (X = Cl, Br, I), have been synthesized for 1 : 1 : 1 stoichiometry. The three complexes are isomorphous and isostructural, being monoclinic, P21/c, a ≈ 11.2, b ≈ 16.8, c ≈ 16.5 � , β ≈ 122 � ; the complexes are centrosymmetric �, �?- dihalo -bridged dimers , [(PPh3)( py )AgX2Ag( py )(PPh3)1 (Z = 2 dimers ). Although the stoichiometry of the complex itself is as above, an additional unit of pyridine per silver atom is found as solvent in the lattice, implying the unlikelihood of the existence of an independent 1 : 2 : 1 AgX : py : PPh3 molecular series. In addition, the iodide has been isolated as a different C2/m (?) disordered polymorph.
Coordination Chemistry of the Calixarenes. III. A 2nd Phase of [Eu2(LH2)(Me2NCHO)5].Me2NCHO Solvate (LH8= p-t-Butyl-Calix[8]arene)
Authors: Harrowfield JM , Ogden MI , White AH , Wilner FR
Published: September 2010

The single-crystal X-ray structure of [Eu2(LH2)(Me2NCHO)5] has been recently described as an approximately tetrakisdimethylformamide solvate (L=C88H104O88-, the octaanion of p-t- butyl-calix [8] arene; Me2NCHO = N,N- dimethylformamide ). A second phase, a sesquidimethyl-formamide solvate ('β') has been isolated and also subjected to structural characterization; crystals are triclinic, P1, a 14.85(1), b 26.70(2), c 35.16(2) � , α 102.72(4), β 92.07(4), γ 101.61(4), (Z = 4 formula units); R was 0.12 for 14618 'observed' reflections. The two aggregates of the 8-phase, surprisingly in view of the expected flexibility of the large macrocycle, closely resemble that of the α-phase.
A Synthesis of the Lichen Diphenyl Ether Epiphorellic Acid 1
Authors: Elix JA , Jenie UA
Published: September 2010

The lichen diphenyl ether epiphorellic acid 1 [6-hydroxy-3-(5′-hydroxy-2′-methoxycarbonyl- 3′-pentylphenoxy)-4-methoxy-2-pentylbenzoic acid] (5) has been prepared by unambiguous synthesis. The synthesis employed a biomimetic -type approach which envolved a Smiles rearrangement of a precursor meta- depside in the key step.
Coordination of the Hexacyanoferrate(III) Anion to a Polyammonium Macrocycle. Crysta -Structure of [H4L]1.5[Fe(CN)6]2 (L=6,13-Dimethyl-1,4,8,11-tetraaza-cyclotetradecane-6,13-diamine)
Authors: Bernhardt PV , Lawrance GA , Skelton BW , White AH
Published: September 2010

Crystals of [H4L]1.5[Fe(CN)6]2.3H2O.¾HCN form readily from an aqueous solution of L=6HCI (L = 6,13-dimethyl-1,4,8,11- tetraazacyclotetradecane-6,13-diamine) and Na3 [Fe(CN)6]. The compound is monoclinic, space group P21/c, a 7.982(6), b 20.785(3), c 26.81(1) � , β 101.37(5), Z = 4. Protonation is complete at the terminal primary nitrogens, but in the ring one trans pair is protonated and the other not, with short trans H…H distances. Hydrogen-bonding interactions are a feature of the structure, but are concentrated more strongly at the terminal NH3+ groups. Interactions of [Fe(CN)6]3- nitrogens with both terminal amine protons and macrocycle ring amine protons are observed, and this structure represents a further example of a 'super complex' involving a complex anion and a protonated polyaza macrocycle.
The pH Dependence of the Ruthenium-Catalyzed Ferricyanide Oxidation of Cyclohexanol
Authors: Kaziro RW , Beattie JK
Published: September 2010

The oxidation of cyclohexanol to cyclohexanone by ferricyanide in alkaline aqueous solutions is catalysed by the addition of chlororuthenium compounds. In solutions of pH less than 11 the progress of the reaction is limited by the decomposition of the catalyst in its reduced state. The catalyst lifetime can be lengthened by an increase in the concentration of the ferricyanide oxidant. In solutions of pH 11.3-11.9 either of the oxidation or the reduction steps of the catalytic cycle can be made rate determining, by adjustment of the relative concentrations of cyclohexanol and ferricyanide . The decrease in rate with increase in pH is due to the pH dependence of the reaction of the oxidized catalyst. The rate constant decreases from 26 to 15 dm3 mol-1 s-l between pH 11.3 and 11.9. The rate constant for the ferricyanide oxidation of the reduced catalyst is pH-independent at (6 � 2)×102 dm3 mol-1 s-1 at 298 K, over the same pH range.
Acid-Catalyzed Hydration of Prop-2-en-1-ol and 2-Methylprop-2-en-1-ol: Correlation of Reactivity
Authors: Herlihy KP
Published: September 2010

The kinetics of the acid-catalysed reaction of prop-2-en-1-ol and 2-methylprop-2-en-1-ol have been measured. The relative reactivity, solvent isotope ( kH+/kD +) and change in acidity effects, and activation parameters, have been determined and found to be similar to those of other alkenes. While this correlation of results for the hydration of both these alkenols can be interpreted in terms of the conventional Ad-E2 mechanism, computed values for the lifetime of possible carbocation intermediates suggest that an alternative mechanism for the reaction of prop-2-en-1-ol, in which nucleophilic attack by the solvent is concerted with protonation, is feasible.
Stereoselective Preparation of Bicyclo[3.3.0]octanones From the Products of Aprotic Conjugate Addition of Lithiated Allylic Sulfoxides to Cyclopent-2-enone and Enolate Trapping With Methyl Cyanoformate
Authors: Haynes RK , Katsifis AG
Published: September 2010

The lithium enolates arising by aprotic conjugate addition of lithiated but-2-enyl sulfoxides and a phosphine oxide to cyclopent-2-enone react efficiently with methyl cyanoformate to give the corresponding methyl 5-oxocyclopentanecarboxylates in good yields. The sulfoxides are smoothly deoxygenated with tributylphosphine diiodide in ether at 0�, and the resulting sulfides undergo intramolecular cyclization in the presence of tin(IV)chloride to give methyl oxobicyclo [3.3.0] octanecarboxylates , again in good to excellent yields. The cyclizations are highly stereoselective in that the syn- and anti-stereochemistries of the enolate trapped products obtained from (E)-and (Z)- sulfoxides are quantitatively reflected in the products obtained from the cyclization reactions.
Stereoselective, Base-Induced Formation of Bicyclo[2.2.1]heptanones and Bicyclo[3.2.1]octanols From the Products of Conjugate Addition of Lithiated Allylic Sulfoxides and Phosphine Oxides to Cyclopent-2-enone
Authors: Haynes RK , Katsifis AG
Published: September 2010

