Naphthalene Nuclei Research Articles

Investigation of σ receptors agonist/antagonist activity through N-(6-methoxytetralin-1-yl)- and N-(6-methoxynaphthalen-1-yl)alkyl derivatives of polymethylpiperidines

A series of polymethyl-substituted piperidines linked to either a 6-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl or a 6-methoxynaphthalen-1-yl moiety was generated with the aim of verifying a previously generated hypothesis: tetralin and naphthalene nuclei confer opposite activity at the σ1 receptor. Compounds 6, 9 and 10 displayed appreciable affinity at both σ subtypes, but none of the novel compounds displayed significant antiproliferative activity in MCF7wt and MCF7σ1 cell lines. The effect on bradikynin-triggered Ca2+ mobilization was studied as a methodology to suggest σ receptors mediated activity.

The synthesis of the pyranonaphthoquinones dehydroherbarin and anhydrofusarubin using Wacker oxidation methodology as a key step and other unexpected oxidation reactions with ceric ammonium nitrate and salcomine

The synthesis of two closely related pyranonaphthoquinones, dehydroherbarin and anhydrofusarubin, is described. The construction of the naphthalene nuclei was achieved using the Stobbe condensation reaction using 2,4-dimethoxybenzaldehyde and 2,4,5-trimethoxybenzaldehyde as their respective starting materials. Two key steps en route include a PIFA-mediated addition of a methoxy substituent onto the naphthalene skeleton and a Wacker oxidation reaction to construct the benzo[g]isochromene nucleus. Two interesting oxidation reactions of the intermediate isochromene enol ether of 7,9-dimethoxy-3-methyl-1H-benzo[g]isochromene-5-ol were observed. Treatment of the substrate with salcomine resulted in the formation of (3-formyl-4-hydroxy-6,8-dimethoxynaphthalene-2-yl)methyl acetate, while treatment of the same substrate with CAN resulted in the formation of racemic (3R,4R)-3-hydroxy-7,9-dimethoxy-3-methyl-5,10-dioxo-3,4,5,10-tetrahydro-1H-benzo[g]isochromen-4-yl nitrate.

Polyvariant modification of di- and tetrahydroxydinaphthylmethanes

Modification of di- and tetrahydroxydinaphthylmethanes yielded a new family of aromatic systems differing by the nature, the number, and positions of functional groups and by the mode of fusion of the naphthalene nuclei. The effect of the starting dinaphthylmethane structure on the modification route was demonstrated.

Synthesis and Structural Elucidation of Sulfonated Naphthalene-Formaldehyde

The synthesis, characterization, structural elucidation, and application of the dispersant obtained from the condensation of β -naphthalene sulfonic acid and formaldehyde are reported. The one-pot synthesis from naphthalene, sulfuric acid, and formaldehyde leads to reproducible polymers with 13 and 14 naphthalene nuclei. The 1 H and 13 C NMR spectra in D 2 O (representative spherical shape) and DMSO (representative rod-like shape) are reported. The belching technique led to excellent super pure material.

Synthesis and Structural Elucidation of NSC Auxiliary Dispersing Agents

The synthesis, characterization, structural elucidation, and application of the dispersant (NSC) obtained from condensation of β-naphthalene sulphonic acid and formaldehyde are described. The one pot process from naphthalene, sulphuric acid, and formaldehyde leads to reproducible condensate products with n = 13 and 14 naphthalene nuclei. The 1H and 13C NMR spectra were recorded in D2O (representative spherical shape) and DMSO (representative rod-like shape). Bleaching leads to the recovery of excellent super pure material.

1,2-Bis(3,5-dimethylpyrazol-1-yl)-anti-[2.2]paracyclonaphthane

The title compound, C34H33N4, is a new 3,5-di­methyl­pyrazole-substituted para­cyclo­naphthane. Each of the two symmetry-independent mol­ecules in the asymmetric unit occupies a special position on a twofold axis and exhibits an intramol­ecular π–π stacking interaction between the naphthalene moieties. The geometry of both mol­ecules is essentially the same, the bridged rings of the naphthalene nuclei being deformed into a boat shape.

A chemometric approach to understanding the bioelimination of anionic, water-soluble dyes by a biomass using empirical and semi-empirical molecular descriptors

Single correlation and multiple linear regression analyses have been applied to understand the bioelimination of 103 anionic, water-soluble dyes by a biomass at a wastewater treatment works. The chemometric approach highlighted that anionic, water-soluble dyes with larger molecular size/ionic charge ratios and containing more primary aromatic amines and unsulphonated naphthalene nuclei and fewer aliphatic alcohol groups had superior levels of bioelimination.

