bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiments Directed Towards the Synthesis of Anthracyclinones. X. A Synthesis of (±)-4-Demethoxydaunomycinone
Authors: Cambie RC , Larsen DS , Rickard CEF , Rutledge PS , Woodgate PD
Published: September 2010

The acetal methyl 2-(3-dimethoxymethyl-4-hydroxy-1-methoxy-9,10-dioxo- 9,10-dihydroanthracen-2-yl)acetate (2), a versatile intermediate prepared earlier from quinizarin (1), has been converted into (�)-4- demethoxydaunomycinone (5) in 43% yield (on a small scale) from the acetal (2) and in 29% overall yield from quinizarin. The structure of (�)-9α-acetyl-6,9-dihydroxy-7α,11-dimethoxy-5,7,8,9,10,12-hexahydronaphthacene-5,12-dione (6), an intermediate in the sequence, has been confirmed by X-ray studies.
Magnetic and Spectroscopic Studies on Copper(II) and Chromium(III) Complexes With Sulfur Chelating Ligands
Authors: Fabretti AC , Preti C , Tassi L , Tosi G , Zannini P
Published: September 2010

A number of complexes of chromium(III) and copper(II) with heterocyclic dithiocarbamate ligands is reported. The newly prepared compounds are characterized on the basis of near- i.r . and far- i.r . spectroscopy, electronic and e.p.r . spectra, conductivity measurements and magnetic moment studies at different temperatures. The dithio ligands exhibit bidentate behaviour acting as S,S′-donors in all the complexes. The chromium(III) compounds have g values in the 1.991-1.999 range and nephelauxetic parameters indicative of an appreciable metal- ligand covalency. The e.p.r . data of the copper(II) derivatives provide parameters typical of sulfur coordination in planar CuS4 chromophores ; the α bonding parameters are indicative of strongly covalent metal- ligand interactions.
The Interconversion of the Lichen Depsides Para- and Meta-Scrobiculin, and the Biosynthetic Implications
Authors: Elix JA , Gaul KL
Published: September 2010

An equilibrium mixture of the isomeric depsides para- and meta- scrobiculin has been extracted from the lichen Lobaria scrobiculata. Acetylation of this mixture led to the isolation of two isomeric triacetates, the structures of which were confirmed by unambiguous synthesis. This equilibration provides compelling evidence that m-depsides arise biogenetically by C-hydroxylation of the B-ring of a p-depside followed by an intramolecular rearrangement.
Intramolecular Diels-Alder Additions of Benzynes to Furans. Exploratory Studies
Authors: Best WM , Wege D
Published: September 2010

A series of 3-alkoxyanthranilic acids, in which a furan ring is attached to the terminal carbon atom of the alkoxy group, has been prepared. When the chain linking the anthranilic acid and furan ring systems is three or four atoms long, decomposition of the derived diazonium chlorides generates the corresponding benzynes , which are efficiently trapped intramolecularly by the furan moiety. Diazotization of 2-amino-3-furfuryloxybenzoic acid, where the linking chain is two atoms long, results in fragmentation with the formation of 6-diazo-5- oxocyclohexa-1,3-diene-1-carboxylic acid.
The Interaction of Cobalt(II), Nickel(II), Copper(II) and Zinc(II) With Oxygen-Nitrogen Donor Macrocycles Immobilized on a Polystyrene Matrix
Authors: Paredes RS , Valera NS , Lindoy LF
Published: September 2010

Five macrocyclic ligands incorporating O2N2 or O2N3 donor sets have been appended to 2% crosslinked polystyrene, and the metal-ion-binding properties of the resulting functionalized polymers towards CoII , NiII, CuII and ZnII have been investigated. Loading studies were undertaken in ethyl acetate/methanol (9 : 1), and, under similar conditions, the degree of loading was found to be metal-dependent. In addition, in some cases metal uptake was found to exceed that required for 1:1 complexation of metal to cyclic ligand . In the above solvent mixture, metal-exchange reactions were found to be relatively facile. However, attempts to leach metal ions from the loaded polymers with either acid or ammonia in aqueous media were less successful due to poor swelling of the polymer beads in such media. Matrix effects associated with the polystyrene backbone appear to be the cause of the significant modification in metal-ion-binding properties of the immobilized macrocycles relative to those of their detached analogues.
A Simple and Efficient Preparation of Penicillin V β-Sulfoxide
Authors: Davis M , Wu WY
Published: September 2010

Penicillin V (1) can be oxidized to the β- sulfoxide (2) in high yield in a two-phase mixture of dichloromethane and aqueous hydrogen peroxide. The addition of acids or metallic catalysts is not necessary.
Some Substituent Effects in the Formation of Binuclear Metalladienes and 1,2-Dimetallacycloheptadienones From Reactions Between (η-C5H5)2Rh2(μ-CO)(CF3C2CF3) and Alkynes
Authors: Baimbridge CW , Dickson RS , Fallon GD , Grayson I , Nesbit RJ , Weigold J
Published: September 2010

The reaction between (η-C5H5)2Rh2(CO)(CF3C2CF3)(1) and alkynes, RC=CR′, can proceed by two alternative pathways. One gives the complexes (η- C5H5)2Rh2{C4(CF3)2RR′CO} (2) in which a pentadienone unit bridges the Rh - Rh bond. The other produces
the binuclear metalladiene complexes (η-C5H5)2Rh2{C4(CF3)2RR?} (3) plus the dicarbonyl complex (η-C5H5)2Rh2(CO)2(CF3C2CF3) (4). The formation of (2) is strongly favoured with the dialkylacetylenes BuC≡CBu and MeC =CR (R = Et, Pri, But). With the unsymmetrical acetylenes, two isomers of (2) are isolated. The tendency to form (3) + (4) increases when there are electron-withdrawing substituents such as CN on the alkyne, and becomes dominant when the alkyne is polar (e.g. MeC≡CR with R = Ph, CF3 or CO2Me). The reactions with MeC≡CR are highly regioselective, with only one of the two possible regioisomers being isolated in each case. This has the methyl group in the 3-position of the metalladiene ring. Unexpected products formed in the reactions with MeC≡Cet and MeC≡CPri have been characterized by X-ray crystallography. One is a 1,2- dimetallacycloheptadienone complex, (η-C5H5)2Rh2{C4(CF3)2Me(CMe2OH)CO}. The compound crystallizes with 16 molecules in the orthorhombic space group Fdd2 in a unit cell of dimensions a 31.728(15), b 27.923(14), c 9.275(5) Ǻ. The structure was solved by heavy atom methods and refined to R 0.037 based on 2644 observed reflections. The CMe2(OH) group is adjacent to the carbonyl in the bridging group. The other is a binuclear metalladiene complex (η-C5H5)2Rh2{C4(CF3)2Me( COMe )}. It crystallizes with eight molecules in the orthorhombic space group P bca in a unit cell of dimensions a 17.349(8), b 15.819(8), c 13.720(7) Ǻ. The structure was solved by heavy atom methods and refined to R 0.053 based on 3045 observed reflections above background. The acyl group is adjacent to the metal in the metalladiene ring. These two complexes are formed from (1) and impurities present in the alkynes.
Metal Template Reactions. XXII. General-Synthesis of Dibenzocorromins and Related Nickel(II) Complexes
Authors: Black DSC , Brockway DJ , Moss GI
Published: September 2010

