Mass-spectrometric behavior of isatin oximes

On the basis of an analysis of the mass spectra of a large series of benzo-substituted isatin oximes it is shown that their molecular ions undergo type II Beckmann rearrangment to the corresponding o-N-carboxyaminobenzonitriles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1052–1055, August, 1986.The authors thank N. A. Klyuev for his assistance in recording the high-resolution mass spectra.     

Mass-spectrometric behavior of some C-glycopyranoside acetates

Conclusions The mass-spectrometric behavior of a number of C-glycopyranoside acetates was studiedTranslated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1157–1160, May, 1976.     

Mass-spectrometric study of isomeric 5-amino-1,2,3-thiadiazoles and 5-mercapto-1,2,3-triazoles

The behavior of the isomeric 5-amino-1,2,3-thiadiazoles and 5-mercapto-1,2,3-triazoles under electron impact was studied. It was shown that mass spectrometry can serve as a rapid and reliable method for the identification of these compounds. Key factors in the assignment of a compound to one or the other class are the peaks of the [M-N₂]⁺ ions, which are more intense in the case of the thiadiazoles, and the ions determined by the decomposition of the prototropic forms of the triazoles. The compositions of the ions were determined by the high-resolution mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–689, May, 1987.     

The ion kinetic energy and mass spectra of isomeric methyl indoles

The mass spectra of the seven isomeric methylindoles were recorded and the [metastable ion]/[daughter ion] ratios for the reactions m/e 130 → m/e 103 and m/e 103 → m/e 77 have been obtained. The ratios indicate that the decomposing [M — 1] ions (m/e 130) from the 4, 5, 6 and 7 isomers are energetically similar as are the [M — 1] ions from the 2 and 3 isomers. The results observed for the m/e → 103 m/e 77 reaction showed that the decomposing m/e 103 ions from the 2, 3, 4, 5, 6 and 7 isomers all have the same energy distribution. N-Methylindole gave ratios which were similar to the 4 to 7 isomers at 70eV but different at 20 eV. The ion kinetic energy (IKE) spectra of all the isomeric methylindoles were also obtained and the results compared with the data obtained from the [metastable ion]/[daughter ion] approach. The results from the IKE spectra indicated that the energy distributions of the [M — 1] and [(M — 1) — HCN] ions from 1-methylindole and the [(M — 1) — HCN] ions from 2-methylindole could readily be distinguished from other isomers whose [metastable ion]/[daughter ion] ratios were similar. Thus by using both techniques certain ambiguities can be resolved.     

Mass-spectrometric behavior of oxidized triacylglycerols and their TMS derivatives

The mass spectrometric fragmentation of oxidized triacylglycerols of castor oil and their TMS derivatives have been studied for the first time. Three types of fragmentary ions have been detected: 1) products of the successive elimination of TMSOH; 2) ions characteristic for unoxidized triacylglycerols; and 3) products of the cleavage of C-C bonds present in the α-positions to the TMSO groups, which are characteristic for these hydroxy acid derivatives. The origin of these ions has been confirmed by measurements of elementary composition and by the analysis of MD spectra. The specific cleavage of the C-C bonds in the α-positions to the OTMS (OH) groups permits the mass-spectrometric method to be proposed for the analysis of mixtures of oxidized triacylglycerols.     

Mass-spectrometric behavior of oxidized triacylglycerols and their TMS derivatives

The mass spectrometric fragmentation of oxidized triacylglycerols of castor oil and their TMS derivatives have been studied for the first time. Three types of fragmentary ions have been detected: 1) products of the successive elimination of TMSOH; 2) ions characteristic for unoxidized triacylglycerols; and 3) products of the cleavage of C-C bonds present in the -positions to the TMSO groups, which are characteristic for these hydroxy acid derivatives. The origin of these ions has been confirmed by measurements of elementary composition and by the analysis of MD spectra. The specific cleavage of the C-C bonds in the -positions to the OTMS (OH) groups permits the mass-spectrometric method to be proposed for the analysis of mixtures of oxidized triacylglycerols.Institute of the Chemistry of Plant Substances of the UzSSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 551–558, September–October, 1986.     