Composition of chloronaphthalene congeners in technical chloronaphthalene formulations of the Halowax series

Normalised pattern (DB‐5 capillary column) of polychlorinated naphthalenes (PCNs; CNs) for all seven technical Halowax formulations and mass percent contribution (CN %) for an equivalent mixture of Halowax 1031, 1000, 1001, 1099, 1013, 1014 and 1051 (Equi‐Halowax) is presented. 2,3‐DiCN (PCN no. 10), 1,6,7‐and 2,3,6‐TrCNs (PCNs nos 25 and 26) and probably also 1,3,5‐TrCN (PCN no. 19), 1,3,6,7‐, 1,2,3,6‐and 1,2,3,8‐TeCN (PCNs nos. 44, 29 and 31), and 1,2,3,6,7,8‐HxCN (PCN no. 70) were absent in commercial PCNs formulations. The congeners such as 1,2,3‐TrCN (PCN no. 13), 1,3,8‐TrCN (PCN no. 22) and 1,2,3,6,7‐PeCN (PCN no. 54) were present in the mixtures at very low concentrations. The congeners most abundant in Halowax mixtures are usually chlorinated at α‐positions (1, 4, 5, 8‐positions) of the naphthalene nuclei. Because of some unresolved peaks observed on the chromatograms due to insufficient separation power of DB‐5, and also of many other liquid phases used in capillary gas Chromatographie separation of PCNs even when mass spectrometric detection was used, a perfect isomer and congener composition of PCN mixtures still has to be elucidated.

Bent aromatic rings in naphthalene derivatives

X-Ray crystallography and dynamic 1H NMR spectroscopy have revealed that 1,4,5,8-tetramethyl-, 1-bromomethyl-4,5,8-trimethyl-, and 1,8-bis(bromomethyl)-4,5-dimethyl-2,3,6,7-tetrabromonaphthalene — 3, 4, and 5, respectively — have severely distorted naphthalene nuclei in the solid state that also correspond to the gross conformations that occupy appreciable (Δ G‡∼16 kcal mol −1) energy wells in the solution state.

Induced circular-dichroism spectra of complexes of cyclomalto-oligosaccharides and azo dyes containing naphthalene nuclei

In the circular-dichroism spectra of inclusion complexes of 7 types of cyclodextrin (CDs) with 6 kinds of azo dyes containing the naphthalene nucleus, the direction of inclusion and the stacking mode may be elucidated from patterns in the u.v. and the first π→π * regions. The patterns in the former region indicate that the naphthalene fragment in almost all of complexes is incorporated equatorially into the cavity. Those azo dyes that have a tight fit in the CD cavity exhibit exciton interaction between two molecules of the chromophoric dye included in the complexes. The spectral pattern changes in sign according to the inclusion mode of the guest molecules and the angle between the chromophores. For example, the spectral pattern of the Orange II-cyclomaltoheptaose (β CD) complex indicates that the naphthalene nucleus is included axially, and that the angle between two molecules of the azo dye is >90°. On the other hand, the spectral pattern of the Croceine Orange-DM-β CD complex indicates equatorial inclusion and a stacking angle of <90°. The most important driving force for the host-guest interaction is van der Waals attraction; hydrogen bonding is not significant.

Crystal and molecular structure of a segment of a stacked face-to-face ferrocene polymer

The crystal and molecular structure of a fragment of a face-to-face metallocene polymer, the [2,3]-oligomer( 2a, n = 2) of 1,8-diferrocenylnaphthalene( 1a), has been determined in order to better define the structural features of the polymer. The molecular structure of this compound shows the same form and magnitude of molecular distortions as those found in the monomeric unit 1a. An unusual feature of the oligomer is the cis arrangement of the two naphthalene nuclei, which brings several of the carbon centers on each naphthalene ring in close proximity. These structural aspects are discussed in the context of possible structures for the related polymer.

