A. S. Moskovkin

Heteroadamantanes and their derivatives

Abstract9-Amino-3,6-diazahomoadamantanes were prepared from 3,6-diazahomo-adamantan-9-ones through oximes and converted into 9-acetylamino-3,6-diaza-homoadamantanes with acetic anhydride. It was shown that oximes with one substituent in the nodal position are formed as one geometric isomer with the E-position of the hydroxyl group relative to the substituent.

Investigation of the ring-chain tautomerism of alkyl-substituted 6-hydroxytetrahydro-1,3-thiazine-2-thiones by IR spectroscopy and mass spectrometry

The ring-chain tautomerism of alkyl-substituted 6-hydroxytetrahydro-1,3-thiazine-2-thiones was studied by IR spectroscopy and mass spectrometry. The dependence of the tautomeric equilibrium on the number and location of the methyl groups in the molecule and the aggregate state of the substance was ascertained. Substituted 3,4-dihydro-2H-1,3-thiazine-2-thiones were obtained by the dehydration of the 6-hydroxytetrahydro-1,3-thiazine-2-thiones

Heteroadamantanes and their derivatives 11. Synthesis of 3,6-diazahomoadamantan-9-one and its derivatives with substituents in the angular positions

The condensation of ketones with tetramethylenediethylenediamine led to the isolation of 3,6-diazahomoadamantan-9-one and its derivatives with substituents in the angular positions; their structure was confirmed by the data of the IR, PMR, and mass spectra.

Heteroadamantanes and their derivatives. 17. Wolff—Kishner reduction of 3,6-diazahomoadamantan-9-ones

Wolff—Kishner reduction of the keto group of 3,6-diazahomoadamantan-9-ones to a methylene group was investigated. It was shown that diazahomoadamantanones yield hydrazones in the reaction with hydrazine hydrate, and they are converted into 3,6-diazahomoadamantane derivatives with one or two substituents in nodal positions when heated with a base. Unsubstituted 3,6-diazahomoadamantane is not formed in these conditions, since 3,6-diazahomoadamantan-9-one hydrazone is convened into azine when heated above 70‡C. Other hydrazones are also converted into azines when heated, but at a higher temperature —above 150‡C.

Heteroadamantanes and their derivatives. 14. Synthesis of 3,6-diazahomoadamantan-9-ols and their acetates

The reduction of 3,6-diazahomoadamantan-9-ones with metal hydrides gave 3,6-diazahomoadamantan-9-ols, which were convened to acetates by the action of acetic anhydride. The effect of the substituents in the nodal positions on the rates of reduction and acylation is demonstrated.

Synthesis and mass spectra of 4-mono- and 4,4-disubstituted 5,6-tetramethylenetetrahydro-1,3-oxazine-2-thiones

The syntheses and mass spectra of 5,6-tetramethylenetetrahydro-1,3-oxazine-2-thione and its 4-mono- and 4,4-disubstituted analogs are reported. The primary decay processes under electron impact are loss of the 1,3-oxazine ring, formation of hydrocarbon ions, and rearrangement of the [M−C6H9]+ ion.

Heteroadamantanes and their derivatives. 7. Synthesis and mass-spectrometric study of functional derivatives of 5-mono- and 5,7-disubstituted 1,3-diazaadamantanes

The chemical behavior of the carbonyl group of 5-mono and 5,7-disubstituted 6-oxo-1,3-diazaadamantanes was studied. The structures of the functional derivatives obtained were confirmed by IR and 1H and 13C NMR spectral data. The behavior of the compounds under the influence of electron impact was studied, and the principal pathways of fragmentation of their molecules were ascertained.

Mass-spectrometric study of the products of intramolecular cyclization of 1,3-amido alcohols. 5-6-Dihydro-4H-1,3-oxazines and 2-oxazolines

The mass spectra of substituted 5,6-dihydro-4H-1,3-oxazines and 2-oxazolines were studied for the identification of the products of intramolecular cyclization of 1,3-amido alcohols. The fragmentation of the molecular ions of 1,3-oxazines under the influence of electron impact proceeds via both fragmentation of the retrodiene type and with the formation of rearrangement ions, the relative intensities of the peaks of which are determined by the nature and position of the substituents in the heteroring. The molecular ions of 2-oxazolines undergo fragmentation chiefly with the loss of a molecule of a ketone.

Mass-spectrometric study of ring-chain tautomerism in a series of substituted 4-hydroxyhexahydropyrimidine-2-thiones

In order to investigate the ring-chain tautomerism of substituted 4-hydroxyhexahydropyrimidine-2-thiones the mass spectra of a series of compounds of this group were studied. It is shown that equilibrium exists between the cyclic hydroxy form and the acyclic oxo form, which belongs to the oxoalkylthiourea class, in a series of 3-alkyl(aryl)-4,6,6-trimethyl derivatives in the gas phase. The mass spectra of these compounds contain intense peaks of [M-18]+ and [M-33]+ ions, which are formed as a result of the successive elimination of a water molecule and a methyl radical by the molecular ions. The fragmentation of 3-alkyl-4,5-dimethyl derivatives takes place from the open oxo form of the molecular ion with detachment of the terminal groups.