Mass-spectrometric behavior of benzo-substituted dibenzo-18-crown-6 ethers

It was shown that the intensity of the peak of the molecular ion in the mass spectra of dibenzo-18-crown-6 derivatives depends to a marked extent on the electronic properties of the substituents on the benzene ring. Fragmentation of the substituents is observed after the decomposition of the polyether ring. This permits the proposition that the preferred localization of the charge in the molecular ion and the fragment ions is on the oxygen-containing part of the molecule. The analysis of the mass spectra of benzo-substituted crown ethers renders possible the determination of substituents occurring in the aromatic part of the molecule and their steric position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 783–786, June, 1986.     

Mass-spectrometric behavior of N-substituted 2-methyl-3-acetyl pyrroles

In the dissociation of N-substituted derivatives of 2-methyl-3-acetylpyrroles by the action of electron impact, the methyl group splits off from the acetyl substituent, and then the exocyclic N-C bond is ruptured due to the preferential localization of the charge on the C₍₂₎-C₍₃₎ bond in the pyrrole ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 776–778, June, 1987.     

Mass-spectrometric identification of isomeric 1-benzoyl-2-azetidinones and 2-phenyl-4,5-dihydro-1,3-oxazin-6-ones

The mass spectra of isomeric 1-benzoyl-2-azetidinones and 2-phenyl-4,5-dihydro-1,3-oxazin-6-ones were analyzed. A more stable molecular ion and high intensities of the peaks of the ions formed from the molecular ion with the loss of ketene or a substituted ketene are characteristic for the former compounds, while low stability of the molecular ion and a higher probability of the loss of one of the groupings in the 4 position are characteristic for the latter compounds. Fragmentation schemes that are confirmed by the high-resolution mass spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1627–1631, December, 1980.We sincerely thank E. Simova and C. Drey for providing us with samples of a number of the compounds.     

Mass-spectrometric behavior of 9-hydroxy-10-nitrosophenanthrene and its diaza analogs

According to mass-spectral data, 9-hydroxy-10-nitrosophenanthrene in the gas phase exists primarily in this tautomeric form rather than in the 9-oxo-10-hydroxyimino tautomeric form, while passing to its 4,5-diaza and, particularly, its 1,8-diaza analogs shifts the equilibrium sharply to favor the o-quinoid form. The character of the fragmentation of the molecular ions of the polycyclic compounds differs markedly from the fragmentation of the acyclic rearrangement product — 2-carboxy-2'-cyanobiphenyl.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1518–1521, November, 1988.     

Melting behavior and phase diagram of isomeric diisocyanates

Differential scanning calorimetry (DSC), thermogravimetry (TG), thermomicroscopy, and FTIR/thermomicroscopy have been used to study the thermal properties of two novel diisocyanates, 1,4-bis(1-isocyanato-1-methylethyl)benzene (P) and its isomer, 1,3-bis(1-isocyanato-1-methylethyl)benzene (M). Properties measured include the heat of fusion, melting point, volatility profile, and phase behavior. The variation of the melt behavior of (P)/(M) mixtures with composition has also been studied.

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Zusammenfassung Mittels DSC, TG, Thermomikroskopie und FTIR/Thermomikroskopie wurden die thermischen Eigenschaften von 1,4-Bis(1-isocyanato-1-methylethyl)benzol (P) und scines isomers 1,3-Bis(1-isocyanato-1-methylethyl)benzol (M), zweier neuartiger Diisocyanat, untersucht. Zu den ermittelten Eigenschaften gehören Schmelzwärme, Schmelzpunkt, Verdampfungsprofil und Phasenverhalten. Die Veränderung des Schmelzverhaltens von (P)/(M)-Gemischen in Abhängigkeit von der Zusammensetzung wurde ebenfalls untersucht.

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The authors wish to thank Dr. John A. Reffner and Dr. Norman B. Colthup for their technical assistance in microscopy and infrared spectroscopy.     

