Showing papers in "Australian Journal of Chemistry in 1953"
TL;DR: In this paper, a method of least squares is described for calculating activity coefficients from results of total vapour pressure measurements, and a method for computing activity coefficients is proposed for calculating the activity coefficient from the results of a single measurement.
Abstract: A method of least squares is described for calculating activity coefficients from results of total vapour pressure measurements.
606 citations
TL;DR: In this article, the head-to-tail linkage of the acetate units of a natural product containing orcinol or phloroglucinol nuclei was investigated.
Abstract: Correlations of the structures of some natural products containing orcinol or phloroglucinol nuclei, and related compounds, support the hypothesis that the molecules are elaborated, at least in part, by the head-to-tail linkage of acetate units. Chemical and biochemical evidence is cited in support of the hypothesis.
192 citations
TL;DR: In this paper, the ultraviolet spectra of benzene, toluene, and chlorobenzene at 2600 and 2000 Ǻ have been measured in carbon tetrachloride, chloroform, cyclohexane, 1%-hexane and ethanol.
Abstract: The ultraviolet spectra of benzene, toluene, and chlorobenzene at 2600 and 2000 Ǻ have been measured in carbon tetrachloride, chloroform, cyclohexane, 1%-hexane, ethanol, and water. Compared with the gases the solution spectra are all displaced to the red by amounts that agree qualitatively with the predicted effect of the solvent refractive index and the transition intensity according to the theory of Bayliss (1950). Quantitative agreement with this theory can be obtained only by assuming the effective cavity occupied by the solute molecule to be considerably smaller than the actual molecular size. The significance of this effect is discussed. The intensities of the solution spectra vary with the solvent refractive index, but in a way that is incompatible with the classical theory of Chako (1934). A marked increase in the intensity (particularly in toluene) is found where the solute absorption is close to an absorption band of the solvent, that is, for the 2600 Ǻ transitions in carbon tetrachloride and to a less extent in chloroform. In the 2600 Ǻ transition of benzene, a band appears in water, chloroform, and carbon tetrachloride that is very close to the position of the (0,0) band that is forbidden in the gas spectrum. The nature of this band is discussed.
63 citations
TL;DR: In this paper, the authors reported the absorption spectra of 43 substances believed to contain the -N=N- group and concluded that N=N stretching modes, if active in absorption, are contributors to either or both of the bands at the points mentioned.
Abstract: Infra-red absorption spectra, over the rock-salt region, are reported for 43 substances believed to contain the -N=N- group. In the " double bond " region two common frequencies are noted, at 1406 and 1579 cm-1 (with standard deviations of ±14 and ± 9 cm-1 respectively). Since these may arise wholly or partly from vibrations of the aromatic or heterocyclic nuclei adjacent to the azo-linkages, the conclusion is drawn that N=N stretching modes, if active in absorption, are contributors to either or both of the bands at the points mentioned.
48 citations
TL;DR: In this article, a general equation for the dielectric constant of a liquid is derived for a molecular model consisting, in the first instance, of an ellipsoid uniformly polarized in a principal direction, and in the second instance of an optically anisotropic ellipssoid ; in both cases the surroundings are assumed to form a continuum.
Abstract: Some earlier theories in which attempts have been made to allow for the influence of molecular shape on the static dielectric constant of a liquid are shown to be inaccurate. A general equation is derived for the dielectric constant of a liquid, and this is then applied to a molecular model consisting, in the first instance, of an ellipsoid uniformly polarized in a principal direction, and secondly, to an optically anisotropic ellipsoid ; in both cases the surroundings are assumed to form a continuum. The results of this more general approach applied to several substances are more satisfactory than those obtained by the original Onsager theory. The theory is also applied to mixtures, and in the special case of a dilute solution in a non-polar solvent, the equation of Ross and Sack is obtained when the ellipsoid is isotropic. A correlation has been noted in the discrepancies found when the dipole moment of a substance is calculated by means of observations on the pure liquid and on dilute solutions in a non-polar solvent, using the equations derived in the present paper.
38 citations
TL;DR: In this paper, the reversible reduction of nicotinamide methiodide and methochloride has been studied using cathodic reduction at a mercury surface, sodium dithionite, hydrogen and colloidal platinum, and various leuco-dyes.