Treatment of the neutral cyclopentanone adducts derived from the conjugate addition of each of lithiated 3-methylbut-2-enyl phenyl sulfoxide, (E)- and (Z)-but-2-enyldiphenylphosphine oxide to cyclopentenone with potassium t-butoxide results in intramolecular conjugate addition of the enolate arising from deprotonation at C5 of the cyclopentanone with the vinyl sulfoxide or phosphine oxide in the side chain togenerate bicyclo[2.2.l]heptanones in good yields. The use of an excess of lithium diisopropylamide at low temperature on the other hand results in kinetic deprotonation of the vinylic sulfoxide or phosphine oxide, and intramolecular nucleophilic addition of the resulting vinylic anions to the carbonyl groups in the respective adducts to generate bicyclo[3.2.l]octanols in acceptable yields. Application of the latter reaction to the lactone adduct of lithiated 3-methylbut-2-enyl phenyl sulfoxide and crotonolactone results in ring opening of the lactone to give a 2-(phenylsulfinyl)cyclohex-2-enone.
Coupling to sp-Hybridized Carbon: 13C-13C Coupling Constants in Some Polycycloalkanecarbonitriles
Authors: Della EW , Gangodawila H
Published: September 2010

Comparison of the effect of sp-hybridized carbon on the magnitude of directly bonded and vicinal coupling constants in the labelled nitriles (1)-(7) with that of sp2 and sp3 carbon reveals some interesting, though not major, differences. As noted previously, three-bond coupling involving the labelled carbon and the bridgehead carbon in the bicyclo[n.1.1] alkanes has an important through-space component.
Enolic Ortho Esters. III. Preparation of a Keto Acetal by Hydride Reduction of an Enolic Ortho Ester
Authors: Collins DJ , Downes LM , Kyriakou M
Published: September 2010

Lithium aluminium hydride reduction of the enolic ortho ester 4′,4′-dimethyl-3,4,5,8-tetra-hydrospiro [2H-l-benzopyran-2,21-[1,3]dioxolan] (8) in the absence of solvent gave 6-[21-(4″,4″- dimethyl-1″,3″-dioxolan-2″-yl)ethyl]cyclohex-3-en-1-one (11) which was isomerized to the α'β-unsaturated keto acetal (10). Similarly, hydride reduction of the phenolic ortho ester 4′-methyl-3,4-dihydrospiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (12a)
and the 4′,4′-dimethyl analogue (12b), afforded the corresponding phenolic acetals (14a) and (14b) respectively, in high yields.′
Isolation and X-Ray Crystal Structure of (E)-4-(r-1',t-2',c-4'-Trihydroxy-2',6',6'-trimethyl-cyclohexyl)but-3-en- 2-one, a Constituent of New Zealand Thyme Honey
Authors: Tan ST , Wilkins AL , Holland PT
Published: September 2010

A trihydroxy ketone isolated from the extractives of New Zealand thyme honey has been shown by X-ray crystallographic analysis to be (E)-4-(r-1′,t-2′,c-4′-trihydroxy-2′,6′,6′- trimethylcyclohexyl)but-3-en-2-one. Since this compound appears to occur only in thyme honeys, its presence is considered to afford a chemical procedure for the verification of floral source.
Copper(II) and Cobalt(III) Complexes of a Mixed Secondary and Tertiary Nitrogen Donor Tetraaza Macrocycle. Crystal Structure of Aqua(7-methyl-7-nitro-1,5,9,13-tetraaza-bicyclo[11.2.2]heptadecane)copper(II) Perchlorate Hydrate
Authors: Engelhardt LM , Lawrance GA , Manning TM , White AH
Published: September 2010

Reaction of (bis(3-aminopropyl) piperazine )copper(11) ion with nitroethane and formaldehyde in basic methanol results in the ready formation of (7-methyl-7-nitro-1,5,9,13- tetraazabicyclo [11.2.2] heptadecane )copper(11) ion in high yield. The perchlorate salt of the macrocyclic complex crystallizes in the orthorhombic space group Pbca, a 19.144(8), b 17.499(5), c 14.635(5) �, Z=8, with the copper ion in a square-pyramidal environment of four nitrogen donors and a water molecule. The Cu-secondary N and Cu-tertiary N distances are 2.044(8), 2.056(8) and 2.053(8), 2.072(8) � respectively, with the Cu-O distance 2.259(8)�. Reduction of the complex with Zn/ HCl yields the 7-methyl-1,5,9,13-tetraazabicyclo [l1.2.2]heptadecane-7-amine analogue, characterized as copper(II) and cobalt(III) complexes. The cobalt(III) complex contains the latter macrocycle as a quinquedentate ligand with the pendant primary amine coordinated trans to a chloride ion, identified as the only isomer by chromatography, and characterized by electronic and n.m.r. spectroscopy. Consequences of 'reinforcement' of the macrocycle by the extra ethane bridge are discussed.
Synthesis of 1-(α-Acyloxy-2-hydroxybenzyl)Azoles and Related Compounds by an Acyl Transfer Reaction
Authors: Liepa AJ , Liepa AJ , Morton TC , Morton TC
Published: September 2010

Novel azole adducts were produced by reaction of azoles and 2-acyloxyaryl aldehydes. The mechanism of the reaction involves attack by the azole at the carbonyl group and transfer of the acyl group to form an azole-substituted benzylic ester. 2-Acyloxyaryl ketones did not undergo an analogous reaction. An aminal was formed rather than an azole-substituted benzylic carbonate when a 2-aryl aldehyde carbonate was used as substrate.
Alkaloids of Daphnandra dielsii. I. Tertiary Bases. Isolation and Structural Determination of Dielsine
Authors: Critchett CD , Dharmaratne HRW , Sotheeswaran S , Galal AM , Schiff PL , Bick IRC
Published: September 2010

The isolation and structural determination of the new alkaloid dielsine (3), which belongs to the small group of repanduline-type bases, are described.
Base Catalyzed Rearrangement of Isoxazolinyl Heterocycles: Synthesis of Annelated Pyrimidines
Authors: Donati C , Janowski WK , Prager RH , Taylor MR , Vilkins LM
Published: September 2010