Mass-spectrometric behavior of 2-methyl-3-oxo-3,4-dihydroquinoxaline derivatives

The mass spectra of 20 derivatives of 2-methyl-3-oxo (thioxo)-3,4-dihydroquinoxaline, as well as 2-nitromethylquinoxaline and 2-ethoxycarbonyl-3-oxopiperazine, were recorded in order to study the possibility of detection of a ketimine-enamine equilibrium in the gas phase. It was established that the mass-spectrometric criteria for the identification of the tautomeric forms that were previously proposed for analogous structures are inapplicable in the case of the investigated compounds. The mass spectra of all of the compounds are presented, and correlated schemes for their fragmentation are given.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1118–1121, August, 1981.     

Influence of structure on electrochemical reduction of isomeric mono- and di-, nitro- or nitrosocalix[4]arenes

Monatshefte für Chemie - Chemical Monthly - A newly synthesized series of mono- and di-, nitro- or nitrosocalix[4]arenes has been investigated electrochemically. It was shown that besides the...     

Mass-spectral behavior of benzothiolactams and isomeric ω-arylalkyl isothiocyanates

The corresponding five benzothiolactams were obtained by cyclization of racemic arylalkyl isothiocyanates in polyphosphoric acid. The fragmentation of all five pairs of isomeric compounds under the influence of electron impact was investigated thoroughly.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp, 1520–1523, November, 1980.     

Mass-spectrometric behavior of polynuclear derivatives of benzo[f]quinoline

It was established on the basis of a study of the mass spectra of benzo[f]quinoline derivatives that contain a methyl group or an aromatic or heterocyclic ring in the 1 position and various quinolyl groups (2-, 4-, and 6-quinolyl) in the 3 position that the geometry of the molecule has a decisive effect on the strength of the chemical bond between the substituents and the benzoquinoline ring. The degree of coplanarity of the heterocyclic rings determines the strength of interannular conjugation and consequently the strength of the bond between the rings. For the investigated polyheterocyclic systems the coplanarity increases in the order 2-quinolyl < 6-quinolyl < 4-quinolyl. This fact in turn has a strong effect on the pathway of mass-spectrometric fragmentation for each series of derivatives, and this makes it possible to reliably distinguish the 2-, 4-, and 6-quinolyl derivatives from their mass spectra.Here and subsequently, the numbers that characterize the ion are the mass-to-charge ratios.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 520–526, April, 1979.     

Synthesis of nitro- and aminoindoles

Optimal conditions are proposed for the direct nitration of 2,3-dimethylindoles containing methyl and methoxy groups in the benzene ring. In contrast to 5- and 6-methylindoles and 5- and 6-methoxyindoles, nitration of 7-methyl-and 7-methoxy-2,3-dimethylindoles proceeds differently under the same conditions. A series of previously unreported aminoindoles was obtained by reduction of the nitroindoles.Mordova State Pedagogical Institute, 430007 Saransk, Russia; e-mail:mgpi@si.moris.ru and M. V. Lomonosov State University, 119899 Moscow, Russia, e-mail:yumar@org.chem.msu.su. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1630–1636, December, 1999.     

Synthesis of nitro- and aminoalkylphosphonates

Conclusions Some new O, O-dialkyl nitroalkylphosphonates were synthesized by the addition of dialkyl phosphites and thiophosphites to nitroolefins. The corresponding aminophosphonates were obtained from them by reduction. The hydrolysis of the latter gave the corresponding aminoalkylphosphonic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1164–1168, May, 1972.     

Mass-spectrometric behavior of some cyano-substituted 4-(β-chloroethylmercapto)-sym-triazines

Intense [M-Cl]⁺ and [M-CT₂=CCNCl]⁺ ion peaks are characteristic for the mass spectra of 4-(-chloro--cyanoethylmercapto)-sym-triazines. The introduction of monoalkylamino groups into the 2 and 6 positions of the heteroring does not lead to the development of [M-HCl]⁺ ion peaks in the mass spectra or to a change in the characteristic fragmentation pathways.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1268–1270, September, 1982.