Abstract: The reversible reduction of nicotinamide methiodide and methochloride has been studied using cathodic reduction at a mercury surface, sodium dithionite, hydrogen and colloidal platinum, and various leuco-dyes. The method of cathodic reduction was the most satisfactory. Polarography showed a 2-step reduction. Macro-reductions at a mercury surface suggested dimerization of the intermediate free radical. The behaviour of dihydromethylnicotinamide towards hydrogen ions, oxygen, iodine, potassium ferricyanide, ferric iron, and various dyes has been examined. Although it is not readily oxidized by oxygen it is capable of reducing most other systems with a higher Eo?:. Two methods of estimating the reduced compound are suggested and involve (a) the potentiometric titration of potassium ferricyanide at pH 9.1 and (b) the reduction and decolourization of 2.6-dichlorophenolindophenol at pH 4.7. The oxidation-reduction potential of nicotinamide methiodide has been measured by oxidative titration of the dihydro-compound at pH 9.1 and 30±0.01 °C and found to be -0.36 ± 0.02 V against the normal hydrogen electrode. The titration curve does riot show a separation of the two reduction steps. Evidence is discussed for the production of both o- and p-dihydromethylnicotinamide during reduction.
34 citations
TL;DR: In this paper, the theory presented in an earlier paper is developed as a method for the evaluation of' true dipole moments from data obtained from solutions in polar solvents and applied to values relating to solutions of several substances in chloroform, chlorobenzene, and nitrobenzene.
Abstract: The theory presented in an earlier paper is here developed as a method for the evaluation of' true dipole moments from data obtained from solutions in polar solvents. As illustrations, the new method is applied to values relating to solutions of several substances in chloroform, chlorobenzene, and nitrobenzene. The results, considering the nature of the problem, are satisfactory. The accuracy is greatest when the solute is highly polar and the dielectric constant of the solvent small. Aqueous solutions of pyridine and of two amino acids are also considered. In the latter cases especially, the predicted dipole moments agree most favourably with anticipated values obtained for the zwitterions by multiplying the electronic charge by the expected charge separation.
29 citations
TL;DR: The leaves of Acronychia baueri Schott as mentioned in this paper contain the acridine alkaloids melicopine, melicopsine, and melicopicine and the furoquinolines skimmianine, acronycidine, and kokusaginine, which have all been established previously.
Abstract: The leaves of Acronychia baueri Schott. contain the acridine alkaloids melicopine, melicopidine, and melicopicine and the furoquinolines skimmianine, acronycidine, and kokusaginine, the structures of which have all been established previously. In addition two new alkaloids are present. These are 2,4-dimethoxy-10-methylacridone (I) and a dimethoxydimethylpyranofuroquinoline which has been named acronidine. Acronidine has been degraded to a phenol which on methylation gives isokokusaginine (II). The alkaloid must therefore possess structure III or IV, the latter being preferred.
26 citations
TL;DR: In this paper, 1-hydroxy-3-methyl-6,8-dimethoxynaphthalene (VII) has been synthesized and shown to be identical with a phenol obtained from the degradation of eleutherinol dimethyl ether.
Abstract: 1-Hydroxy-3-methyl-6,8-dimethoxynaphthalene (VII) has been synthesized and shown to be identical with a phenol obtained from the degradation of eleutherinol dimethyl ether. This synthesis establishes the formula VI for eleutherinol, in agreement with prediction on biogenetic grounds.
24 citations
TL;DR: In this paper, a study of the thermal conductivities of a number of simple organic vapours at various pressures and temperatures was made and it was shown that the variation of conductivity with pressure is a function of gas imperfection.
Abstract: A study has been made of the thermal conductivities of a number of simple organic vapours at various pressures and temperatures. The measurements indicate that the variation of conductivity with pressure is a function of gas imperfection ; for substances with appreciable dipole interaction the effect is large, but for other substances where gas imperfection involves only van der Waals forces, the effect is much less. In all cases it is probable that the change in specific beat of the vapour with pressure is the main cause of the observed conductivity variation.
24 citations
TL;DR: The structures previously assigned to two constituents of Diospyros hebecarpa A. Cunn were confirmed by the synthesis of 5-hydroxy-7-methyl-l,4-naphthoquinone and its conversion to 1,4,5-trimethoxy-7methylnaphthalene as discussed by the authors.
Abstract: The structures previously assigned to two constituents of Diospyros hebecarpa A. Cunn. are confirmed by the synthesis of 5-hydroxy-7-methyl-l,4-naphthoquinone and its conversion to 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. By an independent route 5-methoxy-7-methyl-l,4-naphthoquinone has also been prepared, and has been converted to 1,4,5-trimethoxy-7-methylnaphthalene.