The rearrangement of a number of ethyl 2-(heterocyclic)-5-oxo-2,5-dihydroisoxazole-4-carb-oxylates by mild base is described, leading to new syntheses of the pyrimido [2,1-a] isoquinoline, pyrimido [1,2-a]quinoline, pyrimido [2,1-b] benzothiazole , pyrirnido [1,2-a] pyrimidine, pyrimido [1,2-b]pyridazine and pyrimido [1,2-c] quinazoline ring systems. A mechanism is suggested, and X-ray crystallographic evidence presented for the structure of one of the products, ethyl 2-hydroxy-4-oxo-4H-pyrimido[2,1-a]isoquinoline-3-carboxylate.
Reactions of N-Acyloxy-2-nitrobenzenamines. I. Thermolysis in Benzene or Bromobenzene
Authors: Bryant IR , Dyall LK
Published: September 2010

N-Acyloxy-2-nitro- and N-acyloxy-2,4-dinitro-benzenamines have been pyrolysed at 140� in benzene or bromobenzene solution. Homolysis (to form RCO2 and ArNH ) is ruled out since virtually all the carboxylate is isolated as carboxylic acid. This acid might arise via a concerted elimination process (the other product being a benzofurazan 1-oxide), or via heterolysis to ArNH+, RCO2- with subsequent transfer of proton, and cyclization of the singlet 2-nitrophenylnitrene. These simple reactions compete with bimolecuiar reactions of products with substrate, in which the corresponding amine, azoxy compound and acid anhydride are generated. Attempts to synthesize N-tosyloxy derivatives of nitrobenzenamines gave only thermal decomposition products. N-Trifluoroacetoxy-2,4-dinitrobenzenamine was isolated as a crude product which detonated violently.
The Chemistry of Pyrimidinethiols. III. The Synthesis of Some Substituted Pyrimidinthiols and Some Thiazolo[5,4-D]pyrimidines
Authors: Harnden MR , Hurst DT
Published: September 2010

The preparation of a number of pyrimidinethiols and (substituted) thiopyrimidines has been carried out. The reaction of 5-acetylamino-2-aminopyrimidine-4,6-diol with phosphorus penta -sulfide in pyridine gave 5-amino-2-methylthiazolo[5,4-d]pyrimidine-7-thiol which was used to prepare several additional novel pyrimidine derivatives. Hydrolysis of the 4-carboxymethylthio derivative by using 5M hydrochloric acid gave 2,5-diamino-6-mercaptopyrimidin-4-ol hy -drochloride whilst hydrolysis of 2-methyl-7-methylthiothiazolo[5,4-d]pyrimidin-5-amine gave the corresponding 4-hydroxy derivative. Several 4-arenecarbonylmethylthio derivatives were recovered unchanged from such hydrolysis reactions.
The Cycloaddition Reactions of Some 7-Alkylidenecycloocta-1,3,5-trienes
Authors: Ferber PH , Gream GE , Kirkbride PK , Tiekink ERT
Published: September 2010

A number of 7-alkylidenecycloocta-1,3,5-trienes, all unstable, yield novel π8+π2 cycloadducts with a range of π2-addends. The reactions of 7-methylenecycloocta-1,3,5-triene with ethene-tetracarbonitrile, 4- phenyl-1,2,4-triazoline-3,5-dione, diethyl azodicarboxylate and chlorosulfonyl isocyanate are described. The tetraene did not react with maleic anhydride or dimethyl acetylenedicarboxylate. As well, the reactions of 1,3,5-trimethyl-7-methylenecycloocta-1,3,5-triene, 2,9a- dihydro-1H-cyclopentacyclooctene and 1,2,3,10a- tetrahydrobenzocyclooctene with ethenetetracarbonitrile and of 7- isopropylidenecycloocta-1,3,5-triene with 4-phenyl-1,2,4-triazoline- 3,5-dione are discussed. The intermediacy of homotropylium zwitterions in the reactions is postulated.
Syntheses of Confertifolin, Winterin and Isodrimenin Congeners From Podocarpic Acid
Authors: Cambie RC , Grimsdale AC , Rutledge PS , Woodgate PD
Published: September 2010

Podocarpic acid (11) has been converted into the congener (5) of confertifolin (4) through the o-quinone (29) formed by oxidations of the catechol monoether (15) and the 13-amine (16) with Fremy's salt. Oxidation of the methyl ether (12) afforded the p- quinone (44) which was converted into the congener (6) of winterin (7). Podocarpic acid has also been converted into the congener (8) of isodrimenin (9) through the catechol derivative (37).
The Reactions of Some Substituted 2-Hydroxybenzonitriles With Nitrogen Dioxide: X-Ray Structures of 2-Cyano-t-6-hydroxy-3,4,5,6-tetramethyl-r-4,t-5-dinitrocyclohex- 2-enone, 2-Cyano-3,4,5,6-tetramethyl-r-4,t-5,t-6-trinitrocyclohex-2-enone and 2-Cyano-c-6-h-4,6-dimethyl-r-4,c-5-dinitrocyclohex-2-enone
Authors: Gordon JLM , Hartshorn MP , Robinson WT , Sies CW , Wells BA , Wikaira JL , Wright GJ
Published: September 2010

Reaction of 2-hydroxy-3,4,5,6-tetramethylbenzonitrile (1c) with nitrogen dioxide gives predominantly the 4,5,6-trinitrocyclohex-2-enones (9) and (10a,b), with lower yields of the 4-nitro dienone (5a) and the 6-hydroxy-4,5-dinitrocyclohex-2-enone (6). Reaction of 2-hydroxy-3,5-dimethylbenzonitrile (2b) with nitrogen dioxide gave the C4-epimeric 6-hydroxy-4,5-dinitrocyclohex-2-enones (11) and (12). Reaction of 2-hydroxy-3,5,6-trimethyl- benzene-1,4-dicarbonitrile (4) with nitrogen dioxide gave the 4-hydroxy dienone (15) and the 6-hydroxy dienone (16). X-Ray structure determinations are reported for compounds (6), (9) and (11).
N.M.R.-Study of Bond Orders in o- and p-Quinone
Authors: Gready JE , Hata K , Sternhell S , Tansey CW
Published: September 2010

The 4J(Me-CC-H) coupling constant, previously established as a probe of bond order,1-3 was used to examine bond orders in a number of quinones. It was found that the presence of a quinone moiety does not cause bond localization in aromatic rings adjacent to the quinone ring.
Preparation of β-Keto Ester Acetals by Reaction of Ortho Esters With Ketene Silyl Acetals in the Presence of Titanium Tetrachloride
Authors: Collins DJ , Choo GLP , Obrist H
Published: September 2010

