bluuebunny/crossref_metadata_2025 huggingface dataset:
The Preparation of Methyl 7-Iodohept-5-Ynoate and Related Electrophiles
Authors: Haynes RK , Lambert DE , Parafiniuk KA , Schober PA , Turner SG
Published: September 2010

Methyl 7-hydroxyhept-5-ynoate, methyl 7-bromo- and 7-iodo-hept-5-ynoate, 7-hydroxyhept-5- ynenitrile, 7-bromohept-5-ynenitrile, 7-hydroxyhept-5-ynoic acid and 7-bromohept-5-ynoic acid have been prepared from 2-(prop-2-yny1oxy)tetrahydro-2 H-pyran and 1-bromo-3-chloropropane or 1-bromo-4-chlorobutane.
The Characterization of Some Iron Chromates
Authors: Mineely PJ , Scott DL
Published: September 2010

As the first step in a systematic review of a range of iron(III) chromates, the Mossbauer chemical shifts, quadrupole splittings and linewidths have been measured for a number of compounds. These parameters have been correlated with available structural information and the correlations have been applied to compounds with unknown structures and to the thermal decomposition products of the double chromates MFe (CrO4)2.nH2O with M = Na, K, Rb , Cs, NH4. Decomposition of the ammonium salt follows a different pathway, with the new mixed-valence compound, FeCr2O6, as an apparent intermediate.
Relative Stereoselectivity of the Reactions of (2R,3R)-Dibenzoyloxysuccinic and (2R,3S)-2,3-Dibenzoyloxysuccinic Anhydrides With Chiral Amines and Alcohols
Authors: Bell KH
Published: September 2010

Stereoselectivities of the reactions of (2R,3R)- and
(2R,3S)-2,3-dibenzoyloxysuccinic anhydrides with some chiral arnines and alcohols have been determined by 1H n.m.r. analysis of the mixture of diastereomers. In all cases the stereoselectivity was higher for the (2R,3R)-isomer and a simple model has been proposed to explain this. The structure of one of the diastereomers from the (2R,3S)-isomer has been confirmed by synthesis.
Heterocyclic Variants of the Purine System. I. Derivatives of Thiazolo[5,4-e]-1,2,4-Triazine
Authors: Jacobsen NW , Philippides AE
Published: September 2010

Derivatives of the thiazolo [5,4-e]-1,2,4-triazine ring system were prepared from appropriate 6-acylamino-1,2,4-triazin-5(2H)-ones by thiation and cyclization with phosphorus pentasulfide. 5-Methylthio-1,2,4-triazin-6-amines also gave thiazolo [5,4-e]-1,2,4-triazine derivatives when treated with carbon disulfide or phenyl isothiocyanate.
Qualitative Valence Bond Theory for Asymmetric Coordination in Tin(IV) Dithiolate Complexes
Authors: Harcourt RD , Tiekink ERT
Published: September 2010

Different modes of asymmetric coordination found for certain tin(IV) xanthate and dithiocarbamate complexes are rationalized in terms of valence-bond resonance schemes. As tin-atom lone-pairs are absent in these compounds, the observed asymmetry cannot be a consequence of lonepairlbond -pair repulsions.
The Treatment of Some Cyclic Thiocarbonates With Methyl Halide/Propylene Oxide
Authors: Patroni JJ , Stick RV
Published: September 2010

Treatment of thiocarbonates (OCSO) with methyl iodidelpropylene oxide at 80� can lead smoothly to the carbonate. In some cases, a competing process is the formation of iodo thiocarbonates ( OCOSMe ), and an explanation is provided for the product distributions observed. The corresponding reactions with methyl bromide and methyl chloride (as methyl chloroformate ) are much less efficient.
Organolanthanoids.X. Syntheses of Cyclopentadienyllanthanoids by Transmetalation Reactions in Pyridine, Acetonitrile and Ethers
Authors: Deacon GB , Forsyth CM , Newnham RH , Tuong TD
Published: September 2010

The complexes, (C5H5)3M( py ) (M = Nd, Sm, Eu or Yb ), (C5H5)2Eu( py ), and (C5H5)2Yb( py )2 have been prepared from the appropriate lanthanoid elements and thallous cyclopentadienide in pyridine, and (C5H5)3M( NCMe ) (M = Nd , Sm or Yb ) and (C5H5)2Yb( NCMe ) from similar reactions in acetonitrile. Ligand exchange or addition has also been used to give (C5H5)3Sm( py ), (C5H5)2Yb( py )2 and (C5H5)2Yb( NCMe ). Ytterbium metal reduces (C5H5)3Yb( py ) in pyridine to (C5H5)2Yb( py )2, which is oxidized back to (C5H5)3Yb( py ) by TI(C5H5). Europium with (C5H5)2Hg in tetrahydrofuran yields (C5H5)3Eu( thf ), and (C5H5)2Eu is not isolated by using an excess of metal. Oxidation of (C5H5)2Eu to (C5H5)3Eu is effected by (C5H5)2Hg in tetrahydrofuran but not by T1(C5H5) in 1,2-dimethoxyethane. Europium and ytterbium react with bis(pentafluoropheny1)mercury and cyclopentadiene in pyridine to give (C5H5)3M( py ) (M = Eu or Yb ).
Hydride Transfers During Friedel Crafts Reactions of 5,5-Dimethyl-4,5-dihydrofuran-2(3H)-one
Authors: Rae ID , Woolcock ML
Published: September 2010

5,5-Dimethyl-4,5-dihydrofuran-2(3H)-one (4,4-dimethylbutyrolactone) reacts with toluene and with p-xylene in the presence of anhydrous aluminium chloride to give 4-methylpentanoyl benzenes with one, two or three methyls on the benzene ring. Reduction of the side chain has taken place by hydride transfer from an aromatic methyl, the resulting benzylic carbocation going on to form diarylmethanes by reaction with solvent molecules.
Steric Effects. Internal-Rotation of 1-Aryl-8-Phenylnaphthalenes
Authors: Cosmo R , Sternhell S
Published: September 2010

A general, albeit low-yielding, synthesis of 1-aryl-8-phenylnaphthalenes was devised and used to prepare three l-(3'-X-5'-isopropylphenyl)-8-phenylnaphthalenes (X = H, F, Br). Activation parameters for the rotation of the 3'-X-5'4sopropylphenyl group were determined by dynamic m.m.r. spectroscopy.
Solution Properties of Tetraalkylammonium Halide and Alkali-Metal Halide Ion Pairs. The Relationship Between Dissociation Constants and Solubility Products
Authors: Mizerski W , Kalinowski MK
Published: September 2010