TL;DR: The known substances l-α-canadine methiodide, β-homochelidonine, chelerythrine, isocorydine methidide (a new alkaloid), lupeol, and hesperidin have been isolated from both Z. brachyacanthum F. Muell and Z. veneficum F. Bail.
Abstract: The known substances l-α-canadine methiodide, β-homochelidonine, chelerythrine, isocorydine methiodide (a new alkaloid), lupeol, and hesperidin have been isolated from both Z. brachyacanthum F. Muell. and Z. veneficum F. M. Bail. and it is suggested that these two species are identical. From Z. suberosum C.T. White the recently discovered alkaloid, canthin-6-one, was isolated.
TL;DR: It has been shown that the binding capacity of dissolved serum albumin for methyl orange increases on dilution, and the increased binding capacity implies a change in the protein molecule.
Abstract: It has been shown that the binding capacity of dissolved serum albumin for methyl orange increases on dilution. The increased binding capacity implies a change in the protein molecule. The possible nature of this change is discussed.
TL;DR: The reaction of dimethylamine with 5-methoxy-1,4-naphthoquinone gives approximately equal amounts of the two possible substitution products and with 6-methyl-1.4-Naphthoequinone followed by acid hydrolysis 2-hydroxy-6-methyl l, 4, 4 naphthone is the principal product as discussed by the authors.
Abstract: The reaction of dimethylamine with 5-methoxy-1,4-naphthoquinone gives approximately equal amounts of the two possible substitution products and with 6-methyl-1,4-naphthoquinone followed by acid hydrolysis 2-hydroxy-6-methyl-l,4-naphtho-quinone is the principal product. Similar treatment of 5-methyl-1,4-naphthoquinone gives mostly 3-hydroxy-5-methyl-l,4-naphtlioquinone. The isomer, 2-hydroxy-5- methyl-1,4-naphthoquinone, has been prepared by another method. The product of Thiele-Winter addition of acetic anhydride to juglone is shown to be a mixture of the two possible isomers, but authentic 1,3,4,5-tetra-acetoxynaphthalene has been prepared from 3,5-dihydroxy-1,4-naphthoquinone. The reaction of acetic anhydride with plumbagin gives three compounds, the composition of the mixture depending on the time of contact. Juglone and plumbagin have been selectively brominated in the 6-position and certain other halogen derivatives of these quinones have been prepared. The preparation of 3-chloro-5-hydroxy-2-methyl-1,4-naphthoquinone provides a new route by which droserone may be obtained from plumbagin.
TL;DR: In this article, the Raman and infra-red spectra of methane sulphonyl chloride and methane sulfphonyl fluoride have been measured and the vibrational frequencies of the two molecules have been made; the frequency 377 cm-1 is characteristic of the S-Cl linkage and 1210 cm-F linkage in these compounds.
Abstract: The Raman and infra-red spectra of methane sulphonyl chloride and methane sulphonyl fluoride have been measured. Assignments of the vibrational frequencies of the two molecules have been made ; the frequency 377 cm.-1 is characteristic of the S-Cl linkage and 1210 cm.-1 of the S-F linkage in these compounds. An improved method for the preparation of methane sulphonyl fluoride is described.
TL;DR: In this paper, a study of the kinetics of the diffusion of anhydrous FeC1, in graphite, was made and it was found that this process can be represented for stages between 50 and 100 per cent.
Abstract: A study has been made of the kinetics of the diffusion of anhydrous FeC1, in graphite. I t was found that this process can be represented for stages between 50 and 100 per cent. saturation of the graphite and at temperatures in the range 200 to 360 OC by a relation of the type δc/δt = D(δ2c/δr2 + δc/δ/r), providing the diffusion coefficient D is assigned several values for concentrations of occluded FeCl3 above and below a critical concentration. The value of the latter was found to be about two-thirds the saturation concentration of FeCl3 in graphite, this value apparently being the point at which open hexagonal packing of intercalated ferric ions is complete and a closer hexagonal packing commences. Values of the activation energies of occlusion for concentrations above and below two-thirds saturation were found from the relations of corresponding values of diffusion coefficients to temper- ature. The small difference between these activation energies which were of the order of 2 to 3 kcal is attributed to a cancelling of effects, thus the energy necessary to separate carbon lamellae in early stages of occlusion is offset in later stages by hindrance imposed on diffusing molecules by those already occluded. Reduction of particle size of graphite accelerated the occlusion of FeCl3.