The macrocyclic nickel(II) complexes (9)-(11) have been prepared by metal template methods from the dialdehydes (7), which in turn have been derived from the bis-isatins (4). Complexes (9)-(11) have undergone oxidative dehydrogenation to the complexes (12)-(14). The effect of various substituents is discussed.
Naturally-Occurring Dibenzofurans. VIII. The Synthesis of Isodidymic Acid
Authors: Carvalho CF , Sargent MV
Published: September 2010

The synthesis of the lichen dibenzofuran isodidymic acid (2)(3-hydroxy- 7-methoxy-9-pentyl-1-propyldibenzofuran-2-carboxylic acid) by intramolecular Ullmann coupling of methyl 3-iodo-4-(2′-iodo-5′-methoxy- 3′-pentylphenoxy)-6-methoxy-2-propylbenzoate (22), and further transformations, is described.
The Rate-Constant of the Reaction of Hydroxyl Radicals With Methanol, Ethanol and (D3)Methanol
Authors: Greenhill PG , Ogrady BV
Published: September 2010

The rate coefficients for hydrogen abstraction by hydroxyl radicals from methanol and ethanol have been determined in the temperature ranges 260-803 K and 255-459 K respectively. Flash photolysis combined with resonance absorption detection of OH was used to obtain results which may be described by the Arrhenius expressions:   Methanol ��� k(T) = (8.0�1.9)×10-12 exp[-(664�88)K/T]cm3 s-1 ������� (1)   Ethanol ���� k(T) = (1.25�0.24)×10-11 exp[-(360�52)K/T]cm3 s-1 (2)  The results obtained for methanol are in excellent agreement with results obtained by other workers, but the Arrhenius parameters for ethanol are markedly different to those obtained in the only other study of the temperature dependence of this reaction. The rate constant for reaction with (D3)methanolhas been determined at 293 K: (D3)Methanol ����� k(293) = 5.0�0.2×10-13 cm3 s-1 (3) The presence of an isotope effect confirms that the predominant process is abstraction of hydrogen from the carbon rather than the oxygen. The results obtained for the reaction with ethanol were analysed by using a 21 reaction scheme to determine the effect of [OH]O and secondary reactions on k(T). The simulations indicate that secondary reactions involving OH are relatively unimportant in determining the bimolecular rate coefficients found in this study.
Studies in the Cycloproparene Series: 1,1-Dichloro-1h-Cyclopropa[l]Phenanthrene
Authors: Dent BR , Halton B
Published: September 2010

Phenanthrenes (5c-e) substituted at the 9-position with sulfur or selenium undergo addition of dichlorocarbene to provide the corresponding 1a-substituted 1a,9b-dihydro-cyclopropa[l]phenanthrenes (6c-e). Oxidation of the phenylselenocyclopropaphenanthrene (6e) followed by selenoxide elimination provides products resulting from cleavage of the three-membered ring. Complementary deuterium labelling studies show that the major pathway for this elimination proceeds via 1,1-dichloro-1H-cyclopropa[l]phenanthrene (4b).
3,10-Dihydroxydielmentha-5,11-Diene-4,9-Dione. A Diterpenoid (Bismonoterpenoid) With a Novel Carbon Skeleton
Authors: Carman RM , Lambert LK , Robinson WT , Vandonge n
Published: September 2010

3,10-Dihydroxydielmentha-5,11-diene-4,9-dione, a diterpenoid (C20H28O4) from Callitris macleayana heartwood, is shown by degradation, by both one- and two-dimensional high-field n.m.r. exploration, and by X-ray crystallographic analysis to have a unique carbon skeleton formally based upon the Diels-Alder self- dimerization of a p- menthadienone.
Molten Potassium Pyrosulfate: Reactions of Five Alkali-Metal Salts of Sulfur Oxo Acids
Authors: Mineely PJ , Tariq SA
Published: September 2010

The reactions of five alkali-metal salts of sulfur oxo acids with molten K2S2O7 were investigated. Na2SO3, Na2S2O3, Na2S2O4, Na2S2O5 and K2S2O3 reacted with molten K2S2O7 to form sulfate, elemental sulfur and SO2 as the final reaction products. Reaction pathways have been postulated to explain the final products. The stoichiometries of the reactions have been determined.
Relaxation Processes in Aromatic Methyl-Groups. I. 2-Chloro-Toluene and 2,6-Dichloro-Toluene
Authors: Craik DJ , Drew RM , Kyratzis I , Rae ID , Weigold JA
Published: September 2010

Three series of selectively deuterated toluenes, 2-chlorotoluenes and 2,6-dichlorotoluenes have been synthesized, and their methyl group 1H n.m.r. relaxation pathways have been determined by 1H, 2H and 13C n.m.r. spin-lattice relaxation time measurements. 1H spin-lattice relaxation in the methyl groups of these series occurs predominantly through an intramethyl H-H dipolar mechanism as well as through the spin-rotation mechanism. Dipolar spin-lattice relaxation rates for intramethyl H-H pairs are 0.012, 0.020 and 0.025 s-1 for toluene, 2,6-dichlorotoluene and 2-chlorotoluene respectively, suggesting a decrease in the rate of methyl group rotation in this order. Ab initio molecular orbital calculations on the same compounds show that the theoretically predicted barrier to methyl group rotation increases in the order toluene < 2,6-dichlorotoluene < 2-chlorotoluene, supporting the experimentally derived results.
Synthesis and Structure-Activity Studies of Potential Antitumor Agents Derived From Esters of Phorbol
Authors: Tyler MI , Howden MEH
Published: September 2010

