The configuration of badrakemin and gummosin,and the identity of isobadrakemin,colladonin, and farnesiferol A

Conclusions The structure of pegamine has been established from its UV, IR, NMR, and mass spectra.2. A fragmentation scheme for pegamine on mass spectrometry has been proposed.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 4, pp. 453–455, 1970     

The structure of arnifolin

Summary Structure (I) is proposed for arnifolin — a sesquiterpene lactone fromArnica foliosa Nutt. andArnica montana L.All-Union Scientific-Research Institute for Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 270–272, May–June, 1971.     

Mass-spectrometric and quantum-chemical study of fragmentation of diallyl esters of dicarboxylic acids

In a mechanistic study of thermal breakdown of diallyl polymers, six diallyl esters of dicarboxylic acids have been investigated by means of mass spectrometry. A characteristic feature of the fragmentation of these compounds is the low stability of the molecular ions and detachment of the allyl cation, the peak of which is usually the highest in the mass spectrum. In interpreting such an unusual path of fragmentation of esters, quantum-chemical calculations have been carried out in the MINDO/3 approximation; the preferred conformation of the diallyl maleate molecule and the distribution of electron density in this conformation have been determined, and the most stable cyclic structure of the intermediate cation [CH=CH(CO)₂OH]⁺ has been established. The nature of the bridge between the carboxyl groups in diallyl esters of dicarboxylic acids has practically no influence on the direction of fragmentation. The decisive factor in the fragmentation is the electrostatic interaction of charges on the atoms of carbonyl carbon and ester oxygen of the second carboxyl group. A fragmentation scheme with the formation of intermediate cyclic cations is proposed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 3, pp. 300–307, May–June, 1990.     

A mass spectrometric study of some triterpenes of the dammarane series

Summary 1. The mass spectra of tetracyclic triterpenes of the dammarane series with substituents at C-3, 6, and 12 and with side chains of various structures have been studied.2. The main direction of fragmentation is the formation of ions as the result of the decomposition of the side chain and of ring C, the second type of fragmentation being controlled by the structure of the side chain.Institute of Biologically Active Substances of the Far-Eastern Scientific Center of the Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 286–294, May–June, 1971.     

V. Mass spectrometry of the alkaloids ofArundo donax

The mass spectra of alkaloids isolated from the epigeal part of the plant Arundo donax L. have been investigated. The main pathways of fragmentation under electron impact have been determined for arundine, ardine, donaxaridine, donaxarine, and donaxinine. An analogy has been found in the fragmentation of the M⁺ ions of donaxarine and donaxinine, the main pathway of their fragmentation consisting in the elimination of the elements of the N-methylpyrrolidone ring.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 217–220, March–April, 1996. Original article submitted September 25, 1995.     

Mass spectrometry of sesquiterpenoids of the carotane series. Influence of various methods of ionization on the fragmentation of sesquiterpenols

The mass spectra of five natural sesquiterpenols with various methods of ionization have been studied. A distinct direction of breakdown according to the alternative positions of the OH group at the C-4 or C-5 atom for the skeleton has been found. It has been established that the use of chemical ionization and of secondary-ion mass spectrometry raises the intensity of the molecular ions and increases specific directions of fragmentation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 522–525, July–August, 1993.     

A glucuronosyldiglyceride from an actinomycete

Summary 1. From the sum of the cell lipids of a strain ofStreptomyces producing the antibiotic aureolic acid a glycoside has been isolated which is a 1-O-(-D-glucopyranuronosyl)-2,3-diacylglycerol.2. The trimethylsilyl derivatives of glycerol glycosides have been studied by mass spectrometry. Features of the fragmentation under electron impact of the trimethylsilyl derivatives of the glyceryl glucosides have been determined; the results obtained enable the method of combined gas-liquid chromatography and mass spectrometry to be used for the identification of diacylglyceryl uronosides in lipid fractions.M. M. Shemyakin Institute of the Chemistry of Natural Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 704–715, November–December, 1973.     