TL;DR: Two closely related water-soluble alkaloids cryptaustoline and cryptowoline iodides have been isolated from the bark of Cryptocarya bowiei (Hook.) Druce.
Abstract: Two closely related water-soluble alkaloids cryptaustoline and cryptowoline iodides have been isolated from the bark of Cryptocarya bowiei (Hook.) Druce. Both have been shown to be derivatives of dibenzo[b,g]pyrrocoline. This constitutes the first isolation of substances containing this nucleus from natural sources.
TL;DR: In this article, a new stereoisomeric form of apo-aromadendrone has been obtained, assisted by the use of infra-red spectra.
Abstract: The reactions of aromadendrene do not agree with either formulae I or II (R=CH2). On the basis of the reactions of apoaromadendrone, assisted by the use of infra-red spectra the formula IV is tentatively proposed. A new stereoisomeric form of apo-aromadendrone has been obtained.
TL;DR: The Raman spectra of benzene, p-chlorobenzene-, p-methoxybenzene-, and o-, m-, and p-toluene sulphonyl chlorides and fluorides and methyl benzene sulphonate are recorded as well as the infra-red absorption bands of liquid benzene chloride and fluoride between 650 and 3100 cm.-l.
Abstract: The Raman spectra of benzene-, p-chlorobenzene-, p-bromobenzene-, p-methoxybenzene-, and o-, m-, and p-toluene sulphonyl chlorides and fluorides and methylbenzene sulphonate are recorded as well as the infra-red absorption bands of liquid benzene sulphonyl chloride and fluoride between 650 and 3100 cm.-l. A frequency c. 375 cm.-1 is characteristic of the S-Cl bond in sulphonyl chlorides and a strong band at c. 1210 cm.-1 is characteristic of the sulphonyl fluoride group. A Raman band at c. 1080 cm.-l in the chlorides and c. 1095 cm.-l in the fluorides appears to be associated with aromatic sulphonyl derivatives. There is such a band at 1094 cm.-1 in the Raman spectrum of methyl benzene sulphonate.
TL;DR: Ngaione has been isolated from the volatile oil of Myoporum acuminatum R.Br. and assigned the formula II as discussed by the authors, and different specimens of the oil contained other ketones.
Abstract: Ngaione has been isolated from the volatile oil of Myoporum acuminatum R.Br. and assigned the formula II. Different specimens of the oil contained other ketones.
TL;DR: The essential oil of Myoporum crassifolium Forst, a shrub endemic to New Caledonia, is shown to consist principally of a tertiary sesquiterpene alcohol which is either identical with or isomeric with synthetic bisabolol as discussed by the authors.
Abstract: The essential oil of Myoporum crassifolium Forst., a shrub endemic to New Caledonia, is shown to consist principally of a tertiary sesquiterpene alcohol which is either identical with or isomeric with synthetic bisabolol.
TL;DR: In this article, the preparation of 2,2,4,6-tetramethyldihydropyridine by the reaction of acetone and ammonia at temperatures of 100-180 °C. has been studied; using an alkaline catalyst at 120°C. for 3 hr, a yield of over 60 per cent.
Abstract: The preparation of 2,2,4,6-tetramethyldihydropyridine by the reaction of acetone and ammonia at temperatures of 100-180 °C. has been studied; using an alkaline catalyst at 120 °C. for 3 hr, a yield of over 60 per cent. can be obtained. This dihydro-pyridine is identical with the product obtained by Matter (1948) in the pyrolysis of 2,2,4,4,6-pentamethyltetrahydropyrimidine Possible mechanisms for its formation are discussed. Catalytic hydrogenation over Raney nickel leads to tetramethyl-piperidine, while with palladium a partial reduction product, formulated as 2,2,4,6-tetramethyl-2,3,4,5-tetrahydropyridine is obtained ; the chemistry of these reduction products has been examined.
TL;DR: From the fruits of Strychnos lucida R.Br, were isolated loganin (1.1 per cent.) which appears to be confined to the pulp, strychnine (0.3 per cent.), and an unresolved glassy alkaloidal mixture as discussed by the authors.