An empirical relation describing the effect of solvent on the dissociation constant ( Kd ) of ion pairs is described. An equation of the form pKd = apKso + bD-1 + c ( Kso and D stand for the solubility product of a given salt and for the electric permittivity of a solvent, respectively) has been tested with 13 sets of experimental data for salts containing tetraalkylammonium and alkali-metal cations. A successful correlation was obtained in 100% of the cases considered.
The Baker-Nathan Order: Hyperconjugation or a Solvent Effect?
Authors: Cooney BT , Happer DAR
Published: September 2010

The electronic effect of alkyl groups attached to an aromatic ring has been determined under varying conditions of electron demand by measuring their influence on the 13C n.rn.r. chemical shifts of the β-carbon of β-substituted styrenes. When the group, is para to the side chain their ability to donate electrons follows the order Me > Et > Pri > But, and, when meta, But > Pri > Et > Me. This order is the same in CCl4, CDCl3, Me2SO and EtOH solvent, the results suggesting that the Baker-Nathan effect is a hyperconjugative rather than solvation phenomenon.
Further Amathamide Alkaloids From the Bryozoan Amathia wilsoni
Authors: Blackman AJ , Green RD
Published: September 2010

Further investigations of the bryozoan Amathia wilsoni have yielded amathamides C-F, four new bromine-containing alkaloids, which are closely related in structure to the previously described amathamides A and B. There is no significant variation in the alkaloid content of different colonies of the bryozoan at the same location, but differences occur between samples of the bryozoan which have been obtained from different collection sites.
The Chemistry of Lauren-1-ene. VII. Further Rearrangements of Ring A Seco Derivatives
Authors: Hanton LR , Lorimer SD , Weavers RT
Published: September 2010

Treatment of the keto ester (2a) with acid can lead to either the conjugated diene (3) or the non-conjugated diene (4a). The structure of (4a) has been deduced from chemical and spectroscopic studies and by X-ray analysis of the derived iodo ketone (10d). This series of decalin derivatives exhibits a thermodynamically stable cis ring junction. The factors which control the production of dienes (3) and (4a) have been elaborated. A rearrangement which leads to a new lactone (16a) is also described.
15N Nuclear Magnetic Resonance Spectra of Phenylacetanilides
Authors: Yamagami C , Takao N , Takeuchi Y
Published: September 2010

15 N substituent chemical shifts (SCS) of a variety of anticonvulsant phenylacetanilides (1) and (2), with a substituent at the para or meta position of the aniline moiety, were analysed by means of DSP (dual substituent parameter) equations. For the sake of comparison, 15N scs of p-substituted anilines (3), and 13C chemical shifts of some ring carbons of (1) and (3) were also investigated. The similarity observed for the correlation of the carbon shifts para to the substituent for (1) and (3) indicates that the nitrogen shifts will be a better probe for the transmission of the substituent effect to nitrogen.
Photochemical and Photophysical Studies of Rose Bengal Poly(vinylpyrrolidone) — Application to the Photoreduction of Water
Authors: Ghiggino KP , Brown JM , Launikonis A , Mau AWH , Sasse WHF
Published: September 2010

The photophysics and photochemistry of the xanthen dye rose bengal have been studied both free in aqueous solution and when bound to poly( vinylpyrrolidone ) ( pvp ). Fluorescence, picosecond spectroscopy and laser flash photolysis measurements have been undertaken. The singlet and triplet excited state lifetimes of the dye are increased and the dye photostability is enhanced upon binding to the polymer. These observations may be explained on the basis of changes in the microenvironment surrounding the dye and restrictions on molecular diffusion in the polymer. The reduced rate of non- radiative decay and higher photostability of rose bengal in the presence of polymer leads to improved overall yields of hydrogen production during the photoreduction of water in reaction systems which incorporate the dye and pvp as a light-harvesting pigment. One of the most efficient systems for the photoreduction of water at pH 9 and above is reported.
Nitrones and Oxaziridines. XXXV. Synthesis of Cyclic Hydroxamic Acids From 2-Cyano-1-pyrroline 1-oxides
Authors: Black DS , Ooi KL
Published: September 2010

2-Cyano-1-pyrroline 1-oxides can be converted in high yield into the related cyclic hydroxamic acids by heating in aqueous hydrochloric acid. Eight examples are given.
Nitrones and Oxaziridines. XXXVI. Synthesis of Cyclic Thiohydroxamic Acids
Authors: Black DS , Ooi KL
Published: September 2010

2-Cyano-1-pyrroline 1-oxides (1) could not be converted directly into the related cyclic thiohydroxamic acids (8). Potassium ethyl xanthate transformed nitrones (1) into the imidates (2). The cyclic hydroxamic acids (4) can be converted into the thiohydroxamic acids (8) via the methoxypyrrolidinones (5) and the methoxypyrrolidine thiones (6), making use of sodium p- tolylmercaptide as the demethylating agent. Reaction of methoxy thiones (6) with trimethylsilyl iodide led to the formation of the 2-methylthio-1-pyrroline 1-oxides (7).
A New Series of Sesquiterpenoids From a Gorgonian
Authors: Cambie RC , Craw PA , Buckleton JS , Clark GR , Rickard CEF
Published: September 2010

A new series of sesquiterpenoids containing a 2,2,7-trimethyl-4-(1-methylethyl )indan skeleton have been isolated from an unnamed Primnoeides sp., a gorgonian found in coastal New Zealand waters. The structures of these sesquiterpenoids have been formulated on the basis of spectral and chemical evidence, together with an X-ray structure determination of one of the new compounds.
Studies in the Cycloproparene Series: The Behavior of Alkylidenecycloproparenes Towards Nucleophiles and Oxidizing Agents
Authors: Buckland SJ , Halton B , Stang PJ
Published: September 2010

The alkylidenecycloproparene (1) reacts with potassium t- butoxide to give the ring-expanded heptafulvene (3). Epoxidation of (1) provides the hydroxy ketone (5) probably via the spiro epoxide (4) but carbene additions fail to give spirocycle (7). Photooxygenation of (1a,b) gives products (5),(12)-(14) and (16) which are explicable in terms of initial formation of dioxetan (10); products (13) and (14) result from 1H-cyclopropa[b] naphthalenone (11). By comparison (1c) provides phenanthraquinone acetal (17) in low yield. With osmium tetroxide and sodium periodate , (1a) gives benzophenone (12a) in competition with hydroxy ketone (5a) and 2,2-diphenylcyclobutanaphthalenone (20). The modes of formation of the various products are discussed.
Metal-Complexes of 1,10-Phenanthroline Derivatives. XV. Complexes of 2-(3,5-Dimethylpyrazol-1-yl)-1,10-phenanthroline
Authors: Abushamleh AS , Goodwin HA
Published: September 2010