Determination of Total Gossypol in Cottonseed and Cottonseed Meals by Derivative UV Spectrophotometry

A new method for the determination of total gossypol in cottonseed and cottonseed meals has been developed. The method involves oxalic acid hydrolysis of the bound gossypol in a methyl ethyl ketone-water azeotrope, partitioning the liberated gossypol into chloroform, and quantification by 2nd derivative UV spectrophotometry. The 2nd derivative transformation and measurement of the conventional analytical band around 300 nm permits direct quantification of all compounds containing naphthalene nuclei; chromogenic reaction is not required. The method was tested at concentration levels of total gossypol normally expected for cottonseed and cottonseed meal. Precision and accuracy data suggested an overall relative standard deviation of 4.0% and an overall recovery of 89.5%. Although results for cottonseed and solvent-extracted cottonseed meal analyses were comparable to those obtained by use of American Oil Chemists' Society methods, results were lower for screw-pressed meals. The lower results were attributed to the partial conversion of gossypol, during the cooking process of these meals, to compounds that differ in composition and structure from gossypol and which react with aniline to give false readings.

Binding of a non-ionic azo dye by sodium salt of .BETA.-naphthalenesulfonic acid-formaldehyde condensates - Effect of the degree of the condensation on the binding equilibrium.

The binding of a model azo disperse dye by β-naphthalenesulfonic acid and formaldehyde condensates (βNSF) in water was discussed. The binding constants, K, for the bidding by βNSF with different degrees of condensation, N=2, 3, 4, 5, 7.2, 12 and 40 were determined spectrophothometrically. The thermodynamic parameters, the enthalpy change, ΔH° and the entropy change, ΔS° calculated from the values of K in the temperature range 15-40°C revealed following facts.The value of K increases with N up to N=ca. 10 and then level off gradually. This is ascribed to an increase in ΔS° with N; the value is negative for βNSF with N=2, 3 and 4 but it becomes positive for βNSF with N=12, 40 under the low concentration of added salts. The value of ΔH° is negative irrespective of N but its absolute value decreases with the increase in N.The increase in the concentration of added salts gives no appreciable change in the thermodynamic parameters for βNSF with N=3 but for βNSF with N=12 and 40, the increase gives significant changes in the parameters; both values of ΔH° and ΔS° decrease significantly. These results may be explained in terms of the conformational change of polyelectrolytes. βNSF with N=12 and 40 behave as a typical polyelectrolyte; their conformation varies from an expanded form to a compact one on addition of electrolytes. The extended conformation is favorable for the hydrophobic interaction between the linear dye and successive naphthalene nuclei of βNSF with a high degree of the condensation. The increase in the value of ΔS° with N may be explained in terms of the contribution of the hydrophobic bonding to the binding.

Supercritical-gas extraction of Turkish coking coal

Treatment of Zonguldak coal with toluene at 360 °C gave yields of extract which increased from 19–32% as the pressure of the extraction was increased from 11.6 to 29 M Pa. These yields were similar to those previously obtained by supercritical-gas extraction of lignites but the composition of the extracts differed. The lignite extracts contained a much higher proportion of petroleum ether-soluble material and only half the proportion of material insoluble in both petroleum ether and benzene than the Zonguldak coal extract. Benzene, biphenyl, naphthalene, phenanthrene, pyrene, benzoanthracene and be-nzophenanthrene nuclei were identified in the coal extract. Comparison of the yields of substituted benzenes with those obtained by low-temperature carbonization suggests that the proportions of different substitution pattern is determined by the structure of the fuel. Less naphthalene nuclei were found than expected but relatively large yields of biphenyls were obtained which were attributed to their formation from toluene in the presence of phenols.

Manifestation of the Jahn-Teller effect in the EPR spectra of naphthalenecyclopentadienyliron

The anisotropic EPR spectrum of C 10H 8FeC 5 undergoes Jahn-Teller effect induced transition to the isotropic spectrum at 123 K in the solid phase. Iron atom tunnelling between the naphthalene benzene nuclei may serve as a model of motion averaging g-factor anisotropy. The model is confirmed by studies of the α-MeC 10H 7FeC 5H 5 and β-FC 10H 7FeC 5H 5 EPR spectra. The latter two compounds show splitting of the g | signals into two components corresponding to dissimilar isomers at temperatures above 77 K. The isomers differ in the mode of iron bonding with the substituted and unsubstituted naphthalene nuclei.