A synthetic study was carried out aimed at elucidating structure-activity relationships amongst naturally occurring esters of phorbol (la) and related daphnane ortho esters which have antitumour activity. The following phorbol esters and epoxy derivatives were prepared with ester groups which were present in the structurally related antitumour natural products: the 12,13,20-tribenzoate (lb), 12,13-dibenzoate ( lc ), 12,13-dibenzoate 20-palmitate (Id), 13-acetate 12,20-dibenzoate (le) and the 12,13,20-tricinnamate (1f of phorbol , and the 6,7-epoxides of the 12,13-dibenzoate (2a) and the 12,13,20-tricinnamate (2b) of phorbol . These compounds were tested against in vivo P388 murine lymphocytic leukaemia (3PS) and were found to have low activity. Various combinations of ester and epoxy groups alone were found to be insufficient to confer 3PS activity on the compounds studied. It was concluded that the presence of other groups, such as a 5-hydroxy group, an ortho ester function, and opening of the cyclopropane ring may be important in enhancing this activity.
Anthracyclines. XVI. Further Comments Concerning the Phthalide Anion Annelation of Quinone Monoacetals
Authors: Russell RA , Pilley BA , Irvine RW , Warrener RN
Published: September 2010

.Yields of tricyclic and tetracyclic quinones prepared by annelation of quinone monoacetals with the anion of 3-phenylsulfonylphthalides are shown to be sensitive to the substituent on both the phthalide and the quinone monoacetal partner. In contrast, reactions with the anions of 3-cyanophthalides afford high yields of condensed products in all cases examined.
The Synthesis of 3,10-Dihydroxydielmentha-5,11-diene-4,9-dione
Authors: Carman RM , Owsia S , Vandonge n
Published: September 2010

A synthesis is reported for the title compound.
Constituents of the Zingiberaceae. X. Diastereomers of [7-Hydroxy-5-Methoxy-2-Methyl-2-(4′-Methylpent-3′-Enyl)-2H-Chromen-8-yl] [3″-Methyl-2′-(3′″-Methylbut-2″′-Enyl]-6″-Phenylcyclohex-3″-Enyl]M Ethanone (Panduratin B), a Constituent of the Red Rhizomes of a Variety of Boesenbergia pandurata
Authors: Pancharoen O , Picker K , Reutrakul V , Taylor WC , Tuntiwachwuttikul P
Published: September 2010

Spectroscopic studies have established that panduratin B1 and panduratin B2, isolated from the red rhizomes of a variety of Boesenbergia pandurata ( Roxb .) Schltr ., are the diastereomers (2RS,1″ RS,2″SR,6″RS)- and (2RS,1″SR,2″RS,6″SR)-[7-hydroxy-5-methoxy-2-methyl-2-(4′-methylpent-3′-enyl)-2 H-chromen-8-yl][3″-methyl-2″-(3″′-methylbut-2″′-enyl)-6″-phenylcyclohex-3″-enyl]methanone. A synthesis of panduratin B mixture has been achieved by chromenylation of panduratin A.
On the Electrochemical Behavior of Pyrylium Ions at the Mercury-Electrode. III. Adsorption Behavior at the Aqueous-Mercury Interface
Authors: Garrard WNC , Thomas FG
Published: September 2010

The adsorption behaviour of four pyrylium ions-2,4,6-trimethylpyrylium, 2,4,6-tri-t- butylpyrylium , 2,4,6-triphenylpyrylium and 7-phenyl-5,6,8,9-tetrahydrodibenzo[ c,h ] xanthylium -at the mercury-aqueous 0.5 M sulfuric acid interface is reported. The 2,4,6-trimethylpyrylium ion shows little tendency to adsorb at the mercury interface even at concentrations approaching saturated solution. The tri-t- butylpyrylium ion is adsorbed in a vertical orientation on a positively charged electrode, while on a negatively charged electrode it exhibits two position adsorption- initially flat then reorienting to vertical at higher concentrations. Triphenylpyrylium ions form an adsorbed layer of vertically oriented ions which approaches monolayer coverage at potentials just prior to its reduction at -0.68 V. The product of the reduction inhibits the reduction of the parent ion. The xanthylium ion behaves in a similar manner to the tri-t-butyl ion but the conclusions are tentative due to the limited reliability of the data as a consequence of the low solubility of this ion in water.
Heterocyclic Variants of the Purine System. II. Derivatives of Thiazolo[4,5-E]-1,2,4-Triazines, a New Heterocyclic Ring System
Authors: Jacobsen NW , Philippides AE
Published: September 2010

.Some representative derivatives of the new thiazolo [4,5- e]-1,2,4-triazine ring system were prepared from 5-acylamino-1,2,4-triazin-6(1 H)-ones by heating with phosphorus pentasulfide in pyridine. Further derivatives of the biheterocyclo system were also made from 6-methylthio-1,2,4-triazin-5-amines by heating with carbon disulfide or phenyl isothiocyanate.
1,2,4-Triazines. II. New Zwitterionic Methylation Products of Some 1,2,4-Triazin-5(2H)-Ones and Their Identification by Carbon-13 Nuclear Magnetic Resonance Spectroscopy
Authors: Jacobsen NW , Rose SE
Published: September 2010

The methylation of various 3-and 6-substituted 1,2,4-triazin-5(2H)-one derivatives yield new zwitterionic N1 methylation products in addition to the previously reported 2-, 4- and Omethyl isomers. Specifically, 3-phenyl-1,2,4-triazin-5(2H)-one and its 6-methyl and 6-phenyl derivatives gave 1-methyl-3-phenyl-1,2,4-triazinium-5-olate, 1,6-dimethyl-3-phenyl-1,2,4-triazinium-5-olate and l1methyl-3,6-diphenyl-1,2,4-triazinium-5-olate, respectively, upon methylation. A new hindered derivative, 3,6-di-t-butyl-l,2,4-triazin-5(2H)-one, did not yield a zwitterion upon methylation but instead gave the 2- and Omethyl isomers. In all cases, carbon-13 nuclear magnetic resonance spectroscopy employing both proton-coupled and -decoupled spectra was used to identify the sites of methylation.
Irreducible Representations for Cyclic, Dihedral and Cubic Point Groups
Authors: Rodger A
Published: September 2010

A method for deriving the matrix irreducible representations for cyclic, dihedral and cubic groups purely from the structure of the group multiplication table is presented. Full irreducible representations for D∞h and O are given, from which those for all cyclic, dihedral and cubic groups can simply be derived.
Photooxidation of Tetrabromofuran in Benzene
Authors: Shoppee CW , Wu WY
Published: September 2010

