Showing papers in "Australian Journal of Chemistry in 1970"

Complexes of binucleating ligands. III. Novel complexes of a macrocyclic binucleating ligand

Abstract: By reaction of 5-methylisophthalaldehyde with 1,3-diaminopropane in the presence of various metal salts the following complexes have been isolated: MCu2Cl2,6H2O, MCu2(ClO4)2,2H2O, MCu2(HSO4)2,H2O, MNi2Cl2,2H2O, MCo2Cl2,2CH3OH, MFezCl2,2CH3OH, MMn2Cl2,2H2O, MZn2Cl2,2H2O, (MH2)Ni(ClO4)2,2H2O where MH2 represents the macrocyclic tetrakis-Schiff base obtained by condensation of two molecules each of the diamine and dialdehyde components and M represents the derived dianion which behaves as a novel macrocyclic binucleating ligand. On the basis of magnetic and spectral evidence the complexes are assigned binuclear structures in which the cations are in an approximately square-pyramidal environment. These structural features have been confirmed in the case of MCu2Cl2,6H2O by an independently conducted X-ray crystallographic analysis. It is suggested that (MH2)Ni(ClO4)2,H2O is closely related to the others in that the nickel environment is square-pyramidal and that essentially the same organic ligand framework is present, with two protons rather than a metal ion occupying the second cavity of M.

Derivatives of 1,10-Phenanthroline-5,6-quinone

Abstract: 1,l0-Phenanthroline-5,6-quinone is prepared from 1,l0-phenanthroline via 5-nitro-1,l0-phenanthroline and 5-amino-1,l0-phenanthroline. It is converted by standard methods into 4,5-diazafluoren-9-one, 4,5-diazafluoren-9-ol,4,5-diazafluorene, and the new heterocyclic system dipyrido[3,2-a:2',3'-clphenazine. These four compounds each form a complex with cupric chloride. They thus represent a new series of chelating agents. By reaction with ethylene dibromide, dipyrido[3,2-a:2',3'-c]-phenaiine forms a diquaternary salt which is reduced in aqueous solution by a one-electron transfer to a highly coloured radical cation. Polarography experiments show that the reduction potential of the salt is -0.40 V against a standard calomel electrode.

Complexes of binucleating ligands. II. Geometrical models for potential nitrogen fixing systems

Abstract: The synthesis and some properties of a series of complexes, LCu2(X), are discussed where L is the binucleating trianion derived from d-methylisophthal-aldehyde di-2'-hydroxyanil [2-hydroxy-5-methyl-1,3-xylene-?,?'-diylidenebis(2-hydroxyphenylamine)] and X- is OH-, OR- ; pyrazolate anion; binuclear structures are assigned to these compounds on the basis of spectral and magnetic evidence. In the compound formulated as (L,H2O)Cu2(OCH3) it is suggested that the water molecule is added across one Schiff base link in L. The possible relevance of the results to a long-term project concerned with the synthesis of potential nitrogen-fixing systems is briefly discussed.

Oxidation of carbohydrates with chromium trioxide in acetic acid. I. Glycosides.

Abstract: Fully acetylated methyl β-D-hexopyranosides are oxidized by chromium trioxide in acetic acid to acetylated methyl 5-hexulosonates. Catalytic hydrogenation of these keto esters leads into the L-series. The corresponding a-D-glycosides are not oxidized in the same way, with the exception of methyl tetra-O-acetyl-α-D-idopyranoside. Both α- and β-anomers of the acetylated fnranosides are oxidized to aoetylated methyl 4-hexulosonates. The octaacetates of α- and β-lactose are similarly oxidized, the ring of the galactose moiety being opened. The methyl pyranoside of a branched-chain sugar, with no hydrogen atom on C5, is oxidized to a 4-keto ester, acetyl migration occurring from O4 to O5.

Oxidation of hydrazones with iodine in the presence of base

Abstract: The oxidation of 14 hydrazones with iodine in the presence of base (generally triethylamine) was investigated. The typical reaction products are mixtures of gem-diiodides and vinyl iodides obtained in total yields of 38-85%. The features of the reaction are consistent with a mechanism involving an intermediate iododiazonium salt and/or an iodocarbonium ion. The preparation and purification of hydrazones was investigated.