Iron(II) and nickel(II) bis ( ligand ) complexes of 2-(3,5-dimethylpyrazol-1-yl)-1,10-phenanthroline (L) have been prepared. The field strength of L as determined from spectral data for the nickel complex is in the range encompassing the critical value at the singlet (1A1) ↔ quintet (5T2) crossover for iron(II). The magnetic properties of the iron(II) complex both in solution and in the solid state are anomalous, and indicative of the occurrence of a thermally induced spin transition. Mossbauer spectral data confirm this, and reveal separate contributions from the singlet and quintet species with a strong temperature-dependence of their relative intensities. Magnetic data for the complex in solution are consistent with a simple high spin ↔ low spin equilibrium, and lead to values of ΔH = 23�0.5 kJ mol-1 and ΔS = 66�5 J K-1 mol-1 for the low spin → high spin transformation.
Cation-Binding Properties of Macrocyclic Polyether and Polythioether Diesters and Dithioesters From 1,10-Phenanthrolines and 1,8-Naphthyridines
Authors: Chandler CJ , Deady LW , Reiss JA
Published: September 2010

The cation-binding properties of the title compounds (1)-(7) with the alkali, alkaline-earth, silver, ammonium and copper(II) picrates have been determined from host/guest complexation experiments. The association constants depend on the ligand cavity diameter, the nature of the heterocycle , the type and number of donor atoms and charge on the complexed cation. Dynamic 1H n.m.r . spectroscopy has also been employed, to demonstrate the comparable stability of a 21-membered 1,10-phenanthrolino ligand to its pyridine analogue in binding a benzylammonium salt. From this study, information on both the complex and ligand conformations was obtained.
Investigation of a New Xanthate Ligand. The Crystal and Molecular Structures of Nickel and Cadmium (Methoxyethyl)xanthates
Authors: Abrahams BF , Hoskins BF , Tiekink ERT , Winter G
Published: September 2010

The crystal structures of Ni(S2COCH2CH2OCH3)2 and Cd (S2COCH2CH2OCH3)2 have been determined. Crystals Ni(S2COCH2CH2OCH3)2 are orthorhombic, Pbca , with a 7.852(1), b 7.126(2), c 24.963(4)Ǻ, Z 4. Crystals of Cd (S2COCH2CH2OCH3)2 are monoclinic, P21/c, with a 12.712(2), b 4.215(1), c 13.400(2)Ǻ, β 104.60(1)°, Z 2. In both structures the central metal atom is coordinated by the sulfur atoms in a planar arrangement, an unexpected observation for the cadmium compound.
The Stereochemistry of Organometallic Compounds. XXXII. Hydrocyanation of Derivatives of Amino Alkynes
Authors: Jackson WR , Perlmutter P , Smallridge AJ
Published: September 2010

The hydrocyanation of a range of amino alkyne derivatives has been studied by using nickel-based catalyst systems. The phthalimido derivatives have been shown to give good yields of unsaturated cyano amine derivatives, and some of these have been converted into both saturated and unsaturated amino acids.
The Synthesis of Oxo-Bridged CrIII-O-VV Compounds
Authors: Elliott RL , West BO
Published: September 2010

CrIVO ( tpp = dianion of 5,10,15,20-tetraphenylporphyrin) can undergo redox reactions with VIVO(L)2 [L = anions of quinolin-8-ol (Q) or pentane-2,4-dione ( acac )] to yield oxo -bridged complexes (tpp) CrIIIOVV (L)2. The presence of CrIII and VV ions is supported by magnetic and e.s.r . measurements.
Reactions of (10-Methyl-10-nitro-1,4,8,12-tetraaza-cyclopentadecane)copper(II) Ion in Aqueous Hydrochloric Acid, Including Zinc Reduction. Crystal-Structure of (2-methyl-1,4,8,11-tetraaza-cyclotetradec-1-ene)copper(II) Perchlorate
Authors: Lawrance GA , Oleary MA , Skelton BW , Woon FH , White AH
Published: September 2010

The zinc/aqueous hydrochloric acid reduction of (10-methyl-10-nitro-1,4,8,12-tetraaza-cyclopentadecane)copper(II) ion, [Cu{(3)}]2+, yields the hydrochloride salts of the expected 10-methyl-1,4,8,12-tetraazacyclopentadecan-10-amine (5) and also 14-amino-4,8,11-triazatetradecan-2-one (4) in approximately 2:1 ratio. Reaction of (10-methyl-10-nitro-1,4,8,12-tetraazacyclopentadecane)copper(II) ion in aqueous hydrochloric acid alone leads to bond scission and hydrolysis adjacent to the nitro-substituted carbon of the macrocycle to form 15- nitro-2,6,9,13-tetraazahexadecan-1-ol (7), which may be reduced in zinc/acid to the 15-amino-2,6,9,13-tetraazahexadecan-1-ol molecule (8). The acid hydrolysis reaction is not simply reversed by addition of base. The ring-opened species (7) is apparently an intermediate in formation of (4) from (3), via a metal- catalysed Nef reaction which converts the CH(NO2)CH3 arm into CO(CH3). Reaction of (7) with Cu2+ at pH 9.5 slowly forms (2-methyl-1,4,8,11-tetraazacyclotetradec-1-ene )copper(II), [Cu{(6)}]2+, via formation of (4) and an intramolecular condensation around the metal ion. This complex was characterized by an X-ray crystal structure analysis of the perchlorate salt.
The Chemistry of Laurenene. IX. Crystal-Structure of a Ring A Seco Keto Acid
Authors: Hayman AR , Simpson J , Weavers RT
Published: September 2010

X-Ray crystallography has shown that the laurenene derived keto acid, 1-oxo-1,2-secolaurenan-2-oic acid (2a), exists in two distinct twist conformations in the crystal lattice. Comparison with data previously reported for a derivative of the 15-epimer (1b) provides an explanation for the extraordinary difference in reactivity between ring A seco laurenane derivatives with the 15α- and 15β-methyl
stereochemistries.
Compounds of 3,4,7,9,9,14,16-Octamethyl- (and 7,9,9,14,14,16-Hexamethyl-3,4-diphenyl) 1,2,5,6,10,13-Hexaazacyclohexadeca-2,4,6,16-tetraene With Nickel(II) and Copper(II). Preparations and Kinetics of Acid Hydrolysis Reaction
Authors: Curtis NF
Published: September 2010