Photooxidation in the solid state of tetrabromofuran (1) gave the tetrabromo -γ-lactone (2) (30%), but in benzene solution gave dibromomaleic anhydride (3) (85%). Possible radical chain mechanisms for the transformations (1) → (2) and (1) → (3) are suggested. A molecular orbital discussion attempts to explain how an initial π-π* transition of a C=C bond in (1) leads to a σ C-Br bond fission. Use of e.p.r . to detect radicals in the transformations (1) → (2) and (1) → (3) failed.
Structure and Magnetism of Cs2KCr(CN)6 at Very Low Temperatures
Authors: Brown PJ , Figgis BN , Forsyth JB
Published: September 2010

The structure of the elpasolite Cs2KCr(CN)6 has been determined at 7.0 K by neutron diffraction. 877 unique reflections refined to Rw = 0.020, Χ = 1.4. The Cr(CN)6 unit is close to regular octahedral coordination geometry, with bond lengths of 207.4(4) for Cr-C and 116.6(6) pm for C-N. The C-Cr-C angles average to 90.0(5)� and the Cr-C-N angles to 178.3(1)�. The magnetic susceptibility as a function of temperature and the magnetization as a function of magnetic field strength correspond to the 4A2g ground term perturbed by a small magnetic exchange effect.
Preparation and Structure of Tetraphenylarsonium Bis(Benzene-1,2-Dithiolato)Oxotechnetate(V)
Authors: Colmanet SF , Mackay MF
Published: September 2010

The reaction of benzene-1,2-dithiol (bdtH2) with [AsPh4] [TcOCl4] in aqueous alcohol yields crystals of [AsPh4] [ TcO ( bdt )2] (1) from acetonitrilelethanol. The crystal structure of (1) has been determined by X-ray diffraction and found to be isostructural with [PPh4] [ MoO ( bdt )2]. Crystals art monoclinic and belong to the space group Cc with a 12.652(1), b 15.783(1), c 16.622(1) �, β 93.03(1)� with Z 4. Refinement on 2828 diffractometer data measured with Cu Ka radiation converged at R 0.030. The structure consists of [ TcO ( bdt )2]- anions and [AsPh4]+ cations. The technetium(V) atom is five-coordinate, with the four sulfur atoms in the basal positions and the oxo ligand in the apical position, to give a distorted square-pyramidal environment about the technetium.
The Synthesis of Phosphonobaclofen, an Antagonist of Baclofen
Authors: Chiefari J , Galanopoulos S , Janowski WK , Kerr DIB , Prager RH
Published: September 2010

Phosphonobaclofen, 3-amino-2-(4-chlorophenyl) propylphosphonic acid, has been synthesized in five steps from ethyl 3-(4-chloropheny1)but-2-enoate, and is a specific antagonist of baclofen . Two alternative synthetic pathways, involving conjugate addition of phosphite to 2-(4-chlorophenyl) propenenitrile and of cyanide to 2-(4-chlorophenyl) ethenylphosphonate ester, failed. Cyanide ion did add efficiently to ethyl 3-(4-chloropheny1)-2-diethoxyphosphinylprop-2- enoate, and hydrogenation followed by hydrolysis of the product gave (2S,3S)- and (2R,3R)-4-amino-3-(4-chloropheny1)-2-phosphonobutanoic acid, which is also undergoing pharmacological evaluation.
New Depsides From Erioderma Lichens
Authors: Elix JA , Mahadevan I , Wardlaw JH , Arvidsson L , Jorgensen PM
Published: September 2010

A chemosyndrome of para- depsides based on methyl 4-O-demethylbarbatate (3) has been detected in Erioderma lichens and the structures of the metabolites have been established by unambiguous syntheses. New depsides include methyl 5-chloro-4-O-demethylbarbatate (4), methyl eriodermate (5), methyl 2'-0-methyleriodermate (6), methyl 2-O-methyleriodermate (7), methyl 4-O-methyleriodermate (8) and methyl 2,2'-di-O-methyleriodermate (9).
The 1,2-Didehydronaphthalene to 1H-Indenylidenecarbene Rearrangement: Formation of 7-Methyl-1H-Indenylideneethenone and Its Rearrangement to Acenaphthylen-4-Ol in a Flash Vacuum Pyrolytic Reaction
Authors: Brown RFC , Coulston KJ , Dobney BJ , Eastwood FW , Fallon GD
Published: September 2010

7-Methyl-1 H- indenone was trapped as the cyclopentadiene adduct endo* 8-methyl-1,4,4a,9a tetrahydro-1,4-methano-9H-fluoren-9-one (11) which was converted into the E- and Z-isomers (15) and (16) of endo (8'-methyl-l',4',4a',9a'-tetrahydro-1',4'-methano-9'H-fluoren-9'-ylidene) ethanoic acid by addition of methoxyethyne, rearrangement and hydrolysis. Both acids yielded the anhydride (17) of the E-acid on treatment with trifluoroacetic anhydride. Flash vacuum pyrolysis of this anhydride at 650� gave acenaphthylen-4-ol. 7-Methyl-1 H- indenylideneethenone (7) is proposed as an intermediate in this reaction and the results are discussed in relation to the rearrangement described in the title. The X-ray crystal structure of methyl endo (E)-(8'-methyl-l',4',4a',9a'-tetrahydro-l',4'-methano-9'H-fluoren-9'-ylidene) ethanoate (13) is reported.
Reactions of Dimethyl (2'-Oxopropylidene)Propanedioate and Dimethyl (3'-Bromo-2'-oxopropylidene)propanedioate, Two Highly Electrophilic Trisubstituted Alkenes
Authors: Cameron DW , Read RW , Stavrakis J
Published: September 2010

The keto diester, dimethyl (2'-oxopropylidene)propanedioate, and its new 3'-bromo derivative have been made to react with a variety of nucleophilic reagents. Low molecular weight products have been obtained efficiently by processes involving conjugate addition, Diels-Alder reaction, Diels-Alder reaction having inverse electron demand, or ene reaction. Regiochemistry of the reactions is controlled by the dominant withdrawing effect of the two geminal ester groups. The amine addition products of the bromo keto diester were found to undergo a novel secondary dehydrobromination reaction under alkaline conditions.
Synthetic Confirmation of the Structure of the Lichen Benzyl Esters Alectorialic and Barbatolic Acids
Authors: Elix JA , Jayanthi VK
Published: September 2010

