Phenyl Nucleus Research Articles

The protective action of antioxidants and their complex-forming characteristics

Inclusion complexes of 2-(2′-aryl-1,3-indandion-2′-yl)-1,4-naphthohydroquinones with methanol, benzene and ethylbenzene have been prepared and their composition in relation to the substituent on the phenyl nucleus has been determined. The inhibition of oxidation of SKS-30 rubber by these derivatives of 1,4-naphthohydroquinone and their rates of oxidation in methanol by oxygen have been compared by the Warburg method. On the basis of the results so obtained it is suggested that the antioxidant activity of these hydroquinones is not connected with complex formation and that there is no direct relationship between the oxidizability of an antioxidant and its protective effect.

1,3,5-Triazines. Part XII. The reaction of trichloro-1,3,5-triazine (cyanuric chloride) with N-phenyl-pyrrole, -indole, -carbazole, and -diphenylamine, and N-ethyl-pyrrole, -carbazole, and -diphenylamine

The reactions of trichloro-1,3,5-triazine (cyanuric chloride) with N-phenyl-pyrrole, -indole, and -carbazole, with N-ethyl-pyrrole, and -carbazole, and, for comparison purposes, with ethyldiphenylamine and triphenylamine have been investigated. The reaction with N-substituted pyrrole and indole yields products substituted at the 2- and 3-position respectively of the five-membered ring. N-Ethylcarbazole gives a ‘carbon’ product substituted at the 3-position and a ‘nitrogen’-substituted product whilst N-phenylcarbazole gives two ‘carbon’ derivatives substituted on the benzo and phenyl nucleus respectively. Ethyldiphenylamine gives a ‘para-carbon’-substituted and a ‘nitrogen’-substituted derivative whilst triphenylamine yields a single ‘para-carbon’-substituted derivative.

Oxovanadium(IV) Complexes of Schiff Bases Obtained from Salicylaldehyde Derivatives and Arylamines

Abstract Oxovanadium(IV) complexes of Schiff bases obtained from salicylaldehyde derivatives and arylamines (abbreviated as VO(X-SAL.R)2) have been synthesized, where X=H, 5,6-benzo, 5-Cl, and 5-Br, and R=Ph, CH3-Ph, 2,6-(CH3)2-Ph and 2,6-(C2H5)2-Ph, Ph being phenyl nucleus. Complexes of the type VO(5-X-SAL.Ph)2 in the solid state, X being Cl and Br, consist of the species having a different configuration from that of the other complexes. For the latter complexes, distortion from the square-pyramidal configuration is not apparent in the solid state or in non-donor solvents, but in pyridine they combine with one pyridine molecule to form six-coordinate vanadium(IV) complexes. Comparison shows that the tendency toward the distortion in the solid state is lower with R=aryl than with R=α-branched alkyl groups.

Effect of coordination with the metal on the reactivity of π-bonded organic ligands: III. Change of the electronic effect of the phenyl nucleus upon coordination with the Cr(CO) 3-group

Ferrocenylphenylchromiumtricarbonylmethane (I) and ferrocenylphenylchromium tricarbonyl (II) were prepared. The polarographic oxidation of (I) and (II) on a platinum electrode in CH 3CN was investigated and the E fo of (I) was determined by a potentiometric titration. A set of σ-constants was calculated for the (CO) 3CrC 6H 5-group as substituent. Analysis of the results obtained led to the conclusion that a considerable change of effective positive charge on the σ-orbitals of the aromatic ring carbons took place upon coordination with the (CO) 3Cr-gro´up.

Mercuration of thiazole derivatives

Conditions have been found for the mercuration of alkyl- and aryl- thiazoles. Mercuration takes place in position 5 of the ring, if it is free, and does not depend on the nature of the substituent in position 2. The possibility of the mercuration of a trisubstituted thiazole has been shown for the first time. When a phenyl radical is present in position 2, the mercury ion enters the para position of the phenyl nucleus.

Lipolytic activity of structurally related agonists in rat epididymal fat tissue in vitro

Utilizing the rat epididymal fat pad, the rates of free-fatty acid (FFA) release were quantitated in the presence of various concentrations of agonists. The calculation of intrinsic activity and affinity constants from standard dose-response relationships and double reciprocal plots were employed to establish the structure-activity relationships. Marked changes in the affinity, and to a lesser degree, in the intrinsic activity constants of phenethylamines for the adrenergic-adipose tissue receptor system were produced by alterations of the (a) side chain nitrogen, (b) α- and β-carbon substituents and (c) meta- and para-ring positions of the phenyl nucleus. While optimal activity was possessed by all catecholamines, results with certain noncatecholamines indicated that the catechol moiety was not obligatory for FFA mobilization. The presence of a phenolic group in either ring position was sufficient to produce a maximal response when the β-carbon atom was also hydroxylated. In addition to β-hydroxylation, N-substitution of a bulky alkyl or aralkyl group greatly enhanced the lipolytic activity of the phenethylamine molecule. Optimal activity was obtained with either primary or secondary amines, whereas tertiary amines were characterized as having a decreased affinity. Furthermore, the presence of a β-keto or α-ethyl substituent on the ethylamino-side chain decreased the ability of the agonist to release FFA from adipose tissue in vitro.