Dihydropyrrolizines. III. Preparation and reactions of derivatives related to pyrrolizidine alkaloids

Abstract: 1,2-Dehydropyrrolizidine derivatives, mainly the hepatotoxic alkaloids and their amino alcohols, are converted into 6,7-dihydro-5H-pyrrolizine derivatives. The dehydro derivatives of the amino alcohols are prepared with chloranil. Oxidation by manganese dioxide or potassium permanganate, or catalytic dehydrogenation, also leads to the desired dihydropyrrolizines together with products at a higher oxidation level such as 7-oxo and 1-formyl derivatives. The dehydro derivatives of the ester alkaloids are best prepared by the action of acetic anhydride on the N-oxides. The reactions of the dihydropyrrolizines with alcohols and amines, and their N.M.R. spectra, are discussed.

A synthesis of acronycine

Abstract: Improved syntheses of certain O-and N-methyl derivatives of 1,3-dihydroxy-acridone are described. Thermal rearrangement of the appropriate 3-α,α-dimethyl-propargyl ethers in the series yields products which may be methylated to acronycine.

Cyclic phosphines and arsines. II. Cyclic arsines

Abstract: The constitutions of the cyclopolyarsines (AsR)n (R = methyl, ethyl, n-propyl, and phenyl) have been investigated by nuclear magnetic resonance and mass spectrometric techniques. A systematic study of their fragmentation under electron impact at different ionization potentials has confirmed the presence of pentameric alkyl and hexameric phenyl cyclic arsines. Variable temperature N.M.R. spectra obtained for pentamethylcyclopentaarsine have been interpreted in terms of a rapid pseudorotation process. Some mixed methylphenyl cyclic arsines have been identified.

Crystalline cobalt, zinc, manganese, and iron alkoxides of glycerol

Abstract: A series of crystalline metal glycerolato complexes has been prepared. The preparation of the cobalt, zinc, manganese, and iron complexes [(1 )-(4)] was achieved by heating (above 110o) glycerol with metal acetates, carbonates, oxalates, oxides, or hydroxides. The structure of (1) has been determined by X-rays and contains Co-O-Co-O and Co-O-C-C-O rings. X-ray powder diffraction and i.r. data are given for (1)-(4). These show (1) and (2) to be isostructural and that (3) and (4) are variants of these. The insolubility of (I), (2), (3), and (4) is in accord with their polymeric nature.

Solvent effects on the ultraviolet absorption spectra of o-, m-, and p-Hydroxybenzylideneimines

Abstract: The ultraviolet absorption spectra of the mono-salicylideneimines of ethylamine, ethanolamine, and n-butylamine and of the bis-salicylideneimines of ethylenediamine, trimethylenediamine, and 1,3-diaminopropan-2-ol have been separately examined in various solvents: water, absolute ethanol, dioxan, and cyclohexane. A comparison of these spectra with those of the N-methylimines of m- and p-hydroxy-benzaldehydes in similar solvents indicates that the o- and p-hydroxybenzylideneimines exist mainly as the dipolar keto amines in very polar, hydrogen-bonding solvents whereas the m-isomers exist mainly as the enol imine tautomeric form in all solvents.

The chemical constituents of Australian Zanthoxylum species. V. The constituents of Z. pluviatile Hartley; the structures of two new lignans

Abstract: The bark of Zanthoxylum pluviatile Hartley yielded xanthyletin, hesperidin, (-)-or-oanadine methiodide, protopine, lupeol, savinin, sesamin, sucrose, and two new lignans, pluviatilol and pluviatolide. The leaves gave rutaecarpine, kokusaginine, β-sitosterol, an alkane mixture, and pluviatolide. From the wood there were isolated hesperidin, skimmianine, and β-sitosterol; in addition, evidence for the presence of ohelerythrine was obtained. Structures (3) and (7) are proposed for pluviatolide and pluviatilol respectively from chemical and spectroscopic considerations. From an aged phenolic fraction from the bark the new substance, pluviatide (ll), was isolated and its structure determined; it was probably an artefact derived from pluviatilol.