The total synthesis of methyl alectorialate (3) and methyl barbatolate (4) has been achieved, and the synthetic esters have been compared with naturally derived material. In addition alectorialin (decarboxylalectorialic acid) (5) and barbatolin (6) have been synthesized. The lichen Alectoria nigricans was shown to contain alectorialic acid (1), barbatolic acid (2), alectorialin (5) and 5,7-dihydroxy-6-methylphthalide (8), while the lichen Bryoria nadvornikiana was found to contain (1), (2), (5), barbatolin (6) and 6-formyl-5,7-dihydroxyphthalide (27).
Oxidation of Amino Acids. IV. Reaction of Dibenzoyl Peroxide With ω-Amino Acid Esters
Authors: Milewska MJ , Chimiak A
Published: September 2010

N-Acetyl N-benzoyloxy ω-amino acid esters were obtained by the oxidation of the ester amine group with dibenzoyl peroxide and subsequent acetylation. The yield of the desired product increased with the length of the carbon chain.
13C N.M.R. Spectra of ortho-Substituted Phenyl N,N-Dimethyl-Carbamates and N-Methyl Carbamates
Authors: Yamagami C , Sai T , Takao N
Published: September 2010

We measured 13C nuclear magnetic resonance spectra of O-substituted phenyl N,N- dimethyland N-methyl- carbamates and compared the results with those for the corresponding m- and p-substituted derivatives. The additivity relationship on the basis of the substituent chemical shift for monosubstituted benzenes ( scsphx ) did not hold well because of the ortho effect. However, the scs of C2(ipso), C3(ortho) and C5(para) was correlated excellently with scsphxX . Dual substituent parameter (DSP) analyses of the scs of C5 and the carbonyl carbon in the fixed side chain showed that correlation was very good for C5 but moderate for C=O. These observations suggested that the X substituent lay in almost the same plane as the aromatic ring, whereas the OCONMe2 group may have changed its conformation somewhat. In O-substituted derivatives, the carbon nucleus that is directly attached to the aromatic ring (γ to the oxygen; OCONMe2)had a pronounced upfield shift relative to the corresponding m- and p-substituents by 4-5 ppm . This phenomenon was explained by the γ-effect caused by the oxygen atom.
The Thermal ortho-Substitution of Phenols by Vinyl Ethers
Authors: Pinhey JT , Xuan PT
Published: September 2010

Pyrolysis of a mixture of phenol and 3,4-dihydro-2H-pyran (6) at 150- 180°C resulted in the formation of 2-(tetrahydro-2H-pyran-2-yl)phenol (3a) in moderate yield. This selective ortho-substitution reaction has been investigated for a range of phenols and a number of vinyl ethers. While it was found to be a fairly general reaction for phenols, only with the vinyl ether (6) and 2,3-dihydrofuran (28a) was the reaction found to be regioselective. Aluminium phenylate strongly catalyses the reaction of phenol with (6), which proceeded under these conditions at room temperature. An ene -type mechanism is proposed for the reaction.
The Reaction of 1-Methylperimidine With Lithium Diisopropylamide: Evidence for a Radical Anion Intermediate
Authors: Denny WA , Herbert JM , Woodgate PD
Published: September 2010

The reaction of 1-methylperimidine with lithium diisopropylamide in tetrahydrofuran gives a product indicative of a radical anion intermediate.
Phenolic Analogs of Amino Carboxylic Acid Ligands for 99mTc. II. Synthesis and Characterization of N,N'-Ethylenebis[N-(o-Hydroxybenzyl)-glycines] (ehbg)
Authors: Wilson JG
Published: September 2010

Ten N,N,- ethylenebis [N-(o- hydroxybenzyl ) glycines ] ( ehbg ), eight of them new, have been synthesized and characterized by their i.r ., 1H n.m.r . and f.a.b, mass spectra and by conversion of their dimethyl ester dihydrochlorides.
Nitrones and Oxaziridines. XXXVII. Some Oxidation Reactions of 1-Pyrroline 1-Oxides
Authors: Black DSC , Strauch RJ
Published: September 2010

The 2,4-diaryl-1-pyrroline 1-oxides (4) can be converted into the related 2H-pyrrole 1-oxides (5) by treatment with N-bromosuccinimide and anhydrous potassium carbonate. Similar treatment of the 1-pyrroline 1-oxide (6) yielded the succinimido-substituted pyrroline (7). Selenium dioxide oxidation of the tetramethyl nitrone (8) under various conditions gave mixtures containing the compounds (10)-(12). Neither process provides a general conversion of 1-pyrroline 1-oxides into 2H-pyrrole 1-oxides.
Synthesis of Precursors Suitable for Pyrolytic Fragmentation to Pentatetraenone
Authors: Brown RFC , Coulston KJ , Eastwood FW , Hill MP
Published: September 2010

Reaction of 2-phenylselenopropanoyl chloride with methyl ( triphenylphosphoranylidene ) ethanoate yielded methyl 4- phenylselenopenta-2,3-dienoate (3). Distillation of the ester (3) gave dimethyl (E,E)-3′,4′-dimethylcyclobut-3′-ene-1′,2′- diylidenebisethanoate (5) and oxidation of (3) with potassium peroxymonosulfate yielded methyl 2-oxopent-3-ynoate (8). The ester (3) with cyclopentadiene at 160-180° gave a Diels-Alder adduct methyl 3- (1′-phenylselenoethylidene) bicyclo [2.2.1]hept-5-ene-2-carboxylate (4) as a mixture of four isomers. Treatment of the mixture with lithium diisopropylamide and methyl chloroformate yielded a mixture of two isomers of dimethyl 3-(1′-phenylselenoethylidene) bicyclo [2.2.1]hept-5- ene-2,2-dicarboxylate (16). Oxidation of the monoester (4) and the diester (16) with m-chloroperbenzoic acid gave the corresponding selenoxides which on thermal elimination in boiling tetrachloromethane /potassium carbonate gave endo/exo methyl 3-ethenylidenebicyclo [2.2.1]hept-5-ene-2-carboxylate(10) and dimethyl 3-ethenylidenebicyclo [2.2.1]hept-5-ene-2,2-dicarboxylate (18). Hydrolysis of these esters with lithium hydroxide gave 3-ethenylidenebicyclo [2.2.1]hept-5-ene-2-carboxylic acid (12) as a mixture of endo/exo isomers and 3-ethenylidenebicyclo[2.2.1]hept-5- ene-2,2-dicarboxylic acid (19). The diacid (19) was treated with HC=C- OEt , HC=C- OMe , Me2Si(O-C( OMe )=CMe2)2 and with (CF3CO)2O to give compounds (20)-(23) as expected pyrolytic precursors of pentatetraenone. The mixture of monoacids (12) was also treated with (CF3CO)2O to give mixed anhydride (13). The 13C-carboxyl labelled acid (12′) was similarly converted into the labelled mixed anhydride (13′) as a pyrolytic precursor of H2C=C=C=C=13C=O. The following paper reports an argon matrix infrared spectroscopic study of the pyrolysates from compounds (13), (13′), (21), (22) and (23).
The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)
Authors: Robertson GB , Tucker PA
Published: September 2010