DINAPHTHO[2,1-h 1′,2′-n]-5,18-DI-t-BUTYL-1,3,10,12-TETRADEHYDRO[l8]ANNULENE AND RELATED COMPOUNDS. THE EFFECT OF POSITION OF ANNELATION ON THE DIATROPICITY OF ANNULENE RING

Abstract Dinaphtho-di-t-butyltetradehydro[18]annulene (X) was prepared in order to clarify the effect of annelation on the diatropicity of dehydroannulenes containing formal acetylene and cumulene in the cyclic system. It was found that the diatropicity of X is strongly suppressed by fusion with two naphthalene nuclei in contrast to strongly diatropic dinaphtho-di-t-butyldidehydro[l4]annulene (III). The result indicates that equivalent Kekule structures exert prominent effect on the delocalization of π-electrons in annelated annulene. The preparation of bis(dihydronaphtho)- (VIII) and naphtho-dihydronaphtho- (XII) analogues as reference compounds was also described.

Antioxidant properties of fractions of aromatic hydrocarbons isolated from transformer distillates of low-sulfur petroleums

1. High antioxidant properties of fractions containing phenanthrene structures were established on the basis of a complex investigation of antioxidant properties and the hydrocarbon composition of narrow fractions of Chromatographie separation of transformer distillates from low-sulfur petroleums. 2. Fractions not containing phenanthrene structures and consisting mainly of hydrocarbons containing benzene and naphthalene nuclei in concentrations characteristic for transformer oils have a weak stabilizing effect in relation to paraffin-naphthene hydrocarbons of the oils. 3. The low stability of noninhibited transformer oils from Anastas'evskii petroleum is due to the hydrocarbon composition of the raw material and not to insufficiencies of other used processes (adsorption, acid-base purification).

Coupling of Naphthalene Nuclei by Lewis Acid Catalyst—Oxidant1

Coupling of Naphthalene Nuclei by Lewis Acid Catalyst—Oxidant¹

Propriétés physico-chimiques de dérivés à caractère aromatique—III: Position et intensitié des vibrations de valence ν CO et ν CN dans une série d'esters et de nitriles polycycliques aromatiques

A linear relation between the ν CO or ν CN frequencies and a or, the atomic orbital coefficient in the non-bonding molecular orbital of the parent odd alternant radical, has been observed in a series of aromatic esters and nitriles. The equations of the straight lines are ν CO = (1693 + 36.9 a or) cm −1 ν CN = (2190 + 55.6 a or) cm −1 Steric strain due to peri-hydrogens seems to have no influence on the frequencies. The intensities of the ν CO and ν CN vibrations depend on: (a) the steric strain due to peri-hydrogens (b) the number of rings in the aromatic nucleus (c) the conjugating power of the position bearing the substituent. It is also suggested that the conjugation between the benzene and naphthalene nuclei in fluoranthene is very reduced, in the electronic fundamental state.

Absorption Spectra of Dyes. VII. Some Steric Effects and Auxochrome-Effects on Complex Formation

Abstract 1. The absorption spectra of the dyes prepared by coupling disazotized 2S-, H-, chromotropic, NW-, γ- and J- acid with dianisidine, and of their copper derivatives were observed in aqueous solutions of the binary mixture with Chrysophenine G, and were compared with the sum curves of the component absorption spectra. 2. The order of the equilibrium constants for a 1:1 complex formed between the dyes not containing copper and Chrysophenine G was parallel to the respective values of the difference in wave number (Δν cm−1) between maximum positions in the region of 390∼420 mμ of the curve simply added and that observed with the equimolar binary mixture of about 1×10−5mol./1.; it was also parallel to those of the decreasing ratio in optical density (ΔD⁄D) of the mixed system at the first maximum position of the sum curve. 3. Under the same conditions as above, Δν and ΔD⁄D were also determined for the mixture of the copper derivatives and Chrysophenine G. In this case, the copper derivatives of 2S-, H-, and chromotropic acid, in the presence of effective auxochromes, still revealed large values of Δν (ca. 1000 cm−1) and ΔD⁄D (ca. 15%), while the values for the rest of the derivatives were almost zero. 4. Discussing the above results, it was shown that in order to display a spectral change due to the formation of a 1:1 complex in a binary mixture with Chrysophenine G, it is necessary that the partner dye has effective auxochromes (amino, hydroxyl) as terminal groups of a conjugated system. It was also shown that the sulfonic groups which are attached to the terminal naphthalene nuclei act on the structure of the dye itself as a steric factor rather than as an electric effect (repulsion) between the ionic charges in the groups and those of Chrysophenine G, and that the more planar structure, resulting in a smaller steric effect, produces more complex.