The complex nickel(II) cation of the bis-diazine macrocycle 3,4,7,9,9,14,14,16-octamethyl-1,2,5,6,10,13-hexaazacyclohexadeca-2,4,6,16-tetraene, omht, is formed by reaction of the complex of 3,3,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone with butane-2,3-dione, and the complex of the 7,9,9,14,14,16-hexamethyl-3,4-diphenyl homologue, bzht, is similarly prepared by reaction with 1,2- diphenylethane-1,2-dione. The cation [Cu(hmtd)]2+ is formed by metal ion substitution for a precursor of the nickel(II) cation. Compounds of the nickel(II) cations occur as singlet ground state perchlorate salts, or as triplet ground state octahedral compounds with additional ligands, e.g. [Ni(omht)(NCS)2], [{Ni(omht)(N3)}2](ClO4)2 and [Ni(omht)(en)] (ClO4)2. The singlet ground state [Ni(omht)]2+ cation in dimethyl sulfoxide converts into a triplet ground state species with first-order rate constant of 2.1(2)×10-6 s-1 at 25°C, 5.1(2)×10-5 s-1 at 50°C. The cations are slowly hydrolysed by acid, and pseudo-first-order rate constants in 2 mol l-1 HCl/NaCl for hydrolysis of [Ni(omht)]2+ and [Cu(omht)]2+ at 25° and 50°C are reported. These are of the order of 10-5 (25°C), 10-4(50°C) s-1, with a non-linear dependence on [H+], and with the reactions faster for the nickel(II) cation.
Synthesis of Bridgehead Halides by Barton Halodecarboxylation
Authors: Della EW , Tsanaktsidis J
Published: September 2010

Bridgehead carboxylic acids can be converted into their corresponding chlorides very efficiently under Barton halodecarboxylation conditions. Addition of the acid chloride to a suspension of the sodium salt of 1-hydroxypyridine-2(1H)- thione in boiling carbon tetrachloride under irradiation leads to excellent yields of the bridgehead chloride via the derived thiohydroxamic ester. In a useful modification for the synthesis of volatile halides, either 1,1,1-trichloro-2,2,2-trifluoroethane or trichlorofluoromethane can be employed as substitute solvents. It is found that the Barton procedure is applicable to the synthesis of labile bromides such as 1-bromobicyclo[3.1.1]heptane for which the usual Hunsdiecker reaction fails. For these, and other brominations , 2-bromo-2-chloro-1,1,1-trifluoroethane ('Halothane') is shown to function as an efficient solvent/bromine atom donor.
Lewis-Base Adducts of Main Group 1 Metal Compounds. X. Lithium Bromide and Iodide Complexes With Acetonitrile (1 : 2, 1 : 4 Respectively)
Authors: Raston CL , Whitaker CR , White AH
Published: September 2010

Although only sparingly soluble in acetonitrile, lithium(1) bromide and iodide crystallize as acetonitrile adducts, structurally characterized as LiX/MeCN 1 : 2 and 1 : 4 respectively by single-crystal structure determinations. The bromide is a �,�′-dibromo-bridged dimer , ( MeCN )2LiBr2Li( NCMe )2)] (monoclinic, P21/n, a 7.624(2), b 12.61 2(2), c 8.047(3) � , β 98.94(3)°p; Z 2 dimers; R 0.038 for No 1081 'observed' reflections); Li-Br, N 2.534(7), 2.492(8); 2.031(9), 2.047(8) � respectively, with Li…Li, 3.17(1); Br…Br, 3.8989(9) � respectively. The iodide is ionic, [Li( NCMe )4]+1- (orthorhombic, P21221, a 20.66(1), b 12.208(6), c 8.4296) �, Z 6; R 0.062 for No 866).
4-(6'-Methoxy-3',4'-dihydronaphthalen-1'-yl)butan-2-one and the Derived Guareschi Imide
Authors: Collins DJ , James AM
Published: September 2010

4-(6′-Methoxy-3′,4′-dihydronaphthalen-1′-yl)butan-2-one (6b) was condensed with ethyl cyano-acetate to give a mixture of the geometric isomers of the α, β unsaturated cyano ester (8), reaction of which with the anion derived from cyanoacetamide gave the Guareschi imide (7). Attempts to hydrolyse this to 3-[2′-(6″-methoxy-3″,4″-dihydronaphthalen-1″-yl)ethyl]-3-methylglutaric acid (4) gave only polymeric material. The preparations of 2,2-ethylenedioxy-4-(6′-methoxynaphthalen-1′-yl)butane (5a) and the corresponding butanone (5b) are also described.
Preparation of 2-(3-Bromo-1-methylpropyl)-1,3-dioxolan and the Corresponding Chloride From 2-Methylbutyrolactone
Authors: Collins DJ , James AM
Published: September 2010

Lithium aluminium hydride reduction of ethyl 4-chloro-2-methylbutanoate (4a), derived from 3-methyldihydrofuran-2(3H)-one (2-methylbutyrolactone) (1), gave 4-chloro-2-methylbutan-1-ol (5a), oxidation of which with pyridinium chlorochromate afforded 4-chloro-2-methylbutanal (8a). The aldehyde (8a) was converted into 2-(3?-chloro-1′-methylpropyl)-1,3-dioxolan (7a) in 47% overall yield from (1). 2-(3′-Bromo-1′-methyIpropyl)-1,3-dioxolan (7b) was similarly obtained in 49% overall yield from (1). Attempted conversion of 3-methyltetrahydrofuran-2-ol (2) into the corresponding cyclic ethylene acetal gave epimeric mixtures of 2-(3′-methyltetrahydrofuran-2′-yloxy)ethanol (6) and 2,2′-ethylenedioxybis(3-methyltetrahydrofuran) (9).
Benzotriazole Photostabilizers: Nitration of Tinuvin P
Authors: Amiet RG
Published: September 2010

Nitration of the commercial photostabilizer Tinuvin P, 2-(21-hydroxy-5′-methylphenyl)- 2H-benzotriazole,* has been shown to yield 2-(2′-hydroxy-5′-methyl-3′-nitrophenol)-2H-benzotriazole. The anion of this nitro compound is intensely coloured and may be the cause of yellowing of polymers in which Tinuvin P has been incorporated.
A Cycloadduct of Diphenylpropadienylidene Meldrums Acid With Diphenylpropadienylidenetriphenylphosphorane
Authors: Brown RFC , Eastwood FW , Fallon GD , Lavecchia L , Schank K
Published: September 2010