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a
27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.
The Treatment of Some Carbohydrate Alcohols and Diols With N-Dibromomethylene-N,N-Dialkylammonium Bromides: a Synthesis of Glycosyl Bromides
Authors: Mcadam DP , Stick RV
Published: September 2010

Two analogues of Viehe's salt (Me2N+=CCl2Cl-), namely Me2N+=CBr2 Br- and Et2N+=CBr2 Br-, were prepared and treated with various carbohydrate alcohols and diols. With the diols, the products formed corresponded to those previously obtained with Viehe's salt itself, namely bromo deoxy sugars, cyclic carbonates or carbamates, and depended on the nature of the substrate and the reaction conditions. With the alcohols, mainly free sugars, a useful synthesis of glycosyl bromides was achieved.
Cyclopentadienyl-Ruthenium and -Osmium Chemistry. XXX. Synthesis and X-Ray Structure of [Ru(dppm-P)(dppm-P,P')(η-C5H5)][PF6]0.5[PO2F2]0.5
Authors: Bruce MI , Cifuentes MP , Grundy KR , Liddell MJ , Snow MR , Tiekink ERT
Published: September 2010

An improved, one-pot synthesis is reported for the [Ru (dppm -P)(dppm -P, P′)(η-C5H5)]+ cation as its BF4- salt. The crystal structure of [Ru ( dppm - P)( dppm -P,P′)(η-C5H5)]+, obtained as the mixed PF6-/PO2F2- salt, has also been determined. There are few differences in dimensions between the mono- and bi-dentate dppm ligands; chelation sharply reduces the P-CH2-P angle, and one phenyl group on each phosphorus is bent away from the metal. Crystals are monoclinic, space group C2/c with unit cell dimensions a 21.743(3), b 23.594(3), c 21.352(3)Ǻ, β 110.17(1) and Z 8. The structure was refined by a full-matrix least-squares procedure to final R 0.078 and Rw 0.087 for 4490 reflections with I > 2.5σ(I).
1,2,4-Triazines. IV. The Structural Elucidation of Some New N-Methyl 3-Amino-1,2,4-Triazin-5(2H)-ones by Carbon-13 Nuclear Magnetic Resonance Spectroscopy
Authors: Jacobsen NW , Rose SE
Published: September 2010

Methylation of 3-amino-1,2,4-triazin-5(2H)-one yields a mixture of the zwitterion 3-amino-1-methyl-1,2,4-triazinium-5-olate and 3-amino-2- methyl-1,2,4-triazin-5(2H)-one. With appropriate substituents located at position C6 and on the exocyclic amino group at C3, methylation was directed to the N1 or N2 positions exclusively. All methylation isomers were identified by carbon-13 nuclear magnetic resonance spectroscopy by reference to long-range coupling patterns.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. XXXVII. A Novel Isomerism in the Heterobimetallic 1:1 Adducts of Copper(I) Halides With Tris(dithiocarbamato)cobalt(III)
Authors: Engelhardt LM , Healy PC , Skelton BW , White AH
Published: September 2010

Reaction of copper(I) iodide with tris (N,N- dipropyl -and N, N- diisopropyl-dithiocarbamato )cobalt(III), [Co(S2CNR2)3 ≡ Co( dtc )3](R = Pr or Pri ), yields 1:1 adducts which have been characterized by single-crystal X-ray structure determination. Crystals of the propyl species are monoclinic, P21/c, a 13.722(7), b 16.854(7), c 16.787(8)Ǻ, β 121.66(3)°, R was 0.056 for No 2834 'observed' reflections. The isopropyl derivative is orthorhombic, Ccca , a 33.93 (1), b 13.616(8), c 14.574(5)Ǻ; R was 0.075 for No 726. Each adduct is dimeric [Co( dtc )3](CuI2Cu)[Co( dtc )3]; the propyl derivative has crystallographically imposed i symmetry, whereas the isopropyl adduct has quasi-222 symmetry. Thus, the chiralities of the pair of Co( dtc )3 moieties in the dipropyl adduct are opposite, whereas in the isopropyl adduct they are the same.
Organoamidometallics. II. Decarboxylation Syntheses and Structures of [N,N-Dimethyl-N'-(Polyfluorophenyl)Ethane-1,2-Diaminato(1-)]Platinum(II) Complexes
Authors: Buxton DP , Deacon GB , Gatehouse BM , Grayson IL , Black DS
Published: September 2010

The complexes Pt[N(p-HC6F4)CH2CH2NMe2]X(L) (L = py , X = Cl or Br; L = 2- methylpyridine or 4-methylpyridine, X = Cl ) have been prepared by decarboxylation reactions between PtX2( dmen ) ( dmen = N,N- dimethylethane - 1,2-diamine) and thallous pentafluorobenzoate in the appropriate hot pyridine. Other organoamidoplatinum (II) complexes, Pt[N(R)CH2CH2NMe2] X( py ) (R = p-HC6F4, X = I; R = C6F5, X = Cl , Br or I; R = p-MeC6F4, X = Cl ; R = p-ClC6F4 or p-BrC6F4, X = I) and Pt[N(R)CH2CH2NMe2] Cl ( dmpy ) (R = p-HC6F4; dmpy = 2,5-dimethylpyridine), have been prepared by analogous decarboxylations between PtX2( dmen ), thallous 2,3,5,6- tetrafluorobenzoate, and the corresponding polyfluorobenzene, RF. The mixed halogen complex Pt[N(C6F5)CH2CH2NMe2]I0.63Cl0.37( py ) has been prepared similarly and the crystal structure determined. This shows square-planar stereochemistry with the halogen and pyridine trans to NC6F5 and NMe2 respectively. Comparison of spectroscopic data suggests the other complexes have similar stereochemistry.
New Isothiocyanate Sesquiterpenes From the Australian Marine Sponge Acanthella pulcherrima
Authors: Capon RJ , Macleod JK
Published: September 2010

Two new sesquiterpene isothiocyanates (1) and (3), together with the known sesquiterpene isothiocyanates (2) and (4) and the sesquiterpene isonitrile (5), have been identified as the antimicrobial components of Acanthella pulcherrima. The isothiocyanate (1) is enantiomeric to epipolasin-A (6), and thus provides the first reported occurrence of an enantiomorphic pair among the group of marine natural products characterized as sesquiterpene isothiocyanates.
Monoacetals Derived From 12-α-Hydroxyandrosta-1,4-diene-3,17-dione and Androsta-1,4-diene-3,12,17-trione
Authors: Collins DJ , Krause NE
Published: September 2010