Reaction of 2-ethoxy-2-methyl-1,3-dioxolan (1c) with 1-methoxy-1-trimethylsilyloxyethene (4a) in dichloromethane in the presence of titanium tetrachloride gave 62% of methyl 2-(2′-methyl-1′,3′-dioxolan-2′-yl)acetate (5a). Similarly, reaction of (1c) with l-methoxy-1-trimethylsilyloxyprop-1-ene (4b) afforded 73% of methyl 2-(2′-methyl-1′,3′-dioxolan-2′-yl) propanoate (5b).
New Fernene Triterpenes From the Lichen Pseudocyphellaria aurata
Authors: Wilkins AL , Elix JA
Published: September 2010

Four new triterpenes identified as 3β-acetoxyfern-9(11)-en-12-one (2b), 3β-acetoxyfern-9(11)-en-12β-ol (2g), fern-9(11)-ene-3β,12β-diol (2f) and 3β-acetoxyfern-9(11)-en-19β-ol (2h) have been isolated from the extracts of the lichen Pseudocyphellaria aurata. Lupeol acetate (1) and 3β-hydroxyfern-9(11)-en-12-one (2a) were also present in the extracts.
The Synthesis and Structure of 3,4-Di-t-butylbenzoic Acid
Authors: Hambley TW , Hambley TW , Sternhell S , Sternhell S , Tansey CW , Tansey CW
Published: September 2010

3,4-Di-t-butylbenzoic acid (1) was synthesized by a seven-step sequence from 4-t-butylbenzoic acid, and its structure was determined by X-ray diffraction and refined to a residual of
0.065 for 1403 independent observed reflections. The crystals are triclinic, Pī , a 6.080(1), b 8.777(1), c 13.912(3)Ǻ, α 80.76(2), β 80.84(2), γ 75.62(2)°. It is the only example of a simple ortho-di-t-butylbenzene whose structure has been determined. The benzene ring experiences some out-of-plane distortion but, in general, strain is relieved by in-plane bond stretching and angular distortions.
The Chemistry of Pyrrolic Compounds. LXV. Intramolecular Cyclization of Porphyrins With Acetic Acid Side Chains: Hydroxy Derivatives of Deoxophylloerythroaetioporphyrin (DPEP)
Authors: Clezy PS , Mirza AH , Prashar JK
Published: September 2010

The intramolecular cyclization of porphyrins substituted with an acetic acid side chain has been studied under a range of conditions but the yield of product bearing a fused five- membered ketonic ring system was disappointingly low. Deoxophylloerythroaetioporphyrin (DPEP) derivatives with hydroxy groups at either C 13′ or C 15′ have been prepared by reduction of the corresponding ketones. 1H n.m.r . data for the latter alcohol matches well that reported for a porphyrin obtained from Marl Slate and which is probably derived from DPEP, by oxidation, during the extraction process.
Quantum Mechanical Tunneling in Homodienyl Sigmatropic [1,5]-Hydrogen Shifts of (Hydroxymethyl)styrylcyclopropanes
Authors: Pegg GG , Meehan GV
Published: September 2010

The strong temperature dependence of the deuterium kinetic isotope effect observed for homodienyl [1,5]-hydrogen migration of [hydroxy (D)methyl] styrylcyclopropanes (1c,d) in hexane solvent is suggestive of a significant tunnelling contribution to the mechanism. While the hydroxy substituent at the migration origin appears to influence the thermolytic behaviour of these molecules, attempts to promote oxy anionic homodienyl rearrangement in the isotopically natural compounds (1a,b) at low temperature were unsuccessful.
Alkaloids of Daphnandra dielsii. II. Daphnine. Isolation and Characterization
Authors: Howard AS , Harleymason J , Bick IRC
Published: September 2010

The isolation and characterization of the unique orange-yellow bisbenzylisoquinoline alkaloid daphnine (1) are described.
A Further γ-Pyrone Derivative From the Marine Red Alga Phacelocarpus labillardieri
Authors: Blackman AJ , Bremner JB , Paano AMC , Skerratt JH , Swann ML
Published: September 2010

A new brominated macrocyclic γ-pyrone (4) and β- farnesene have been isolated from a Tasmanian collection of Phacelocarpus labillardieri.
N.M.R. Studies of Bond Order in Sterically Distorted Phenanthrenes
Authors: Sternhell S , Tansey CW
Published: September 2010

The 4J(H-C-C-Me) coupling constant, previously established1-3 as a probe of bond order, was used to examine the bond orders in 2,4,5,7-tetramethylphenanthrene. There was no evidence indicating disturbance of π-electron distribution in the C1/C2 and C2/C3 bonds, despite large deviations from planarity in the carbon skeleton of the molecule.
A Stereocontrolled Synthesis of proto-Quercitol
Authors: Cambie RC , Renner ND , Rutledge PS , Woodgate PD
Published: September 2010

Conduritol A tetramethyl ether (2) has been converted by hydroboration-oxidation into proto-quercitol tetramethyl ether (5) which on demethylation afforded a mixture (2 : 1) of proto-quercitol (4) and vibo-quercitol (11). proto-Quercitol was also obtained (15%) from conduritol A tetrabenzoate (3) by a similar sequence.
Electrochemical Characteristics of the Copper(II)-Copper(I) Redox Couple in Dimethyl Sulfoxide Solutions
Authors: Benari MD , Hefter GT
Published: September 2010

A study of the electrochemical characteristics of the copper(II)/copper(I) redox couple has been made in chloride and bromide media in dimethyl sulfoxide (Me2SO) and their aqueous analogues. The formal potentials of the CuII/CuI couple in the Me2SO media are approximately 0.15 V less positive than in their aqueous counterparts probably due to a combination of solvation and complexation effects. Diffusion coefficients for both CuI and CuII are 5-10 times lower in Me2SO than in H2O as a result of the higher viscosity of Me2SO solutions. Heterogeneous electron-transfer rate constants for the CuII/CuI system on platinum are also an order of magnitude smaller than in aqueous solution. In general the electrochemical characteristics of the CuII/CuI system parallel those reported elsewhere for the FeIII/FeII couple. However, a detailed investigation of the CuII/CuI system by cyclic voltammetry indicates that the overall electrode process is complex, probably involving a quasi-reversible electron-transfer step coupled to a rate-determining loss of Cl - from CuII.
On the Charge Density Distribution in Cobalt(III) Ammine Hexacyanochromate(III) Complexes
Authors: Reynolds PA , Figgis BN
Published: September 2010