Wurtz-Fittig syntheses of mixed trideuteromethyl and methyl derivatives of benzene

In the Wurtz-Fittig reaction of an aryl bromide with methyl iodide no rearrangement products are produced. All reaction mechanisms involving radical intermediates are contrary to experimental results and should be rejected. Selective or even specific adsorption dominates the sequence of the Wurtz-Fittig reactions: Aryl tribromide ⪢ aryl dibromide ⪢ aryl monobromide ⪢ alkyl iodide, although chemical reactivity with sodium is in the reverse order, the higher ranking molecule reacting much slower. This effect may be important in other surface-localized reactions also. By the method described, it is possible to introduce any number of trideuteromethyl groups at predetermined locations in the phenyl nucleus. Thus fifteen trideuteromethyl derivatives and mixed trideuteromethyl and methyl derivatives of benzene have been prepared (see Tables).

Untersuchungen über die Struktur von Formazanen I. 15N‐H‐Kopplung des Chelatwasserstoffatoms

Abstract15N‐H‐Coupling in 1, 3, 5‐triphenylformazan derivatives demonstrates that these compounds are not resonance hybrids but tautomeric pairs. The position of the tautomeric equilibrium is a function of the substituents present in the phenyl nuclei on N‐1 and N‐5.

The infra-red spectra and structure of the rare-earth benzoates

The i.r. absorption spectra for benzoic acid and the benzoates of Na, Pr, Nd, Er, and Tm have been measured over the frequency range 3400−200 cm −1. Frequencies for the rare-earth benzoates are reported for the first time. Previously published data and observations made in this research are used to suggest several band assignments. The CC and CH bands of the phenyl nucleus are not greatly changed in the lanthanon salts. The various bands associated with the carboxylate group motions are considerably altered in the salt. The modifications of several of the bands are interpreted to indicate the benzoate ion is serving as a bidendate ligand, and the lanthanon ion is 6-co-ordinated in lanthanon benzoates. Such an interpretation accounts for some of the properties of these benzoates such as: solubility, ease of dehydration, and conductance. Benzoic acid, sodium benzoate, the light lanthanon benzoates, and the heavy lanthanon benzoates can be distinguished from each other in terms of their i.r. spectra. The bands useful for such distinctions are reported.

Sulphonation of arylpyrazoles. Part II. Some 1-phenylpyrazolesulphonic acids and their derivatives

1-Phenylpyrazole is sulphonated by oleum principally in the para-position of the phenyl nucleus, whereas chlorosulphuric acid in chloroform solution sulphonates it in the 4-position of the pyrazole nucleus. By increasing the severity of the conditions, substituents can be introduced at both reactive sites to give disubstituted derivatives. The chemical evidence for the structures of these compounds is supported by n.m.r. spectra.

Integral intensities of the carbonyl bands in the IR spectra of heteroannularly substituted esters of ferrocenecarboxylic acid

1. The integral intensities of the carbonyl bands in the IR spectra of 13 heteroannularly substituted esters of ferrocenecarboxylic acid have been measured. 2. The transannular influence of substituents is approximately half that of the same groups in the para position of a phenyl nucleus. At the same time, the +C effect of electron-donating substituents in the esters investigated is smaller than in the analogous benzene derivatives.

Basicity of ketones of the cyclopentadienyl-tricarbonylmetal series

1. The basicities of a series of ketones of the cyclopentadienyltricarbonylnietals (M=Mn or Re) in aqueous sulfuric acid have been measured. 2. The magnitudes of σ+ for the cyclopentadienyltricarbonylmanganese and cyclopentadienyltricarbonylrhenium residues have been calculated. With respect to their total electronic influence under the conditions of the protonization of the neighboring carbonyl group, they are approximately equal to one another and possess electron-donating properties stronger than those of a phenyl nucleus.

Doubling of the methyl doublet in some isopropyl compounds with an asymmetric centre

AbstractThe methyl resonance patterns of some isopropylcarbinols and isopropyl esters are described and discussed. The important influence of a phenyl nucleus on these patterns is obvious. The presence of such a nucleus as well as that of an asymmetric centre is a prerequisite for doubling of the methyl doublet in the case of the esters. It could not be established whether the doubling is due to intrinsic asymmetry, to preferential conformations, or to both factors.