Synthesis of (E,Z)-α-,(Z,Z)-α-, and (Z)-β-farnesene

Abstract: The three farnesenes (E,Z)-or-, (Z,Z)-or-, and (2)-P- were synthesized from (cis) (2)-nerolidol by dehydration with phosphoryl chloride in pyridine. The i.r., u.v., N.M.R., and mass spectra of the six possible α- and β-farnesenes are compared as well as their behaviour on g.1.c. on several liquid phases. The α-farnesene which predominates in apples was confirmed as being (E,E)-α-farnesene and the minor isomer, previously thought to be (E,Z)-α-farnesene, was shown to be (Z,E)-α- farnesene.

Some rheological and electrokinetic properties of kaolinite suspensions

Abstract: The rheological behaviour of kaolinite sols has been studied as a function of pH and in the presence of adsorbates. The Bingham yield value shows a pronounced maximum at about neutral pH due, it is suggested, to the presence of extended chains of particles attached together by electrostatic interactions between edges and faces, as has been suggested by Street. At high pH values the particles behave as individuals and the yield value can be very effectively correlated with the attractive and repulsive forces between them, using the basic notions of colloid stability theory. Adsorption of long-chain quaternary ammonium compounds on the clay surface at high pH enabled the particle interaction energy to be altered over a wide range and this adsorption itself allowed a study of the van der Waals interaction energy between the CH2 groups of the adsorbate; a value of 1.2kT was found for this latter energy, in excellent agreement with estimates based on micellization in solution.

Natural pungent compounds. III. The paradols and associated compounds.

Abstract: A new series of pungent compounds, the 1-(4'-hydroxy-3'-methoxyphenyl). alkan-3-ones, has been isolated from grains of paradise (Amomum melegueta Roscoe) and detected in ginger (Zingiber officinale Roscoe). The name, paradol, which has been previously applied to a mixture of these compounds and the gingerols, is suggested as a group name prefixed with a number corresponding to that given to the gingerol with the same side-chain length to distinguish individual members. The structure of [6]-paradol, as suggested by spectroscopic techniques, was confirmed by synthesis from [6]-gingerol. It occurred in grains of paradise in quantities up to 1.5% and was accompanied by (+)-[6]- gingerol in almost equal amounts. Trace quantities of [8]-gingerol, [a]-paradol, and [6]-shogaol were also present.

Transition metal complexes of substituted alkynes. V. Compounds derived from Tri- and Tetra-cobalt carbonyl complexes

Abstract: Treatment of dodecacarbonyltetracobalt with several fluorocarbon alkynes has given complexes of stoicheiometry Co4(CO)10,(alkyne). For comparison, analogous complexes of the related hydrocarbon alkynes have also been prepared. Infrared, nuclear magnetic resonance, and mass spectra of the complexes are given and the probable structure of the complexes deduced. The reaction of both fluorocarbon and hydrocarbon alkynes with the cluster carbonyl compounds Co3(CO)9CY (Y = CH3, C6H5, CO2CH3) has also been investigated. The products obtained in these reactions include substituted benzenes and the two organocobalt complexes Co2(CO)6(alkyne) and Co2(CO)4(alkyne)3. The probable mode of formation of these compounds is discussed. The role played by the various complex types in the reactions of alkynes with cobalt carbonyls is also considered.

Synthesis of phenanthroindolizidines. II. The synthesis of (±)-tylocrebrine, (±)-tylophorine, (±)-antofine, and (±)-2,3-dimethoxyphenanthroindolizidine

Abstract: A new synthesis of the racemic forms of the phenanthroindolizidine alkaloids, tylocrebine, tylophorine, and antofine, together with the previously unknown 2,3-dimethoxyphenanthroindolizidine, is described. Some features of the n.m.r. spectra of the final products and certain of the synthetic intermediates are discussed.