A charge density refinement using effective anharmonic isotropic thermal parameters was performed on the X-ray diffraction data for pentaammineaquacobalt(III) hexacyanochromate(III) and for hexaamminecobalt(III) hexacyanochromate(III), constraining the unit cells of the crystals to be electically neutral. Our previous refinements, which did not admit of anharmonicity, could not simultaneously give a good fit and provide electroneutrality of the unit cell. The effective anharmonic parameters correct a systematic error observed in these, and, less extremely, in other transition-metal complex crystals. Values of the derived charge density parameters change mostly at less than the 2σ level of significance in the new refinements except for overall ionic charges. It seems the limitations in our earlier refinements did not lead to serious errors in the chemical conclusions reached, apart from the ionic charges. In the [Co(NH3)5(OH2)][Cr(CN)6] case we observe five significant charge flows; from CN to Cr, σ bonding 0.5(3), and π back-bonding 0.6(2) e; from NH3 and H2O to Co, σ bonding 0.7(3), and π back-bonding 0.5(2) e; and a transfer of 1.5(4) from Cr(CN)6 to Co(NH3)5(H2O) through 17 CN…H hydrogen bonds, with N…H(3) noticeably more important. Bond overlap densities are also significant. The relative sizes of these charge flows are similar for the isomorphous hexaamminecobalt(III) hexacyanochromate(III) salt.
Electrochemical Synthesis of 2',3'-Dideoxy-2',3'-didehydrocytidine and 2',3'-Dideoxycytidine
Authors: Johansen O , Holan G , Marcuccio SM , Mau AWH
Published: September 2010

An improved electrochemical procedure for the synthesis of N4,O5′-diacetyl-′,3′-dideoxy-2′,3′-didehydrocytidine (8) has been established. The compound (8) was used as an intermediate in the syntheses of 2′,3′-dideoxy-2′,3′-didehydrocytidine (9) and 2′,3′-dideoxycytidine (2).
Coordination of 6-Methyl-2,2'-bipyridine. Structure of Bivalent Copper and Palladium Complexes
Authors: Onggo D , Craig DC , Rae AD , Goodwin HA
Published: September 2010

Bis ( ligand ) complexes of 6-methyl-2,2′-bipyridine (L) with copper(II) and palladium(II) have been prepared, and their structures have been determined by single-crystal X-ray diffractometry . In the formation of the complex fromcopper(II) tetrafluoroborate and L, partial hydrolysis of a coordinated fluoroborate ion to the hydroxytrifluoroborate ion occurs. The stereochemistry about copper in [CuL2OHBF3][BF4] is essentially trigonal bipyramidal with an axial compression. The nitrogens of the methyl-substituted pyridine rings coordinate in the axial sites. In [PdL2Cl][BF4] the coordination environment about palladium is square planar and one of the 6-methylbipyridine molecules functions as a unidentate group, the nitrogen of the methyl-substituted pyridine ring being uncoordinated. The average metal-nitrogen distance is 2.032 Ǻ in the copper complex and 2.042 Ǻ in the palladium complex. [CuL2OHBF3][BF4] is monoclinic, space group P21/c, Z = 4, a 9.005(2), b 17.868(2), c 15.298(3) Ǻ, β 104.13(1)°. [PdL2Cl][BF4] is monoclinic, space group P21/c, Z = 4, a 9.606(5), b 14.748(2), c
16.311(8)Ǻ, β 96.13(2)°.
Synthesis and Further Ring-Forming Reactions of a New 3-Amino-isoquinoline-4-carbaldehyde
Authors: Argiropoulos G , Deady LW , Dorkos M
Published: September 2010

The synthesis of 3-amino-6-(p- methylphenoxy )isoquinoline-4-carbaldehyde in two steps from the corresponding ethyl ester is reported. Further ring annulations by Friedlander synthesis are described to give, for example, new tetra- and penta -cyclic systems ( benzo [f] pyrimido [4,5-b][1,8] naphthyridine and benz [f] indolo [3,2-b][1,8] naphthyridine ).
Conversion of 2-Oxomanoyl Oxide Into an Analog of Pisiferic Acid
Authors: Cambie RC , Moratti SC , Rutledge PS , Woodgate PD
Published: September 2010

An analogue (3) of pisiferic acid (1), a known antibiotic, has been prepared from 2-oxomanoyl oxide (9) through a lead tetraacetate induced long-range oxidation.
Vinylindenes and Some Heteroanalogs in the Diels-Alder Reaction. X. Dibenzofurans From 3-Vinylbenzofurans
Authors: Pearson JR , Porter QN
Published: September 2010

3-Vinylbenzofuran, 3-isopropenylbenzofuran and 2-methyl-3-vinylbenzofuran give normal [4π+2π] adducts with ethenetetracarbonitrile, accompanied, in the case of the last named diene, by the isomeric cyclobutane. Normal adducts also result from these dienes and 4-phenyl-1,2,4-triazoline-3,5-dione, and from 3-vinylbenzofuran and both maleic anhydride and N- phenylmaleimide. 3-Vinylbenzofuran gives the
rearranged adduct dimethyl 1,2-dihydrodibenzofuran-3,4-dicarboxylate with dimethyl acetylenedicarboxylate.
Anodic-Oxidation Products of 2',5'-Dimethoxyacetanilide Derivatives, and Their Application to the Synthesis of Aminoanthraquinones
Authors: Russell RA , Longmore RW , Warrener RN
Published: September 2010

Anodic oxidation of simple 2′,5′-dimethoxyacetanilides proceeds under mildly basic conditions to afford either monomeric or dimeric quinone bisacetals, depending on the structure of the substrate. Similarly, the oxidation of linked derivatives of 2′,5′-dimethoxyacetanilides is shown to exhibit a comparable sensitivity, with non-alkylated amides being efficiently converted into bis(quinone bisacetals). The regiospecificity of acetal hydrolysis for both simple and linked quinone bisacetals is shown to be dependent upon the nature of the N-acyl group. The annelation of these hydrolysis products with the anion of 3-cyanophthalide to yield (acylamino)anthraquinones is also reported.
Pigments of Fungi. XXIII. Approaches Towards (±)-Austrocortirubin From 3-Methyl-1-trimethylsilyloxybuta-1,3-diene
Authors: Burns CJ , Gill M , Binothman AH , Skelton BW , White AH
Published: September 2010

