Determination of the composition of hydrogenation products from nitrogenous heterocyclic compounds by gas chromatography-mass spectrometry

Summary The composition of the products of high-pressure hydrogenation on MoS₂ catalyst of heterocyclic compounds (pyridine, quinoline, isoquinoline, 2-methylpyrrole) belonging to the types of compounds currently occurring in the fractions of petroleum and in similar products was determined by GC-MS. The change of composition of these products with different temperatures was investigated.

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Bestimmung der Zusammensetzung der Hydrierungsprodukte heterocyclischer Stickstoffverbindungen durch GC-MS

Zusammenfassung Die Zusammensetzung der Produkte der Hochdruckhydrierung (MoS₂-Katalysator) heterocyclischer Stickstoffverbindungen (Pyridin, Chinolin, Isochinolin, 2-Methylpyrrol), wie sie in Erdölfraktionen und ähnlichen Erzeugnissen vorkommen, wurde untersucht und diskutiert. Änderungen der Zusammensetzung in Abhängigkeit von der Temperatur wurden ebenfalls berücksichtigt.

     

Solid state reactions of nitrogenous heterocyclic compounds (II)

Solid state Michael addition reaction of indole with α, β-unsaturated carbonyl compounds was carried out, by which a series of compounds containing three different heterocyclic groups binding to one carbon atom were ob-tained. In the presence of Lewis acid, indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones. The solid state reaction showed higher selectivity and yield than solution reaction. The structures of products were identified by IR,¹H NMR, MS. elemental analysis and X-ray crystal analysis. The reac-tion mechanism was also proposed. Project supported by the National Natural Science Foundation of China     

Mass spectrometry and stereochemistry of heterocyclic compounds (review)

The possibilities of the application of mass spectrometry for the determination of the orientation of substituents, the stereochemistry of ring fusion, and the configuration of an asymmetric heteroatom are examined. The possibility of the use of the differences in the ionization and appearance potentials of epimers for the solution of stereochemical problems in series of heterocyclic compounds is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1460, November, 1978.     

Synthesis of hydrogenated heterocyclic compounds by the addition of nucleophilic reagents to semicyclic α-methenyl 1,5-diketones

The addition of primary and secondary amines and hydrogen cyanide to semicyclic -methenyl 1,5-diketones of the 1,3-diphenyl-1-(2-oxocyclohexyl)-2-methenyl-3-propanone type leads, respectively, to compounds with hydrogenated quinoline, -flavenone, and chroman structures.Communication XXIV from the series Reactions of 1,5-Diketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1356–1360, October, 1977.     

Synthesis and NMR spectral assignments of novel nitrogen and sulfur heterocyclic compounds

Synthesis and NMR spectral studies of multidentate N and S heterocycles, 1,3,5-tris(N-methylbenzimidazolyl)benzene, 1,3,5-tris(benzimidazolyl)benzene,1,3,5-tris(benzothiazolyl) benzene, 2,2'-bipyridine 3,3'-bis(benzothiazolyl)benzene and 1,2,4,5-tetrakis(benzothiazolyl) benzene have been carried out. 2D (1)H-(1)H PFG-COSY as well as (1)H-(13)C single and multiple bond correlated (2D GRASP-HSQC and GRASP-HMBC) experiments have been employed to characterize the compounds. 1D NOE experiments have been useful in understanding the structure of 1,3,5-tris(N-methylenzimidazolyl)benzene.     

Mass spectrometry and structure of ions of heterocyclic compounds activated by collision: Naphthiridines and benzazines

The dissociation and the structure at the isomeric [M — HCN]⁺ and [M — 2HCN]⁺ ions, formed during the fragmentation of naphthiridines and benzazines, were investigated by the collisionally activated dissociation (CAD) method. It was established that the stable [M — HCN]⁺ ions of 1,5- and 1,8-naphthiridines, 1,6-naphthiridine, quinoxaline, and quinazoline have different structures. The [M — 2HCN]⁺ ions can exist in two isomeric forms, one of which is characteristic of naphthiridines and the other of benzazines.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vo. 25, No. 5, pp. 626–629, September–October, 1989.     