An attempt to obtain diphenylpropadienylidene Meldrum's acid (5) by a Wittig reaction between oxo Meldrum's acid (6) and the phosphorane (2) gave, in low yield, a cycloadduct of (2) and (5). Its structure (7) was determined by X-ray crystallography.
15N Labeling Studies of the Reactions of 4-t-Butyl-2,6-dimethyl-4-nitrocyclohexa-2,5-dienone and 2,4-Di-t-butyl-6-methyl-4-nitrocyclohexa-2,5-dienone With Nitrogen-Dioxide; the Mechanism of Formation of 2,5,6-Trinitrocyclohex-3-enones
Authors: Blunt JW , Hartshorn MP , Jensen RG , Waller AG , Wright GJ
Published: September 2010

Reaction of the 15N-labelled 4-nitro dienone (15b) with nitrogen dioxide in benzene gives the 2,5,6-trinitrocyclohex-3-enones (19), (20), (22) and (24) with retention of some 15N-label at C6. Similar reaction of 15N-labelled 4-nitro dienone (18b) gives the 2,5,6-trinitrocyclohex-3-enones (30), (31), (34) and (38), and the 2-hydroxy-5,6- dinitrocyclohex-3-enones (33) and (37) all with retention of some 15N-label at C6. These results are rationalized in terms of 2,5-addition of nitrogen dioxide to corresponding intermediate 6-nitro dienones (27) and (40).
The Nitration of 4-Methylphenol, 3,4-Dimethylphenol and 3,4,5-Trimethylphenol With Nitrogen Dioxide
Authors: Hartshorn MP , Judd MC , Vannoort RW , Wright GJ
Published: September 2010

Reaction of 4-methylphenol (la) with excess nitrogen dioxide in either benzene or dichloromethane gives the 4-nitro dienone (2a) and the 2,6-dinitrophenol (5). Similar reactions of 3,4-dimethylphenol (Ib) yields the 4-nitro dienone (2b), the 2,6-dinitrophenol (8) and the 4-hydroxy 2,6-dinitro dienone (9), while reaction of 3,4,5-trimethylphenol (1c) gives the 4-nitro dienone (2c), the 2,4-dinitro dienone (11) and the 2,4,6-trinitro dienone (12a). The reaction pathways by which these products are formed are described and the results of reactions of postulated intermediates with nitrogen dioxide presented.
Two Novel Bisalkylated Norscalaranes From the Sponge Carteriospongia foliascens
Authors: Quinn RJ , Tucker DJ
Published: September 2010

Two novel 20,24-dimethyl-25-norscalaranes have been isolated from the hexane extract of Carteriospongia foliascens and their structures determined by a combination of 1H and 13C n.m.r. spectroscopy and e.i . mass spectrometry.
β-Carboline-3-carboxylic Acid (9H-Pyrido[3,4-b]indole-3-carboxylic Acid) and Related Compounds
Authors: Maclaren JA
Published: September 2010

The synthesis of β-carboline-3-carboxylic acid and its esters (4) by oxidation of the corresponding 1,2,3,4-tetrahydro derivatives (2) or of the 3,4-dihydro derivatives (3) has been studied. A novel synthesis of the esters (3) [and hence of (4)] has been achieved in high yield by cyclization and elimination from the enamine (5). The relative inhibition of binding of a benzodiazepine to rat brain membranes by the esters (2)-(4) has been determined.
5-Methoxyphenanthrene-4-carboxylic Acid
Authors: Gillis RG , Porter QN
Published: September 2010

Lead tetraacetate oxidation of phenanthrene-4,5-dicarboxylic acid in acetonitrile with pyridine affords 5-hydroxyphenanthrene-4-carboxylic acid as its lactone , which can be methylated as the sodium salt, giving 5-methoxyphenanthrene-4-carboxylic acid, albeit in poor yield. New spectroscopic evidence (particularly 13C n.m.r.) confirms that 5-formylphenanthrene-4-carboxylic acid, which is an intermediate in the synthesis, exists as the lactol , 4-hydroxyphenanthro[4,5-cdeloxepin-G(4H)-one.
Imidazo[1,2-b]Pyridazines. V. Syntheses and Central Nervous Activities of Some 3-Alkoxy-6-benzylthio(substituted benzylthio and Other phenylalkylthio)-2-phenyl(and substituted phenyl)imidazo[1,2-b]pyridazines
Authors: Barlin GB , Davies LP , Ireland SJ , Ngu MML
Published: September 2010

Syntheses are reported for a number of 3-alkoxy-6-benzylthio(substituted benzylthio and other phenylalkylthio )-2-phenyl(and substituted phenyl)imidazo[l,2-b]pyridazines. These compounds were then examined for their ability to displace 3H-diazepam from rat brain membranes. In preliminary tests, in the presence of 100 �m γ- aminobutyric acid (GABA) and under standard assay conditions (see Experimental), 6-benzylthio-3-methoxy-2-phenylimidazo[l,2- b]pyridazine gave an lC50 value of 25nM (IC50 for unlabelled diazepam is 4.3 nM ); its 6-(m- aminophenyl ), 6-(p- aminophenyl ) and 6-(m- nitrophenyl ) analogues gave values of 15, 9 and 8 nM respectively.
A Classical Trajectory Calculation of Average Energy Transfer Parameters for the CH3OO+Ar System
Authors: Whyte AR , Gilbert RG
Published: September 2010

A newly developed method is used to calculate the average energy transferred in collisions between a highly vibrationally excited methylperoxy radical and argon bath gas. The method involves modelling the process through classical trajectory simulations with accurate intra- and inter-molecular potentials. These calculations show that the root-mean-squared internal energy transferred per collision is c. 275 cm-1 for 300 ≤ T/K ≤ 600 (the CH302 internal energy being 104 cm-1, the dissociation threshold), while the same quantity for rotational energy is c. 290 cm-l. These results make it possible for rate data obtained by other workers for the reaction CH3O2+M ↔ CH3+02+M over limited pressure and temperature ranges to be used to predict reliably the appropriate rate coefficients at any temperature and pressure.
Reactions of 6-Benzyl-2-t-butyl-4,6-dimethyl-cyclohexa-2,4-dienone and 6-Benzyl-4-t-butyl-2,6-dimethylcyclohexa-2,4-dienone With Nitrogen Dioxide
Authors: Hartshorn MP , Robinson WT , Waller AG , Wright GJ
Published: September 2010