The products (5) and (21) of cycloaddition between 3-methyl-1-trimethylsilyloxybuta-1,3-diene (3) and naphthazarin (4), and between (3) and the naphthopurpurin acetal (2), respectively, are converted into the tetrahydroanthraquinones (16)-(18), (26) and (27) via a series of intermediate epoxy alcohols. Stereochemical assignments are corroborated by a single-crystal X-ray structure analysis of the bromohydrin (16). The tetrahydroanthraquinones (27) and (18), advanced intermediates in a proposed synthesis of the fungus pigment austrocortirubin (1) and its 6-demethoxy analogue (20), respectively, are resistant to efficient dehalogenation.
Molecular-Structures and Conformations of 9,9'-Anthroin ('α' and 'β' Forms), 9,9'-Anthroin Acetate, and Some Related Benzoin Derivatives
Authors: Becker HD , Kildea JD , Patrick VA , Skelton BW , White AH
Published: September 2010

The molecular conformations of 9,9′-anthroin (two forms, 'α' and 'β') and its acetate, as well as those of the acetates of benzoin and p- anisoin , have been studied by X-ray diffraction methods and found to display similar characteristics in respect of the COCO moiety. The conformation of 1,2-diaryl acyloins is characterized by a small torsion angle (10-24°) about the central four-atom fragment O=C-C-O, and the intramolecular distance between the two oxygen atoms does not exceed 2.8 Ǻ. The torsion angle about the three-bond segment Ar-C-C-Ar is in all cases smaller than 90°. In benzoin and its derivatives, the arylcarbonyl group deviates from planarity by 4-12°. In the cases of β 9,9′-anthroin and its acetate, the carbonyl group is twisted out of the plane of the anthracene moiety by 75°, and the two anthracene π-systems are in an overlapping arrangement; for α-anthroin, despite the presence of disorder in the COCOH moiety, a similar disposition can be inferred, indicative overall that, for such species, hydrogen bonding is not necessarily dominant in determining conformation.
Synthesis of 7-Substituted Indoles as Potential Ligand Precursors
Authors: Black DS , Deacon GB , Edwards GL
Published: September 2010

Some 7-(pyridin-2′'-yl)- and 7-(pyrazol-1′-yl)-indole-2-carboxylic esters (14)-(16) and the related acids (17) and (18) have been synthesized through the Fischer indole cyclizations of the ethyl pyruvate hydrazones (9)-(12), which were in turn derived from the ortho -functionalized anilines (5)-(8) by diazotization and coupling with ethyl 2-methyl-3-oxobutanoate (the Japp-Klingemann reaction).
Sirodesmin Biosynthesis
Authors: Bulock JD , Clough LE
Published: September 2010

Using DL-[3,5-3H,U-14C]tyrosine it is shown that in the biosynthesis of sirodesmins all nine carbon atoms of tyrosine are incorporated into the rearranged structure. Using [13C21acetate it is confirmed that the biosynthesis proceeds by way of a type of Claisen rearrangement of an O-(3,3-dimethylallyl)tyrosine derivative, and the chirality of this rearrangement is established. The order and stereochemical implications of other steps in the biosynthesis are considered.
Synthetic and Structural Studies in the Lanthanide Toluene-4-sulfonate Hydrates
Authors: Faithfull DL , Harrowfield JM , Ogden MI , Skelton BW , Third K , White AH
Published: September 2010

Single-crystal X-ray structure determinations at c. 295 K are reported for representative members of the hydrated toluene-4-sulfonates of the lanthanide elements. The early members of the series, represented by lanthanum, cerium and neodymium, are monoclinic tridecahydrates , space group C2/c, a ≈ 32, b ≈ 7.2, c ≈ 35 �, β ≈ 115 �, Z = 8; the cation is a tricapped trigonal prismatic nonaaqualanthanide (III) species, with three toluene-4-sulfonate counter ions and four lattice water molecules per formula/asymmetric unit. The later members of the series, represented by samarium, lutetium and also yttrium, are, in agreement with contemporary work, monoclinic nonahydrates , space group P21/n, a ≈ 25, b ≈ 7.5, c ≈ 17.8 � , β ≈ 99�, Z = 4; the cation is a square prismatic hexaaquabis (toluene-4-sulfonato)lanthanide(III) species with a single toluene-4-sulfonate counter ion and three lattice water molecules. The solid state dehydration reactions of the tridecahydrates are complicated but there is at least one more endothermic step than is observed for the nonahydrates , with both series of compounds appearing to undergo water loss only below 300�C.
Preparation of Hybrid Bidentate Phosphine-Ligands by Reduction of Their Benzylphosphonium or Phenylphosphonium Salts - X-Ray Crystal-Structure of 2-Aminophenyltriphenylphosphonium Tetrachloronickelate(II)
Authors: Cooper MK , Downes JM , Duckworth PA , Tiekink ERT
Published: September 2010

The 2-substituted phenylphosphine bidentate hybrid ligands, 2-aminophenyl-, 2-methylamino- phenyl-, 2-hydroxphenyl- and (2-amino-3-methylpheny1)- diphenylphosphine , (1a-d), respectively, and 2-aminophenylmethylphenylphosphine, (le), were synthesized by reduction of their phenylphosphoniurn halides, (2a-e)X (X = Cl or Br), with sodium naphthalenide in tetrahydrofuran at -68�, or electrochemically at a mercury cathode. The phosphonium salts were prepared by reaction of triphenylphosphine with aryl halide and anhydrous nickel halide at 200�. X-Ray diffraction of (2a)2 [NiCl4] showed it to have monoclinic space group P21/n, a 10.657(4), b 20.966(3), c 20.422(6) � , β101.33(2)

and Z4.
The structure was refined by a full-matrix least-squares procedure to a final R 0.050 for 3534 reflections with I
Imidazo[1,2-b]pyridazines. X. Syntheses and Central Nervous System Activities of Some 3-(Acetamido, benzamido, substituted benzamido or dimethylamino)methyl-2-(phenyl or substituted phenyl)-6-(halogeno, alkylthio, alkoxy, phenylthio, phenoxy, benzylthio or benzyloxy)imidazo[1,2-b]pyridazines
Authors: Barlin GB , Davies LP , Ireland SJ , Ngu MML , Zhang JK
Published: September 2010