Charge‐transfer complexes of non‐coplanar derivatives of 4,4′‐dimethoxystilbene and of cis‐trans isomer pairs of substituted stilbenes

AbstractCharge‐transfer absorption spectra of tetracyanoethylene complexes with a number of stilbene derivatives as donor molecules (1‐15, Table 1) have been measured in dichloromethane as solvent. Job tests showed that the complexes present in the solutions must be 1 : 1 complexes.All curves show two absorption maxima. The longest wavelength absorption band has been ascribed to a complex in which the complete stilbene molecule acts as the electron donor. Its position varies with increasing lack of coplanarity of the donor molecule. The other peak may belong to a configuration in which one of the aromatic rings in the stilbene molecule is the donating part. Values of the equilibrium constants (K) and extinction coefficients (ϵ) of the charge‐transfer complexes have been derived from Benesi‐Hildebrand graphs. A statistical analysis of the results has been given in the appendix. In the series of alkylated 4,4′‐dimethoxystilbenes (1–9) K decreases with increasing hindrance of coplanarity reaching a nearly constant value when the angle of twist of the phenyl nuclei in the stilbene component becomes large. Parallel to this decrease the character of the charge‐transfer absorption seems to change from complex to contact charge‐transfer.Finally the existence of linear relationships between ionisation potentials of donors or electron affinities of acceptors and vmax of their charge‐transfer absorptions has been tested.

Interactions of aryl esters in the tropine and ψ-tropine series with tissue chemoreceptors. The ortho effect. VII

Studies on toxic properties of substituted phenylacetic esters in the tropine and ψ-tropine amino alcohol series have revealed a subtle “ortho effect” in ester-chemoreceptor interactions. Receptors in the isolated rat phrenic nerve-diaphragm preparation and at the catalytic locus on acetylcholinesterase are quite sensitive to tropine vs. ψ-tropine configurations in esters bearing ortho, meta, or para substituents on the phenyl nucleus. In contrast, receptors mediating convulsive death in the mouse are fully as sensitive to ring stereochemistry in esters bearing m- or p-substituents, but lose their ability to discriminate between topine and ψ-tropine structure when the phenyl group is substituted in ortho position. This latter finding is independent of the electronic character of the substituent in ortho position, but appears to be related to a requirement for a certain minimum steric bulk of that substituent. These results are interpreted in terms of possible modes of attachment of the aryl esters to central and peripheral chemoreceptor surfaces.

Die ultraviolett-absorptionsspektren einiger aromatischer Phosphoniumhalogenide

The UV absorption spectra of aromatic phosphonium halides are discussed and compared with the spectra of phosphine oxides, halophosphoranes, aromatic amine oxides and of tetraphenyl onium derivatives of As and Sb. All these compounds have similar spectra which show no more resonance between the phenyl nucleus and the lone pair electron of group Vb atoms, which characterizes the spectra of the corresponding trivalent compounds.

Synthesis and Investigation of Polynuclear Alkyl-Polyphenyl Hydrocarbons as Potential High Temperature and Radiation-Resistant Fluids.

The liquid range of thermally and radiation-stable polyphenyl compounds, e.g., biphenyl and terphenyl, can be widened by alkylation and isomerization of the phenyl nuclei. However, some sacrifices in other desirable properties, e.g., thermal and radiation stability, are also en tailed. An extensive study of the effects of various substituents on the properties of biphenyl and the terphenyls indicates that the best compromises between the desirable properties can be attained in the 3-heptyl-m-terphenyl and 4' -heptyl-m-terphenyl derivatives. A comparison is made between the alkylated polyphenyls and other radiationresistant compounds, such as the polyaryl ethers. (D.L.C.)

Synthesis of isocoumarin‐3‐carboxylic acids

Abstract2‐Carboxyphenylpyruvic acid and its derivatives with substituents in the phenyl nucleus can be prepared via a modified azlactone synthesis. These phenylpyruvic acids display a spontaneous ring closure into the corresponding isocoumarin carboxylic acids.

Nuclear methylation of chalkones and flavanones

Nuclear methylation of 2:4-dihydroxy-chalkones (III) give rise to 3-C-methyl derivatives just as in the case of resacetophenone. C-Methylchalkone-derivatives (IV) with substituents in the side phenyl nucleus have also been prepared by this method. For comparison, they have been synthesised using 3-methyl-peonol and appropriate derivatives of benzaldehyde. C-Methyl-iso-liquiritigenin-dimethyl-ether (IVb) was cyclised to the corresponding 8-methyl-flavanone (VI).

Some actions of substituted choline phenyl ethers, particularly of choline 2:6-xylyl ether.

Marked nicotine-like stimulant properties are possessed by choline phenyl ether and choline o-tolyl ether, and to a decreasing extent by choline 2:6-xylyl ether and choline 2:4:6-mesityl ether. The compounds all show neuromuscular blocking properties, which are of short duration and pass from mainly decamethonium-like to mainly curare-like as more methyl groups are added to the phenyl nucleus. This series of compounds also possesses muscarinic, weak anti-adrenaline and vasodilator properties, as well as long-lasting local anaesthetic effects in the two compounds tested by intradermal injection.