Crystal field spectra of d3,7 ions. VI. The weak field formalism and covalency

Abstract: When the problem of an ion in a crystal field is solved using the unperturbed atomic wave functions as basis functions, the free ion energies appear explicitly in the diagonal terms of the secular determinant where they can be adjusted as experimental parameters. By fitting the observed crystal field energy levels in this scheme, a set of modified free ion energy levels can be derived for Dq = 0, and it is found that in most cases a single set of electrostatic repulsion parameters F2 and F4 describes the energies, provided a Trees correction is applied. The values of F2 and F4 obtained in this way from crystal spectra of Cr3+ in ruby, yttrium gallium garnet, other oxides, and K3Cr(CN)6 and of Co2+ in ZnAl2O4 are reduced by covalency from their free ion values. The reduction for P2 is greater than for F4 because of its greater sensitivity to the outer part of the radial distribution function, where covalency plays its major part. It is concluded that the differential expansion of the t2 and e orbitals in the crystal field is not great, and that nephelauxetic effects in crystal field spectra should more properly be related to the F2 and F4 parameters of Condon and Shortley through the weak field formalism, rather than to Racah's B parameter in the strong field approach. The latter results in unsound conclusions about the effects of covalency. Analysis of the spectra of CrBrs and C0C14" suggests that the d electrons are not adequately described by two electrostatic repulsion parameters and the usual crystal field theory should be applied cautiously.

Metabolites of some Alternaria species. The structures of altenusin and dehydroaltenusin

Abstract: Fungal metabolites from some Alternaria spp. are described. Structures for altenusin and dehydroaltenusin are proposed.

Diterpenoids. XXIV. A survey of the Agathis species of North Queensland. Two new resin acids

Abstract: A phytochemical survey of the diterpenoid resin acids of the North Queensland species of Agathis is presented. The methyl esters [(9) and (14)] of two new resin acids are described.

Geminal interproton coupling constants in some methyl derivatives

Abstract: The geminal inter-proton coupling constants J(H-C-H) were obtained from the N.M.R. spectra of suitably deuterated compounds MenX where X = C, Ge, Sn, Pb, 0, S, I, N, and Li. The relation between the magnitudes of J(H-C-H), J(13C-H), and electronegativity of X in this series is explored and some correlations are proposed. The data for methyllithium do not fit with the remainder of the results. It is tentatively concluded that in this series of compounds J(H-C-H) is a periodic property.

Hemi-alkoxides from reactions of trimethylaluminium with aldehydes or ketones

Abstract: One mole of an aldehyde or ketone reacts stoicheiometrically with one mole of trimethylaluminium dimer at ambient temperature in hydrocarbon solvents to form a "hemi-alkoxide" in which an alkoxy group and a methyl group bridge two aluminium atoms. Benzaldehyde, acetone, acetophenone, benzophenone, and cyclohexanone give p-alkoxy-p-methyl-tetramethyldialuminiums (Me2A1.OR.Me.AlMe2; R = CHPhMe, But, CphMea2 CPh2Me, and 1-methylcyclohexyl, respectively). Such compounds can also be prepared in low yields starting from alcohols, rather than aldehydes or ketones. The analogous compound, NezAl.N=CPhMe.Me.AlMez, is formed by reaction of benzonitrile with one mole of trimethylaluminium dimer in the absence of solvent at 100o. Exchange of methyl groups between bridge and terminal sites in these new compounds has been studied by proton magnetic resonance spectroscopy.

A proton magnetic resonance and preparative study of trimethylenediamine complexes of cobalt(III)

Abstract: The preparation of trans-[Co(tn)2Cl2]Cl,3.5H2O and [Co(tn)3]Cl3,H2O (1,3-diaminopropane = tn) is shown to proceed more readily and with greater yields when methanol solvent is employed instead of water. The preparation of the new species [Co(tn)2PO4]4H2O, [Co(tn)2(ox)]Cl,H2O, trans-[Co(tn)2(OH)H2O]-(ClO4)2,2H2O, and trans-[Co(tn)2(NH3)2]AsO4,3H2O is reported together with a modified preparation of [Co(tn)2CO3]ClO4. These preparations are discussed in terms of reaction mechanism. The p.m.r, spectra of the above species, trans-[Co(tn)2(NO2)2]NO2, cis-[Co(tn)2(H2O)HPO4]+, and cis-[Co(tn)2(H2O)2]3+ are reported in a range of solvents. The nature of the solvent markedly influences the observed chemical shifts and fine structure. The spectra are interpreted in terms of varying rates of conformational interchange of the tn ligands, and variation of solvent-solute interactions.