Syntheses of some 3-( acetamido, benzamido , substituted benzamido or dimethylamino)methyl-2-(phenyl or substituted phenyl)-6( halogeno, alkylthio, alkoxy, phenylthio, phenoxy , benzylthio or benzyloxy ) imidazo [1,2-b] pyridazines from the 3-unsubstituted analogues are described. The IC50 values (or percentage displacements) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compounds. .The 3-benzamidomethyl compounds were generally the most active; of these, 3-benzamidomethyl-2-(3',4'-methylenedioxyphenyl)-6-methylthioimido[1,2-b] pyridazine showed outstanding activity with IC50 2 nM .
Preparation of Bicyclic Herbicide Precursors by Intramolecular Stork-Danheiser Kinetic Alkylation Reactions of Methyl 1-(Haloalkyl)-3-methoxy-5-oxocyclohex-3-ene-1-carboxylate Derivatives
Authors: Liepa AJ , Liepa AJ , Wilkie JS , Wilkie JS , Winkler DA , Winkler DA , Winzenberg KN , Winzenberg KN
Published: September 2010

Reductive alkylation of methyl 3,5-dimethoxybenzoate with the dibromoalkane and the bromochloroalkane derivatives (4a-d) and (4e-g) afforded, after acid hydrolysis, the corresponding methyl 1-( haloalkyl )-3-methoxy-5-oxocyclohex-3-ene-1-carboxylate derivatives (6a-g). Reaction of (6a-c) with lithium diisopropylamide afforded methyl 3-methoxy-5-oxobicyclo[4.2.0]oct-3-ene- 1-carboxylate (2a), methyl 5-methoxy-7-oxo-1,2,3,4,7,7a-hexahydro-3aH-indene-3a-carboxylate (2b) and methyl 6-methoxy-8-oxo-1,3,4,5,8,8a-hexahydronaphtha1ene-4a(2 H)- carboxylate (2c), respectively. Compounds (2b) and (2c) were also obtained from the reaction of (6f) and (6g) with lithium diisopropylamide . Compounds (2a) and (2b) were each obtained as a single bridgehead isomer, the relative stereochemistry of ring fusion of which was assigned as cis on the basis of semiempirical molecular orbital calculations. Compound (2c) was obtained as a mixture of cis-and trans-fused bridgehead isomers. The ester (2b) was converted into the herbicide methyl 5,7-dioxo-6-[1-[(prop-2-enyloxy) imino ] butyl]octahydro-3aH-indene-3a-carboxylate (3a).
Heterobinuclear Oxo-Bridged Complexes. III. CrIIIOmoV Compounds—Synthesis and Magnetic Properties
Authors: Elliott RL , Kruger P , Murray KS , West BO
Published: September 2010

Redox reactions between CrIVO (P) (P is a porphyrin dianion ) and MoIVO( dtc )2 ( dtc is adithiocarbamate anion) result in the formation of oxo -bridged Cr111OMOV compounds. The variation of magnetic susceptibility with temperature to 25 K shows evidence for strong antiferromagnetic coupling for the pyrrolidyldithiocarbamate complex with J = -300 cm-1.
Structural Studies of Bicyclo[3.2.1]octane and Bicyclo[2.2.2]octane Diols
Authors: Dastlik KA , Ghisalberti EL , Skelton BW , White AH
Published: September 2010

The crystal structures of 4 α,5 α and 4 β,5 β-dihydroxyisoeremone (4) and (5), incorporating the bicyclo[2.2.2]octane skeleton, and the bicyclo[3.2.l]octane diol (6) have been determined by X-ray crystallographic methods.
Effect of Electrostatic Interactions on Effective Cross-Sections for Collision of Small Particles With Neutral Molecules
Authors: Phillips LF
Published: September 2010

Quasi-classical trajectory calculations have been used to calculate effective collision cross-sections for polar and non-polar molecules with charged and neutral conducting spheres of
radius 0.001-0.1 μm over the temperature range 10-400 K. In general the effective cross-section is much larger than the geometrical cross-section, especially for small, highly charged, particles colliding with highly polar molecules at low temperatures. The results may have a bearing on the growth of atmospheric aerosols and of interstellar dust grains.
3-O-Demethylschizopeltic Acid, a New Dibenzofuran From the Lichen Roccella hypomecha
Authors: Huneck S , Elix JA , Naidu R , Follmann G
Published: September 2010

The new dibenzofuran 3-O-demethylschizopeltic acid (2-methyl hydrogen 3-hydroxy-9-methoxy-1,7-dimethyldibenzofuran-2,6-dicarboxylate) (1) has been isolated from the lichen Roccella hypomecha, and the structure established by synthesis from schizopeltic acid (2).
The Reaction of (PPri3)2H2Cl2Ir With Phosphines: Crystal and Molecular Structures of mer-cis-(PMe2Ph)2(PPri3)-cis-Cl2HIrIII and mer-cis-(PMe2Ph)2(PPri3)-trans-Cl2HIrIII
Authors: Ditzel EJ , Robertson GB
Published: September 2010

Ambient temperature reactions of the complex (PPri3)2H2Cl2IrIV (1) with ethyl-substituted monodentate phosphine ligands are shown to yield different product types to those obtained both with methyl-substituted analogues and with phosphine itself. With the phosphines PH3 and PMe3-nPhn (n = 0, 1) there is spontaneous reaction to give the complexes mer-trans-(Ppri3)2(PR3)H-trans-Cl2IrIII, whereas with PEt3-nPhn (n = 0-2) the reaction yields mer-cis-(PR3)2(PPri3)H-trans-Cl2IrIII complexes. Under reflux the phosphines PMe3 and PMe2Ph also yield mer-cis-(PR3)2(PPri3)H-trans-Cl2IrIII complexes [PR3 = PMe3 (2), Pme2Ph (3)]. The differing course of the reactions of (1) with PMe3 and with PEt3 has permitted the synthesis of mer-(Pme3)-trans-(PPri3)(PEt3)H-trans-Cl2IrIII, the first example of an octahedral iridium complex containing three different monodentate phosphine ligands. All of the products obtained have been fully characterized by 31P and 1H n.m.r. spectroscopy. Crystal structure analyses of (3) and of its photoisomer mer-cis-(PMe2Ph)2(PPri3)H-cis-Cl2IrIII (4) have been carried out to permit comparison of the metal-ligand bonding in these complexes with that in their previously characterized, sterically less crowded, tris-PMe2Ph analogues. Summary data are as follows: (3), triclinic, Pī, a 13.414(1), b 12.062(1), c 9.077(1) Ǻ, α 79.53(1), β 88.05(1), γ 79.47(1)° [T 158�3 K], Z 2, R 0.022, Rw 0.032 (4822 reflections); (4), monoclinic, P21/n, a 19.694(1), b 15.972(1), c 9.548(1) Ǻ, β 101.45(1)° (T 293�2 K), Z 4, R 0.026, Rw 0.032 (5476 reflections). Both molecules exhibit distorted octahedral coordination of the metal atom and appreciably greater steric strain than in their (Pme2Ph)3HCl2IrIII analogues. Metal-ligand distances to the mutually trans Pme2Ph and PPri3 ligands are 2.322(1) and 2.372(1)Ǻ, respectively, for (3), and 2.359(1) and 2.406(1)Ǻ for (4), and suggest that the thermodynamically favoured cis-dichloro isomer (4) is the more strained. The preparations of the complexes (PCy3)2H2Cl2IrIV (1a) and (PCy3)2H2Br2IrIV (1b) (Cy = cyclohexyl), and their reactions with the same phosphines as used with (1), are also reported.
Peptides From Australian Frogs. The Structures of the Dynastins From the Banjo Frogs Limnodynastes interioris, Limnodynastes dumerilii and Limnodynastes terraereginae
Authors: Raftery MJ , Raftery MJ , Bradford AM , Bradford AM , Bowie JH , Bowie JH , Wallace JC , Wallace JC , Tyler MJ , Tyler MJ
Published: September 2010