Mass spectrometry and structures of ions of heterocyclic compounds activated by collision. 2. 2-Methylnitroindolizines

The principal pathways of the fragmentation of 2-methylnitroindolizines were investigated. The fragmentation and structures of the isomeric [M-OH]⁺ and [M-NO]⁺ ions formed in the fragmentation of these compounds were studied by the method of dissociative activation by collision (DAC). It was established that the stable [M-OH]⁺ ions formed in the fragmentation of the 1- and 3-nitro isomers as a result of the ortho effect have different structures and that their DAC spectra can be used to determine the position of the nitro group in the molecule.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1631–1635, December, 1988.     

Mass spectrometry of heterocyclic compounds. I—the behaviour of some quaternary heterocyclic iodides under electron impact

The mass spectra of five quaternary heterocyclic iodides have been investigated. The main thermal process is the anhydro base formation by HI elimination. The influence of the second heteroatom, X, on the fragmentation mode of the thermally produced anhydro bases is analysed.     

Characterization of cyclotriveratrylene inclusion compounds by means of solid state13C NMR

Solid inclusion compounds of cyclotriveratrylene (CTV) with benzene, toluene, acetone, tetrahydrofuran, acetic acid and chloroform, as well as two hydrated forms, were prepared and characterized by solid state¹³C NMR. The inclusion process for CTV appears to be quite selective, and in some instance depends critically on the presence or absence of water. A number of different structural types are indicated by the solid state¹³C NMR splitting paterns. For the guests listed above,¹H NMR in solution indicated a guest to host ratio close to 0.5, except for chloroform, for which the ratio is closer to 2.     

Stereochemistry of heterocyclic compounds

Summary The stereochemistry of the reaction of 1-alkyl-4-piperidones with phenyllithium depends not only on steric factors, but also on the character of the nitrogen-attached alkyl group. The effect of alkyl groups is associated with fixation of the direction of the dipole of the nitrogen atom, as a result of which the predominant direction of reaction becomes that for which the free electron pair of the nitrogen and the C-O bond of the enolate ion then arising occupy antiparallel directions.     

Stereochemistry of heterocyclic compounds

Summary On the basis of a number of chemical reactions, views are expressed on the possible steric structure of 1, 2, 5-trimethyl-4-ethyl-4-piperidinol isomers (I,, ), the corresponding acetylenic alcohols (II, ,), and certain piperidine derivatives obtained from them.     

Stereochemistry of heterocyclic compounds

Summary The O-acetates of the four isomers of decahydro-4-quinolinol were synthesized, and on the basis of the inability of these to undergo rearrangement into the corresponding N-acetates it was suggested that the method of O N acyl migration is inapplicable in the series of decahydro-4-quinolinol derivatives.     

Polarography of heterocyclic compounds

The literature data on the principles of the electrochemical reduction of heteroethylene and heteroparaffin compounds (pyrazoline, diazepine, diaziridine, pyran, pyridazone, aziridine, oxaziridine, and other derivatives), cyclic anhydrides, imides, and hydrazides of acids on a dropping mercury electrode are correlated. In addition, the effect of substituents attached to the heterocyclic ring on the polarographic behavior of heterocycles is analyzed.     

Competitive adsorption isotherm modelling of heterocyclic nitrogenous compounds,pyridine and quinoline,onto granular activated carbon and bagasse fly ash

In the present study, simultaneous adsorption of quinoline and pyridine onto adsorbents such as granular activated carbon (GAC) and bagasse fly ash (BFA) from pyridine–quinoline binary aqueous solution was studied at various temperatures (288–318 K). Gathered equilibrium adsorption data were further analysed using various multicomponent competitive isotherm models such as non-modified and modified competitive Langmuir isotherms, extended-Langmuir isotherm, extended-Freundlich model, Sheindorf–Rebuhn–Sheintuch (SRS) model, and non-modified and modified competitive Redlich–Peterson isotherm model. It was observed that increase in pyridine concentration decreased the total adsorption yield and the individual adsorption yield for both the quinoline and pyridine for both the adsorbents GAC and BFA at all the temperatures studied. Identical trend was observed during the equilibrium uptake of pyridine on to GAC and BFA with an increase in quinoline concentration. The extended-Freundlich model satisfactorily represented the binary adsorption equilibrium data of quinoline and pyridine onto GAC and BFA.