Reaction of the 2-t-butyl-4-methylcyclohexa-2,4-dienone (7) with nitrogen dioxide in benzene gives the four 4,5-dinitrocyclohex-2-enones (9)-(12), the three 2,5-dinitrocyclohex-3-enones (13)-(15), and the 2-hydroxy-5-nitrocyclohex-3-enone (17). Under the same reaction conditions the 4-t-butyl-2-methylcyclohexa-2,4-dienone (8) gives the four 2,5-dinitrocyclohex-3-enones (19)-(22), and the three 2-hydroxy-5-nitrocyclohex-3-enones (23)-(25). X-Ray structure determinations are reported for compounds (9), (10), (13), (14), (19) and (25). In solution at 40 the dinitro ketone (20) rearranges to give dinitro ketone (19) and 2-hydroxy-5-nitro ketones (23) and (24). The reaction mechanisms for the various reactions are discussed.
Pyrolysis of Methane to Higher Hydrocarbons: A Thermodynamic Study
Authors: Larkins FP , Khan AZ
Published: September 2010

Some basic thermodynamic parameters such as Gibbs free energies, enthalpies of reactions and equilibrium compositions of products from the pyrolysis and partial oxidation of methane to higher hydrocarbons in the gas phase have been determined within a consistent framework for the temperature range 800-1500 K and the pressure range 0.1-3 MPa , by using the CSIRO-SGTE THERMODATA system. It has been established that the pyrolysis of methane to higher hydrocarbons, e.g. acetylene, ethylene, ethane, prop-1-ene, propane, benzene, toluene, naphthalene, 1-methylnaphthalene and 2-methylnaphthalene, considered as separate reactions, is a highly endothermic reaction with the Gibbs free energies for the individual reactions being positive until 1300 K. The aromatics are thermodynamically most favoured with the equilibrium yields increasing with temperature. Addition of O2 lowers the heats of synthesis and the free energies for methane conversion but no enhancement in the equilibrium yields of hydrocarbons is observed. When solid carbon is allowed, it is the dominant product in all cases with the equilibrium yields for all hydrocarbons becoming negligible. Increasing the pressure at a particular temperature has more effect on the lowering of the equilibrium conversion of methane than on the suppression of solid carbon. Such data are valuable for understanding the conversion limits for methane into higher hydrocarbons.
Molecular Topology of Linked Anthracenes: X-Ray Structure Analyses of Alkyl Di-9-anthryl-glycolates, 9-Anthryl 9-Anthrylmethyl Ethers and Their Photoisomers
Authors: Becker HD , Skelton BW , White AH
Published: September 2010

The molecular structures of ethyl di-9-anthrylglycolate (1) and methyl di-9-anthrylglycolate (2), as well as those of three isomerization products of (2), have been established by single-crystal X-ray diffraction studies. In both (1) and (2), the anthracenemoieties are characterized by marked deviations from planarity. The stereospecific course of the thermal and photochemical isomerization of (2) by Diels -Alder reaction is suggested to be governed by the spatial demand of the alkoxycarbonyl group. Base-catalysed isomerization of (2) by migration of 9-anthryl from carbon to oxygen is associated with steric relief.
Synthesis of Some Naphthothiadiazolophanes. Derivatives of 4,10,14-Ethenylylidene-7H-[1,2,3]thiadiazolo[5,4-e]azacyclotridecine and 4,11,15-Ethenylylidene[1,2,3]thiadiazolo[5,4-f]azacyclotetradecine
Authors: Bremner JB , Jaturonrusmee W
Published: September 2010

Reaction of 7,8-dimethoxy-1,2,4,5,1lb, 11c-hexahydrobenzo [de]pyrrolo[3,2,1-ij][1,2,3]thiadiazolo[4,5-g]quinoline (3a) and 8,9-dimethoxy-2,3,5,6,12b,12c-hexahydro-1H-[1,2,3]thiadiazolo-[5',4':3,4]naphtho[2,1,8-ijalquinoline (3b) with cyanogen bromide in the presence of potassium carbonate gave the naphthothiadiazolophanes 12,13-dimethoxy-5,6,8,9-tetrahydro-4,10,14- ethenylylidene-7H-[1,2,3]thiadiazolo[5,4-e]azacyclotridecine-7-carbonitrile (4a) and 13,14-di-methoxy-6,7,9,10-tetrahydro-4,11,15-ethenylylidene[1,2,3]thiadiazolo[5,4-f]azacyclotetradecine-8(5H)-carbonltrile (4b) in 39 and 89% yield respectively;7-(2-bromoethyl)-1,2-dimethoxy-5,6,6a,7-tetrahydro-4H-benzo[de][1,2,3]thiadiazolo[4,5-g]quinoline-6-car bonitrile (5a) was also obtained in 40% yield from the former reaction. Products of analogous structure resulted from (3a,b) when methyl chloroformate was used In place of cyanogen bromide. Attempted Diels-Alder reactions of (4b,c) with some powerful dienophiles were unsuccessful.
The Nitration of p-Cymene With Nitrogen Dioxide in Acetic Anhydride
Authors: Hartshorn MP , Robinson WT , Waller AG , Wright GJ
Published: September 2010

Reaction of p-cymene (1) with nitrogen dioxide in acetic anhydride gives polynitro nitrates (4)-(10), polynitro acetates (11)-(13), and nitro aromatic compounds (14)-(17). X-Ray crystal analyses are reported for compounds (5)-(9), (11) and (12).
Synthetic Hydrophilic Porphyrins. Preparations and Spectra of Alkoxycarbonylmethyl and Carboxymethyl Pyridinium Porphyrins
Authors: Arnold DP
Published: September 2010

The preparation and spectroscopic properties of a quaternary pyridinium porphyrin containing ethoxycarbonylmethyl groups are described. Partial saponification of the ester groups yields a series of mixed ester/carboxylate salts which show evidence of strong intermolecular association in aqueous solution. The fully saponified tetracarboxylate inner salt was prepared in high yield and has properties which conflict with a previous report.
5-Hydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one (Tectochrysin) and 2,5-Dihydroxy-7-methoxy-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one: Isolation From Uvaria rufas and X-Ray Structures
Authors: Chantrapromma K , Pakawatchai C , Skelton BW , White AH , Worapatamasri S
Published: September 2010