The dermal glandular extracts of the tibial (calf) glands of the Australian banjo frogs Limnodynastes interioris, Limnodynastes dumerilii and Limnodynastes terraereginae each contain a different peptide, which we
have named dynastin 1, 2 and 3 respectively. The determination of the sequences of these peptides is detailed.
The Alkaloids of Ophiorrhiza cf. ferruginea
Authors: Arbain D , Lajis NH , Putra DP , Sargent MV , Skelton BW , White AH
Published: September 2010

Extraction of the aerial parts of Ophiorrhiza cf. ferruginea ( Rubiaceae ) has yielded the tertiary indole alkaloids dihydrocycloakagerine (1), 3,14-dihydrodecussine (mostuenine) (3) and tetrahydroakagerine (4), and the quaternary indole alkaloid isomalindine (5). The structures of dihydrocycloakagerine (1) and isomalindine (5) are confirmed by the X-ray method.
Arylpropanoids From Myristica castaneifolia (Myristicaceae).
Authors: Ali S , Read RW , Sotheeswaran S
Published: September 2010

The dichloromethane extract of the combined bark and heartwood of Myristica castaneifolia A. Gray ( Myristicaceae ) has yielded a new arylalkanone, named castanone (1), two structurally related, open-chain arylalkanones (2) and (3), and three benzofuranoid neolignans (4)-(6). The known antibacterial activity of the neolignans accounts for the antidiarrhoeal property of M. castaneifolia.
Viscosity Data and Viscous Flow Thermodynamics of 2-Methoxyethanol+ Water Binary Mixtures
Authors: Corradini F , Marchetti A , Tagliazucchi M , Tassi L , Tosi G
Published: September 2010

Kinematic viscosities (v) have been measured for pure 2-methoxyethanol, pure water, and nine of their mixtures over the entire composition range and, where possible, at 19 temperatures ranging from -10 to +80°C. The above property was fitted by empirical equations stating its dependence on temperature (T) and mole fraction (X1) of the mixtures. The experimental data for the binary mixtures were used to test the validity of mixing rules at different temperatures.
Anionopentaaminecobalt(III) Complexes With Polyamine Ligands. XXVI. Spontaneous and Hg2+-Assisted Chloride Release Kinetics From Some CoCl(tacn)(diamine)2+ Complexes
Authors: House DA , Vaneldik R
Published: September 2010

The rate of spontaneous ( kH ) and Hg2+ assisted ( kHg ) chloride release from some CoCl ( tacn )( diamine )2+ complexes [ tacn = 1,4,7-triazacyclononane; diamine = ethane-1,2-diamine (en), propane-1,3-diamine ( tn ), 2-aminomethylpyridine ( ampy )] have been measured in acidic aqueous solution as a function of temperature and pressure. Rate constants (at 25.0°C), ΔH‡ (kJ mol-1), ΔS‡ (J K-1 mol-1), ΔV‡ (cm3 mol-1) are: 106 kH (en) = 1.63 (s-1), 93, -44, -3.6; 106kH ( tn ) = 1.86 (s-1), 92, -47, -4.5; 106kH ( ampy ) = 0.343 (s-1), 103, -22; 103kHg (en) = 11.0 (dm3 mol-1 s-1), 74, -32, +1.44; 103kHg ( tn ) = 54.0 (dm3 mol-1 s-1), 77, -13, +3.26; 103kHg ( ampy ) = 10.2 (dm3 mol-1 s-1), 76, -30, +0.86. The normal accelatory influence observed when en is replaced by tn is very weak in these structurally rigid tacn systems.
Investigation of the Structures of Some Natural Products From the Neem Tree
Authors: Bendall JG , Cambie RC , Rutledge PS , Woodgate PD
Published: September 2010

Podocarpic acid (1) and totarol (2) have been converted into five diterpenoids reported to have been isolated from the Neem tree. The synthetic diterpenoids have been compared with the naturally occurring diterpenoids but only the structure of nimbidiol (23) has been confirmed. The structure for margosolone, which was reported as (19), has been revised to (20) after synthesis of both (19) and (20).
Jones Oxidation of 20-Hydroxyecdysone (Crustecdysone)
Authors: Petersen QR , Cambie RC , Russell GB
Published: September 2010

Oxidation of 20-hydroxyecdysone ( crustecdysone ) (4) with Jones reagent gives a 2:1 mixture of posterone (1) and its 3-keto derivative (2). A possible source of (2) is suggested.
Intramolecular Trapping of a Ketenimine Carbene Formed on Flash Vacuum Pyrolysis of 3-Phenylimino-3H-indazole and 3-Phenyliminoisobenzofuran-1-one
Authors: Brown RFC , Coulston KJ , Eastwood FW
Published: September 2010

Flash vacuum pyrolysis of 3-phenylimino-3H-indazole yielded biphenylene , benzonitrile and, by loss of dinitrogen followed by intramolecular trapping of a ketenimine carbene intermediate, the isomers fluorenimine , phenanthridine and 2-phenylbenzonitrile.Pyrolysis of 3-phenyliminoisobenzofuran-1-one gave the same five products together with N- phenylphthalimide . It is proposed that the same ketenimine carbene intermediate is involved in the two reactions. Pyrolysis of 3-o-tolylimino- and 3-benzylimino-isobenzofuran-1-one led to fragmentation without intramolecular trapping. Pyrolysis of 3-t-butyliminoisobenzofuran-1-one gave o-cyanobenzoic acid.