Abstract: From the fruits of Strychnos lucida R.Br, were isolated loganin (1.1 per cent.) which appears to be confined to the pulp, strychnine (0.1 per cent.), brucine (1.3 per cent.), and an unresolved glassy alkaloidal mixture (0.5 per cent.). " Lucidine-S " could not be separated. The leaves of 8. psilosperma F. Muell. contain about 1.1 per cent. total alkaloid from which two new alkaloids, strychnospermine and spermostrychnine, were isolated. Structural formulae for these are suggested on biogenetic grounds. The triterpene alcohol, germanicol, was also isolated from S. psilosperma leaves.
TL;DR: The bark of Gyrocarpus americanus Jacq. contains 0.4-0.6 percent phaeanthine and 0.7 percent dmagnocurarine.
Abstract: The bark of Gyrocarpus americanus Jacq. contains 0.4-0.6 per cent. phaeanthine and 0.6-0.7 per cent. of the quaternary base d-magnocurarine. The leaves contain 0.03 per cent. phaeanthine only.
TL;DR: In this article, a one electron reduction mechanism involving the hydroxyl radical and either the oxygen atom or the oxygen molecule is discussed, in order to explain the nature of the A.C. and D.C polarograms.
Abstract: Investigations of the A.C. and D.C. polarography of oxygen in neutral and alkaline media have shown that the reduction process is univalent and reversible. It has also been shown experimentally that hydrogen peroxide is reversibly oxidized to oxygen in the presence of alkali. In order to explain the nature of the A.C. and D.C. polarograms, thus obtained, a one electron reduction mechanism involving the hydroxyl radical and either the oxygen atom or the oxygen molecule is discussed.
TL;DR: The bark of Medicosma cunninghamii Hook contains approximately 0.06% of the alkaloid C17H15O3N which has been named medicosmine and shown to be a 2,3-furoquinoline with a dimethylpyran ring fused in either the 5,6- or 6,7-positions (III or IV) as discussed by the authors.
Abstract: The bark of Medicosma cunninghamii Hook. f. contains approximately 0.06 per cent. of an alkaloid C17H15O3N which has been named medicosmine and shown to be a 2,3-furoquinoline with a dimethylpyran ring fused in either the 5,6- or 6,7-positions (III or IV). It has been degraded to acetone, acetaldehyde, and a phenol which when methylated and oxidized gives 6-methoxy-4-hydroxy-1-methyl-2-quinolone, and 6- and 7-methoxy-4-hydroxy-1-methyl-2-quinolones have been synthesized for comparison. A dihydropyrano-4-methoxy-3-ethyl-2-quinoone is formed by hydrogenolysis of the furane ring. Further examples are reported of the preparation of isatins from 3-nitroso-2,4-dihydroxyquinolines.
TL;DR: Simultaneous potential and surface conductivity measurements have been made on three samples of cassiterite in water, in solutions of HCl, alkalis, inorganic salts, and the flotation collector reagent sodium cetyl sulphate as mentioned in this paper.
Abstract: Simultaneous ζ-potential and surface conductivity measurements have been made on three samples of cassiterite (SnO2) in water, in solutions of HCl, alkalis, inorganic salts, and the flotation collector reagent sodium cetyl sulphate. It is probable that the intrinsic surface charge of cassiterite in water is negative and that it is due to surface ionization as a very weak acid. Two of the solids possessed a negative surface whilst the positive charge of the third seemed to be due to ionization of a strongly basic impurity. Those samples having a negative charge showed little reaction with sodium cetyl sulphate alone, but appreciable adsorption of cetyl sulphate ion took place in acid solution. On the other hand, the sample with the positive surface reacted with cetyl sulphate ion even in the absence of acid. In all cases adsorption of cetyl sulphate was completely reversible.
TL;DR: In this article, it was shown that the conjugate acid of N-methylacridan can be oxidized by indophenol anion at a rate 19 times higher than the uncharged indophenols.
Abstract: The rates of oxidation of N-methylacridan by 2,6-dichlorophenolindophenol have been measured between pH 2.74 and 6.91 at 20 to 22 °C in the presence of 8 to 22 per cent. ethanol. The reaction was of the second order and was found to proceed by ' two simultaneous mechanisms, both involving the conjugate acid of N-methylacridan. The oxidation of this cation by the indophenol anion proceeded at a rate which was 19 times greater than the oxidation by the uncharged indophenol molecule. It is shown that oxidation probably occurs by hydrogen atom transfer rather than electron transfer. A similar mechanism for the oxidation of dihydro-coenzyme I would account for its slow reactivity towards molecular oxygen and the biological necessity for mediating systems involving both hydrogen atoms and electrons.