5-Hydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one ( tectochrysin ) (1), 5-hydroxy-7,8-di-methoxy-2-phenyl-4H-1-benzopyran-4-one (7-0-methylwogonin) (2), 5-hydroxy-6,7-dimethoxy-2-phenyl-4H-1-benzopyran-4-one (6,7-O,O-dimethylbacaiein) (3) and 2,5-dihydroxy-7-methoxy-2-phenyl-4H-1-benzopyran-4-one (4) have been isolated from the roots of Uvaria rufas Blume. The crystal structures of (1) and (4) have been determined by X-ray diffraction methods from diffractometer data at 295 K and refined by full matrix least squares. Crystals of (1) are monoclinic P21/c, a 10.l28(3), b 15.289(5), c 8.215(4) �,β 92.39(3)� Z 4; R 0.045 for No 874 'observed' reflections; crystals of (4) are monoclinic P21/c, a 12.299(4), b 6.489(3), c 16.579(6) �, β 90.24(3)� Z 4; R 0.051 for No 1016.
The Chemistry of Laurenene. X. A New Carbon Skeleton by Rearrangement of Laurenan-2-β-ol
Authors: Eaton PJ , Hayman AR , Weavers RT
Published: September 2010

Treatment of laurenan-2β-ol (2) with trifluoroacetic acid in dichloromethane at 0° gives as the major product the rearranged alkene (4). This compound has a new carbon-ring system containing three five-membered rings and one six- membered ring. The structure of (4) has been determined by a range of n.m.r. techniques applied to (4) and selected derivatives. Deuterium- labelling experiments have established that the rearrangement proceeds to a remote part of the molecule and then returns to its starting point.
New Chlorine-Containing Depsidones From Lichens
Authors: Elix JA , Jenkins GA , Venables DA
Published: September 2010

The depsidones, 3-O-demethylscensidin (2,7-dichloro-3-hydroxy-8-methoxy-1,6-dimethyl-11H-dibenzo[ b,e ][1,4]dioxepin-11-one)(5), O- methyldiploicin (2,4,7,9-tetrachloro-3,8-dimethoxy-1,6-dimethyl-11 H- dibenzo [ b,e ][1,4]dioxepin-11-one (6) and O- methylvicanicin (2,7-dichloro-3,8-dimethoxy-1,4,6,9-tetramethyl-11H-dibenzo[ b,e ][1,4]dioxepin-11-one) (13) have been detected in lichens for the first time and the structures of these metabolites have been established by comparison with synthetic material.
Pigments of Fungi. XV. An Efficient, Unambiguous Route to Unsymmetrically Substituted Dibenzyl Acyloins and Their Use in the Synthesis of Fungus Pigments of the Pulvinone and Grevillin Types
Authors: Gill M , Kiefel MJ , Lally DA , Ten A
Published: September 2010

Dibenzyl acyloins including those bearing unsymmetrically disposed aryl residues are assembled in high yield by reaction between the O-trimethylsilyl ethers of arylacetaldehyde cyanohydrins and benzyl Grignard reagents. These acyloins are deprotonated with lithium diisopropylamide to afford alcoholate-enolate dianions which can be made to react with carbonyldiimidazole and with oxalyldiimidazole, respectively, to ultimately afford fungus pigments of the pulvinone and grevillin types.
Stability Constants of Silver(I) Complexes of Bis(2-chloroethyl) Sulfide (Sulfur Mustard) and Some Related Thioethers in Polar Organic Solvents
Authors: Tilley RI
Published: September 2010

Stability constants of complexes formed between silver(I) and diethyl sulfide, 2-chloroethyl ethyl sulfide and bis (2-chloroethyl) sulfide (sulfur mustard) in acetone, methanol, dimethylformamide and dimethyl sulfoxide have been determined. The reduced stability of silver(I) complexes with ligands containing a 2-chloroethyl group has been explained in terms of the sulfonium ion character of the ligands.
A Revised Structure for Compound '2' and X-Ray Crystal Structure of Compound C, Components of Technical Chlordane
Authors: Smith TJ , Langdon AG , Wilkins AL , Wilcock RJ , Coddington JM
Published: September 2010

The structure of a component of technical chlordane hitherto considered to be a monochlorinated adduct of tetrachlorocyclopentadiene and cyclopentadiene is revised from (4) to that of 3a,4,5,5a,exo-6- pentachloro-1a,2,3,3a,5a,5b-hexahydro-1,3-methano-1H-cyclobuta [ cd ] pentalene (3c). The structure of a hexachlorinated analoguem known as compound C, and believed to be 3a,4,5,5a,5b,exo-6-hexachloro-1a,2,3,3a,5a,5b-hexahydro-1,3-methano-1H- cyclobuta [ cd ] pentalene (3a), has been confirmed by X-ray crystallographic analysis.
Candida cylindracea Lipase-Catalyzed Hydrolysis of Methyl Palmitate in Detergentless Microemulsion and Paraffin/Water Biphasic Media
Authors: Oconnor J , Aggett A , Williams DR , Stanley RA
Published: September 2010

The activity of lipase from Candida cylindracea has been investigated in the detergentless microemulsion media of n-hexane/propan-2-ol/water and in paraffin/water biphasic mixtures. Analysis of the product of hydrolysis, palmitic acid, was by a titrimetric method developed for non-specific assay of free fatty acids in these mixed-solvent media. The enzyme-catalysed hydrolysis of methyl palmitate was very slow in a complete non-aqueous system, but addition of small amounts of water led to an increased rate of reaction at atmospheric pressure and 37°C. The ability of the enzyme to work in these mixed-solvent systems under very favourable experimental conditions makes it particularly amenable to practical and cost-effective transformations.
Crystal-Structure of Bis(2,2'-6',2'-terpyridine)manganese(II) Bis(triiodide) [Mn(terpy)2](I3)2
Authors: Bhula R , Weatherburn DC
Published: September 2010

The crystal structure of [ Mn ( terpy )2](I3)2( terpy = 2,2°:6°,2°-terpyridene) has been determined by X-ray crystallography. The crystals are triclinic, space group Pī , a 9.357(4), b 8.600(2), c 24.531(8) Ǻ, α 93.64(2), B 95.58(3), γ 91.52(2)°, Z 2, V 1960(1)Ǻ3. The structure has been refined to a residual R of 0.065 (Rw 0.070). The coordination sphere of the metal ion is distorted octahedral with each terpy ligand coordinated in a meridional fashion. The structure is compared with those of other M( terpy )2n+ complexes formed by first-row transition metal ions.
Intramolecular Participation Reactions in Labda-8(17),14-dien-13-ol (Manool) Derivatives
Authors: Grant PK , Hanton LR , Tsai SF , Yap TM
Published: September 2010

