V. G. Kartsev

Mass-spectrometric study of the cyclization reactions of diazoketones. 8. 1-Diazo-3,4-epoxy-4-arylbutan-2-ones

An analysis of the mass spectra of 1-diazo-3,4-epoxy-4-arylbutanones has shown that the molecular ions of these compounds lose a molecule of nitrogen and that the [M — N2]+ ions formed cyclize to form hydroxyfuran structures, whose further fragmentation determines the whole picture of the dissociative ionization of the compounds investigated under electron impact. The majority of the [M — N2]+ ions have the form of the cyclic intermediate formed in the first step of the cyclization process. It cannot, however, be ruled out that a certain portion of the [M — N2]+ ions are stabilized as a result of a Wolff rearrangement and do not cyclize at all.

Mass spectrometric study of diazoketone cyclization. 7. Phthalimidoalkyl-α-diazoketones

The molecular ions of phthalimidoalkyl-α-diazoketones that form in the gas phase under electron impact split out a nitrogen molecule and rearrange by a Wolff mechanism to ketenic ions. The alternative intramolecular heterocyclization does not occur. The decomposition mechanism of [M-N2]+ions was studied. The structures of some charged fragments that form when the phthalimide nucleus decomposes were established by high resolution spectrometry,

Diazo carbonyl derivatives of heterocycles. 2. Reaction of anhydrides of pyridine- and quinolinedicarboxylic acids with diazomethane

The reaction of anhydrides of cinchomeronic, quinolinic, and acridinic acids with diazomethane was studied. The reaction pathway that they have in common is acylation of diazomethane with opening of the anhydride ring, accompanied by the formation of the corresponding diazo ketones. It is shown that the nature of the heterocyclic part of the anhydride molecule has a substantial effect on the character of the parallel reactions.

MASS-SPECTROMETRIC STUDY OF THE CYCLIZATION OF DIAZO KETONES. 5.* CYCLIZATION OF PHTHALOYL DIPEPTIDE DERIVATIVES OF DIAZOMETHANE

An analysis of the electron-impact mass spectra of phthaloyl dipeptide derivatives of diazomethane made it possible to conclude that a certain percentage of the [M — N2]+ ions have the 1,3-oxazin-5-one structure, while some of them undergo fragmentation without cyclization. The Wolff rearrangement does not occur. Alkyl substituents in the 4 position of the resulting heterocycle hinder cyclization. Under chemical-ionization conditions the [MH — N2]+ ions exist in similar forms. The cyclization process is hindered in this case by the introduction of a benzyl substituent in the chain.

Mass-spectrometric study of the cyclization of diazo ketones. 3. Cyclization of o-(p-phenylsulfamoyl)-ω-diazoacetophenones to N-(p-phenylsulfonyl) indoxyls

A comparison of the mass spectra of o-(p-phenylsulfamoyl)-ω-diazoacetophenones and N-(p-phenylsulfonyl)indoxyls makes it possible to conclude that under the conditions of electron impact and chemical ionization the molecular ions of the examined diazo ketones lose a molecule of nitrogen and under cyclization to the corresponding N-substituted derivatives of indoxyls without undergoing the Wolff rearrangement.

Mass-spectrometric study of the cyclization of diazo ketones. 1. Cyclization of 1-diazo-3-sulfonylaminopropan-2-ones to N-sulfonylazetidin-3-ones

A comparison of the mass spectra of 1-diazo-3-sulfonylaminopropan-2-ones and N-sulfonylazetidin-3-ones makes it possible to conclude that under the conditions of electron impact and chemical ionization the molecular ions of diazo ketones lose a molecule of nitrogen and undergo partial cyclization to the corresponding azetidinones without undergoing the Wolff rearrangement.