Polarization energies of molecular crystals

Abstract: The electrostatic polarization energies have been calculated for 17 molecular crystals, including some of two-components. Comparison with photoelectric emission data confirms that the energies of ionized states in organic crystals can be described in terms of properties of the free molecule and classical electrostatic interaction energies. The calculations were made in more detail and for a greater number of compounds than has been attempted previously; contributions from terms formerly neglected are significant especially for large molecules like pentacene.

Circular dichroism spectra of amino acid complexes. III.* Copper(II) compounds

Abstract: The solution circular dichroism spectra of the 1: 1 and 1: 2 copper(II) complexes of a series of α-amino acids are reported for the region 12500-25000 cm-1. These spectra and spectra of the isolated 1: 2 complexes dispersed in KBr disks have been interpreted as arising from three Cotton effects with a -,+,- sign pattern for the L configuration, except for the L-proline spectra, which were analysed in terms of a +,-,+ pattern. A tentative assignment is made for these Cotton effects, and the relative contributions of vicinal and conformational effects to the rotational strength are discussed.

Diterpenoids: XXV. Dundathic acid and polycommunic acid

Abstract: Dundathic acid is a polymer consisting principally of units (4) derived from communic acid. Experiments designed to show the major structural features are described.

Preparation of 1,3-thiazines: Sulphur analogues of nucleic acid pyrimidine bases

Abstract: Sulphur analogues of uracil and thymine have been prepased, in which the N1 atom of the pyrimidine base has been replaced by a sulphur atom. A number of general synthetic methods are described for the synthesis of these 1,3-thiazines. The uracil analogues were prepared from the related 2-thio-1,3-thiazines, by acid hydrolysis of the 2-alkylthio derivative. 3,4-Dihydro-4-oxo-2-thio-2H-1,3-thiazine, its N-methyl and N-ethyl derivatives were obtained by cyclization of the addition compound resulting from the reaction of propiolic acid and the appropriate dithiocarbamic acid. The generality of this reaction, when propiolic acid is replaced with other acetylenic acids or their related esters, is discussed. The crystalline addition compounds obtained from dithiocarbamic acid and either propiolic acid or methyl propiolate were all shown by p.m.r, spectroscopy to have cis stereo-chemistry. The thymine analogues were prepared by an alternative route, which utilized the intramolecular cyclization of S-ethyl-N-(β-methoxymethacryloyl)dithiocarbamate to form 2-ethylthio-6-methyl-4-oxo-4H-1,3-thiazine, followed by acid hydrolysis of the 2-ethylthio group. Related intramolecular cyclization reactions of N-acyl-dithiocarbamates formed the 5-acetyl-, the 5-cyano-6-methyl-, the 5-cyano-6-ethyl-, and the 6-methyl-2-ethylthio-1,3-thiazine derivatives. A third approach involved the successful acid catalysed ring-opening-ring- closure of a. 4-oxo-2-thio-1,3-oxazine to the isomeric 2,4-dioxo-1,3-thiazine.

Two modes of chelation in Bis(4-iminopentane-2,3-dione 3-oximato)nickel(II)

Abstract: The red, neutral, diamagnetic nickel complex formed by the reaction of bis(pentane-2,4-dionato)nickel(II) with nitrite and ammonium ions has been investigated by p.m.r., infrared, and mass spectrometry. It is proposed that this complex has a novel unsymmetrical structure in which the ligand [CH3COC(NO)C(NH)CH3]- exhibits two different modes of chelation in the same molecule. The modes differ in that an oximino nitrogen-to-nickel bond in one chelate ring is replaced by an oximino oxygen-to-nickel bond in the other. 2H-, 15N-, and 18O-labelled derivatives of the complex have been prepared and the isotopic shifts observed in the infrared spectra have been used to assign particular vibrational modes. An analogous unsymmetrical structure is also proposed for bis(1-ethoxyoarbonyl-2-iminopropan-1-one oximato)nickel(II).