Conversion of 12α-hydroxyandrosta-1,4-diene-3,17-dione (5) into the corresponding 17-cyclic ethylene acetal (1) was accompanied by acid- catalysed attack of ethylene glycol at C3 to give 17,17-ethylenedioxy- 3-(2′-hydroxyethoxy)-1-methylestra-1,3,5(10)-trien-12a-ol (2), which was the major product with prolonged reaction times. Exchange dioxolanation of androsta-1,4-diene-3,12,17-trione (8), prepared by Jones oxidation of (5), gave selectively the 12-monoacetal (9): the regioisomeric 17-monoacetal (4) was obtained by oxidation of the hydroxy acetal (1) with chromium trioxide in pyridine. The trione (8) likewise afforded selectively the 12,12-ethylenedithio acetal (11). Treatment of the trione (8) with p- toluenesulfonic acid in refluxing benzene gave 1-hydroxy-4-methylestra-1,3,5(10)-triene-12,17- dione (7a).
Steric Influences on the Ground State of Iron(II) in the Tris(3,3'-dimethyl-2,2'-bipyridine)Iron(II) Ion
Authors: Craig DC , Goodwin HA , Onggo D
Published: September 2010

The tris ( ligand ) complex ions of iron(II) and nickel(II) with 3,3′-dimethyl-2,2′-bipyridine (L) are described. Salts of [FeL3]2+ display anomalously temperature-dependent magnetic and spectroscopic properties which arise from a temperature-induced singlet (1A1) ↔ quintet (5T2) spin transition. The structures of [ML3][ClO4]2(M = Fe, Ni) have been determined and these reveal a strong twist (c. 37°) of the pyridine rings about the C-C bridge. This forces the metal atoms out of the bonding planes of the donor nitrogen atoms and effectively reduces the interaction between L and the metal atoms. The average M-N distances are 2.064 Ǻ (M = Fe) and 2.102 Ǻ (M = Ni). Crystal data: the two complex salts are isostructural in monoclinic space group C2/c. [FeL3][ClO4]2: a 12.252(8), b 15.568(5), c 19.288(11) Ǻ, β 93.62(3)°; Z 4; [NiL3][ClO4]2: a 12.255(5), b 15.619(4), c 19.419(9) Ǻ, β 93.23(2); Z 4.
Chemistry of the Podocarpaceae. LXXII. Ring-C Modifications of Totarol
Authors: Cambie RC , Clark GR , Rickard CEF , Rutledge PS , Ryan GR , Woodgate PD
Published: September 2010

Totarol (1) has been converted into conjugated dienolides which have the B/C-ring systems found in naturally occurring nagilactones A and C and their analogues. Thus, treatment of the epoxide (11) with titanium(IV) tetrachloride affords the desired 7,9(11)- diene (12) and the saturated γ- lactone (23). Treatment of the epoxide (11) with diazabicyclo [3.4.0]non-5-ene gives a high yield of the butenolide (24); the alcohol (25) has been shown to be an intermediate in this reaction. Treatment of (11) with lithium iodide dihydrate in collidine gives the butenolides (24) and (26), and the novel rearrangement product (27) which is slowly converted on standing into the epoxide (29). Treatment of (11) with anhydrous lithium iodide gives the α- pyrone (30). The structures of compounds (11), (23), (24) and (29) have been determined by single-crystal X-ray diffraction measurements.
Clemmensen Reduction. IX. Structure and Reactions of a Cyclopropane-1,2-diol
Authors: Clark GR , Davis BR , Hinds MG , Rickard CEF
Published: September 2010

The β-keto aldehyde , 1-methyl-2-oxocyclododecanecarbaldehyde (4), was converted into a mixture of two cyclopropane-1,2-diyl diacetates , 12- methyl- cis-bicyclo [10.1.0]tridecane-cis-1,13-diyl diacetate (6) and 12- methyl-trans- bicyclo [10.1.0]tridecane-trans-1,13-diyl diacetate (8). The structure of (6) was established by means of a single-crystal X-ray study. The crystals are monoclinic, space group P21/c, with four molecules in a unit cell of dimensions a 12.326(1), b 14.998(2), c 10.388(3) Ǻ, β 108.33(1)°. The structure was solved by direct methods, and refined to an R factor of 0.059. Protonolysis of the corresponding diols leads to compounds not normally encountered in such systems but the genesis of the major products can be rationalized.
Exciton Spectra of the 9-Aminoacridine Chromophore
Authors: Fornasiero D , Kurucsev T
Published: September 2010

From the concentration dependence of the spectrum of 9-aminoacridine hydrochloride in neutral aqueous solution we determined the spectrum of the dimeric dye species. Two further 'dimeric' spectra' of the 9- aminoacridine chromophore have been obtained as the low- and high-temperature forms of N,N′- di (acridin-9-yl)hexane-1,6-diamine in aqueous solution. We interpreted the dimer spectra in the region between about 245 and 275 nm in terms of vibronic exciton theory and discussed the implications of the results to the structure of the dimers . Application of vibronic exciton theory to the visible region of the dimer spectra has resulted in at most qualitatively acceptable fits only, due to the breakdown in this region of the spectra of the single dominant vibrational mode approximation.
The Collision-Induced Dissociations of Deprotonated Amines in the Gas Phase
Authors: Raftery MJ , Bowie JH
Published: September 2010

The major collision-induced fragmentations of deprotonated primary and secondary amines are best rationalized as proceeding through the intermediacy of ion complexes. For example, the characteristic fragmentation of deprotonated ethylamine isMeCH2NH- → [Me-(CH2=NH)] → CH2N- + CH4 Secondary alkylamines behave in a similar fashion. The occurrence of proton transfer as a prelude to fragmentation is rare: the only example observed in this study is the probable reaction PhNEt →→ PhNHCHMe →
[(PhNH=CH)Me-] → C7H6N- + CH4 which is preceded or accompanied by proton transfer between the methylene and phenyl substituents. Deprotonated aniline undergoes specific elimination of CNH from the 1-position to form the cyclopentadienyl anion. Finally, retro reactions are observed for
the piperazine anion, e.g. HN(CH2CH2)2N
→ -CH2CH2N=CH2+CH2NH
Structure and Conformations of GABA-Transaminase Inhibitors. V. 4-[(2-Hydroxy-3,6-dimethylbenzyl)-methylamino]butanoic Acid Monohydrate
Authors: Andrews PR , Gulbis JM , Iskander MN , Mackay MF , Dipaola C
Published: September 2010