Lewis acid treatment of a series of hydroxy epoxides promoted intramolecular nucleophilic epoxide opening to give hydroxy cyclic ethers. The regioselectivity of epoxide opening is controlled by a preference for SN2 attack at the more accessible epoxide carbon, provided this does not involve the formation of a strained ether ring. An intramolecular acetate transfer occurs in order to achieve the regioselective opening.
Cycloaddition Reactions of the Methano[10]annulene Derivative 9,9-Dichloro-1,4-dihydro-4a,8a-methanonaphthalene
Authors: Halton B , Russell SGG
Published: September 2010

9,9-Dichloro-1,4-dihydro-4a,8a-methanonaphthalene (4) adds the electron-deficient dienophiles 4-phenyl-1,2,4-triazoline-3,5-dione, maleic anhydride and dimethyl acetylenedicarboxylate to the α-face to give adducts (5)-(7) respectively; the addition of the alkyne requires Lewis acid catalysis. Inverse electron-demand addition of 3,6-diphenyl-1,2,4,5-tetrazine to the monoene component of (4) in hydrophilic solvent (ethane-1,2-diol) is thwarted; the CCl2 bridge is ejected and the 1,4-dihydronaphthalene formed is captured to give (ultimately) phthalazine (16). Dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate adds to (4) to give the methanobenzophthalazine (17b).
Thermal Dehydrochlorination of Poly(vinyl chloride) Model Compounds. I.
Authors: Boughdady NM , Chynoweth KR , Hewitt DG
Published: September 2010

The liquid phase (neat and solution) thermal degradation of a number of compounds which model the common defect groups found in pvc has been investigated. Compounds with halogen atoms at tertiary positions have stabilities similar to allylic halides. However, there was nearly a tenfold difference in the rate of reaction between the positionally isomeric 2-chloroalk-3-enes and 4-chloroalk-2-enes. Compounds with unsaturation within a longer chain or compounds lacking a terminal methyl group are somewhat less reactive. The dehydrochlorination reaction was confirmed to be accelerated by glass surfaces, hydrogen chloride and polar solvents.
Crystal Structure and Chirality of the Ansamycin Antibiotic Actamycin
Authors: Hambley TW , Parthasarathi V , Rickards RW , Robertson GB
Published: September 2010

The structure of the title
compound has been determined from diffractometer data recorded, initially, at 294 K and, subsequently, at 168 K. Crystals are triclinic, space group P1 with (168 K values in square brackets) a 16.080(2) [15.934(2)], b 15.958(2) [15.880(2)], c 8.443(2)Ǻ [8.233(1)Ǻ], α 85.55(1) [86.04(1)],β 82.65(1) [82.56(1)],γ 85.00(1)° [84.73(1)°], and contain two actamycin and two solvent ( tetrahydrofuran ) molecules in the asymmetric scattering unit. The structure was solved with DIRDIF and refined by block-diagonal least-squares analysis (of 168 K data) to R 0.049 ( wR 0.069) for 5640 reflections and 940 refined parameters. Molecules of actamycin (30-dechloro-2-demethyl-30-hydroxynaphthomycin A) exhibit the same relative stereochemistry (8S*,9S*,15S*,18S*,19S*,20S*) and double-bond configuration (2Z,4Z,6E,12E,16E,21E) as reported for crystalline 25-O-methylnaphthomycin A iminomethyl ether but are quite differently conformed. The two crystallographically inequivalent actamycin molecules in the present structure also exhibit substantial conformational (torsion angle) differences due, apparently, to the effects of intermolecular hydrogen bonding. Consideration of chiroptical data defines the absolute configuration of actamycin as 8S,9S,15S,18S,19S,20S and the helicity as P, as in naphthomycin A.
Micellar Catalysis of Organic Reactions. XXXI. A Study of the Effects of Micelles of Cetyltrimethylammonium Bromide on Some SNAr Reactions in Aqueous Binary Mixtures
Authors: Broxton TJ
Published: September 2010

The effect of micelles of cetyltrimethylammonium bromide ( ctab ) on the SNAr reactions of 1-fluoro-2,4-dinitrobenzene (1), 2-fluoro-5-nitrobenzoate (2) and 4-fluoro-3-nitrobenzoate (3) with sodium hydroxide in aqueous binary mixtures with several alcohols has been studied. Two products were detected in all of these reactions: the phenol from reaction with hydroxide ions, and an aryl alkyl ether from reaction with the alkoxide ions. Micelles of ctab increased the percentage yield of the ether product at the expense of the phenol for compounds (1) and (2) in most of the binary mixtures used. For compound (3), however, micelles of ctab had little effect on the product distribution. These differences were attributed to
differences in the orientation of substrates (2) and (3) when solubilized by micelles of ctab . Very high yields of the ether were obtained for the reaction of compound (1) with hydroxide ions in trifluoroethanol /water mixtures, and this was attributed to the considerable ionization of trifluoroethanol which was the most acidic alcohol used in this work. The lowest yield of the ether product was obtained in reactions of compound (1) with hydroxide ions in propan-2-ol/water mixtures since propan-2-ol was the least acidic alcohol used. These results are compared with those previously reported for the reaction of compound (1) in the presence of hydroxy-functionalized micelles and β- cyclodextrin. In the presence of micelles of ctab the aryl alkyl ethers derived from compounds (1) and (2) underwent a subsequent SNAr reaction with hydroxide ions during which the alkoxide ion was displaced. For compound (3) no subsequent reaction of the ether was detected in the presence of micelles of ctab . This was also attributed to the orientation of this product within the micelle. The reaction centre was buried in the micellar interior, and hence was shielded from a subsequent reaction. The rates of this subsequent reaction for compound (1), and of the decomposition of micellar aryl ethers and of cyclodextrin aryl ethers derived from compound (1), are also compared. The increase in the yield of the ether product in the presence of micelles was attributed to the increased ionization of alcohols in the presence of cationic micelles.
Reduction of Vicinal Dihalides. II. Leaving Group Effects on the Electrochemical Reduction of 1,2-Dihalo-1,2-diphenylethanes and 1,2-Dihalocyclohexanes
Authors: Fawell P , Avraamides J , Hefter G
Published: September 2010

Leaving group effects on the electrochemical dehalogenation of organic vicinal dihalides have been examined in acetonitrile for the 1,2-dihalo-1,2-diphenylethanes and trans-1,2-dihalo-cyclohexanes. Reduction potentials and product distributions support a stepwise addition of two electrons, as previously proposed for the isomers of 1,2-dibromo-1,2-diphenylethane. A general reduction mechanism for the vicinal dihalides is proposed. Literature data for the electrochemical reduction of the 5,6-dihalodecanes, previously thought to favour a concerted two-electron mechanism, may be explained in terms of a stepwise process.