As part of a program to define conformational detail of potential inhibitors based on the calculated transition state of GABA-T, we report the crystal structure of the title compound. Crystals were triclinic and belong to the space group Pī with a 10.110(1), b 9.358(1), c 13.933Ǻ, α 90.37(1), β 93.27(1), γ 88.12(1)? and Z 4. Refinement on 3505 data measured with Cu Kα radiation converged at R 0.052. The two independent inhibitor molecules are essentially identical in conformation detail and are in a dipolar form. There is no intramolecular hydrogen bonding between the GABA nitrogen and phenolic oxygen but extensive intermolecular hydrogen bonding links the molecules into a three-dimensional network in the crystal.
Scrambling of the Label in [13C2] Biphenylene Obtained on Pyrolysis of [1,6,13C2] and [2,3,13C2]-2-(3',3'-Dimethyltriazenyl)\benzoic Acid
Authors: Brown RFC , Coulston KJ , Eastwood FW , Vogel C
Published: September 2010

Flash vacuum pyrolysis of 2-(3′,3′-dimethyltriazenyl)benzoic acid (6) above 350? gives biphenylene and N,N- dimethylaniline. The acid (6) was synthesized with 13C2 labels placed as in (13) to generate [1,6- 13C2] benzyne. F.v.p . of labelled acid (13) from 400-850° gave biphenylene samples which showed 13C spectra consistent with an increasing extent of carbon rearrangement from [1,6-13C2] benzyne to [1,3-13C2] benzyne with increasing temperature. This is in accord with direct rearrangement of benzyne (Scheme 1) but it is probable that more than one mechanism is operating. The labelling evidence suggests that N,N- dimethylaniline is formed by re-addition of dimethylamine to benzyne.
Synthesis and Biological Evaluation of a Series of Substituted 4,5-Diphenylpyridine-2,6(1H,5H)-diones
Authors: Andrews PR , Brinkworth RI , Partridge AC , Reiss JA
Published: September 2010

We report the synthesis of a series of disubstituted 4,5- diphenylpyridine-2,6(1H,5H)- diones (8),(10),(12)-(21), their characterization by 1H and 13C n.m.r . spectroscopy and their receptor binding affinities for catecholamine and benzodiazepine receptors.
Synthesis and Properties of Coronands Incorporating Lariat Sulfide and Sulfoxide Groups
Authors: Raguse B , Ridley DD
Published: September 2010

A series of 8-substituted 19-methoxy-17-methyl-3,6,10,13- tetraoxabicyclo[13.3.1]nonodeca-1(19),15,17-trienes has been prepared and their complexations with alkali metal and ammonium cations studied. When the 8-substituent contained sulfide functionality weak complexes formed, but hosts with lariat sulfoxide substituents formed complexes- with greatest specificity for lithium ions.
Crystal-Structures of 2 3-Substituted 10,11-Dimethoxy-1,2,3,4,5,6-Hexahydro-7,9-etheno-3-benzazecine Derivatives
Authors: Jia XY , Bremner JB , Skelton BW , White AH , Winzenberg KN
Published: September 2010

The title compounds are 3-aza[6](1,7)-naphthalenophanes with 3-Me and 3-CO2Me substituents, C18H23NO2 and C19H23NO4; in the former the chemical shift of the naphthalene hydrogen enclosed by the medium nitrogen-containing ring is the highest yet observed in a derivative of this type ( σ 9.33). In order to examine the environment of this hydrogen atom and the expected associated naphthalene ring distortions in both compounds, single-crystal X-ray structure
determinations have been carried out at 295 K showing the transannular H…N distance in the methyl derivative to be remarkably short at 2.08(2) � . Crystals are triclinic, P1, a 11.683(3), b 10.846(3), c 6.729(2) �, α 90.08(2), β 93.33(2), γ 112.88 Z 2; R was 0.041 for 1378 'observed' reflections. Crystals of the 3-CO2Me derivative are also triclinic, P1, a 12.587(9), b 10.650(4), c 6.758(3) � , a 91.91(3), β 100.51(4), γ 104.74(5)° Z 2; R 0.067 for 1267 'observed' reflections.
Untenospongin A and B, Novel Furanoterpenes With Coronary Vasodilating Activity From the Okinawan Marine Sponge Hippospongia sp
Authors: Umeyama A , Shoji N , Arihara S , Ohizumi Y , Kobayashi J
Published: September 2010

New furanoterpenes, untenospongins A and B, have been isolated from the Okinawan marine sponge Hippospongia sp. as potent coronary vasodilating agents, and their structures elucidated to be (E,E)-1,11-bis(furan-3-yl)-4,8-dimethylundeca-7,10-diene-4,6-diol (1) and (E,E,E)- l,ll -bis(furan-3-yl)-4,8-dimethylundeca-l,4,8-trien-6-ol (2) on the basis of spectral data.
Kinetic v. Thermodynamic Effects During a Wolff-Kishner Reduction
Authors: Brecknell DJ , Carman RM , Schumann RC
Published: September 2010

A Wolff-Kishner reduction is discussed which leads to kinetic products through reduction of hydrazones derived from thermodynamically less-stable ketones of an equilibrium mixture. The syntheses and conformational analyses of a range of 9-substituted 2,3,6,7-tetramethyldecahydroanthracenes are discussed.
Synthesis and Characterization of Pendant Arm Encapsulated Complexes of Cobalt(III)
Authors: Achilleos AA , Gahan LR , Nicolaidis KA
Published: September 2010

The synthesis and characterization of an octahedral cobalt(III) complex of the octaamine ligand 5,5-bis(4-amino-2-azabutyl)-3,7-diazanonane-1,9-diamine, [co( asen )]3+, is described. Two approaches to the preparation of encapsulated derivatives of [Co(asen)]3+ are also described. The first approach involves reaction of [Co(asen)]3+ with nitromethane and formaldehyde in the presence of base. After extensive chromatographic purification [(1-(4-amine-2-azabutyl)-8-nitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane )cobalt(III)]5+ was isolated. The second more convenient method employs precautionary protection of the pendant primary amine of [Co( asen )]3+, as the benzenesulfonate, prior to reaction with the same capping reagents. Both approaches result in an encapsulated complex bearing a pendant 4-amine-2-azabutyl moiety. The protecting group is stable under reaction conditions required for successive chemical modifications of the capping nitro group to amine, chloro and proton capped cages, but is readily removed in refluxing acidic solution.