Mass spectrometric study of apogalanthamine and its derivatives

Conclusions 1. The mass spectra of apogalanthamine, its monomethyl ether, and the acetate of the monomethyl ether have been studied.2. The general nature of the fragmentation of these compounds and of alkaloids of the galanthamine type has been shown and specific features of fragmentation due to the presence of the second aromatic ring have been determined.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 519–521, 1969     

Mass-Spectrometric analysis of homoaporphine bases structure of szovitsinine

Summary The mass spectra of homoaporphine bases have been studied. The main decomposition of these bases is connected with the elimination of the substituent in position C₃.The mass spectrum of the new base szovitsinine has been studied and the structure of 2,4-dihydroxy-3,5,6-trimethoxyhomoaporphine has been proposed as the most probable form of it.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 230–234, March–April, 1977.     

Characteristics of the mass spectra of ecdysteroids with different numbers of -OR groups

The mass spectra of 15 phytoecdysteroids and acetyl derivatives have been compared. With a decrease in the number of -OR groups, the contribution of cleavages of the bonds of the steroid skeleton increases. 20,22-Diols are characterized by the greatest significance of fragmentation at the C-20–C-22 bond. In all the spectra, clear indications of fragmentation of the side chain at the C-22–C-23, C-23–C-24, and C-24–C-25 bonds are observed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 518–528, July–August, 1980.     

Mass and NMR spectra of haplophyllidine and perforine and of their derivatives

Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C₈ and C₄.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969     

A mass-spectroscopic study of the terpenoid coumarins mogoltadone,gummosin, and farnesiferol A

Summary The mass spectra of the terpenoid coumarins mogoltadone (I), gummosin (II), and farnesiferol A (III) and their deuterium analogs (IV–VI) have been studied. It has been shown that the main and auxiliary directions of the decomposition of the molecular ions of the substances are similar to the dissociative ionization of the terpenoid coumarins studied previously. The fragmentation of the ions corresponding to the terpene residues of these compounds permits the determination of the presence of keto and hydroxy groups in the bicyclic terpene system and provides the possibility of distinguishing the stereoisomers (II) and (III) with different orientations of the hydroxy groups and also of determining the presence in the terpene residue of a gem-dimethyl grouping in the vicinal position to the keto or hydroxy group.M. V. Lomonosov Moscow State University. Patrice Lumumba International Friendship University. Moscow Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 207–212, March–April, 1977.     

Mass spectrometric study of ring-chain tautomers of 3-amino(hydroxy)pyrazolidines

The mass spectrometric fragmentation of substituted 3-amino-, 3-hydrazino-, and 3-hydroxypyrazolidines has been studied. In the gas phase these compounds exist partly as the acyclic tautomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1334–1338, 1986.     

An investigation by the NMR method of the structure of the alkaloid sophorine fromSophora alopecuroides

A new base — sophorine, with mp 59–60°C, [] _D ²³ -18.9° (c 0.98; ethanol) — has been isolated from the epigeal part of the plantSophora alopecuroides L. Its IR spectrum and the nature of its mass spectrometric composition have permitted sophorine to be assigned to the quinolizidine alkaloids. The¹³C NMR spectrum has shown the presence of 19 carbon atoms. The analysis of several of the carbon signals has confirmed the results of IR and mass spectroscopy. Additional details of the structure of sophorine have been obtained from its PMR spectrum.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 604–608, September–October, 1981.     

Mass-spectrometric study of some derivatives of furo- and dihydrofurocoumarins

Summary The mass spectra of eight compounds beloning to the class of linear furo- and dihydrofurocoumarins have been studied. A scheme of the fragmentation of these substances under the action of electron impact has been proposed. It has been shown that the mass-spectrometric method permits acyl derivatives of oreoselone to be distinguished reliably from acyl derivatives of dihydrooreoselol and the latter series of substances from derivatives isomeric with them belonging to the class of dihydrofuro- and dihydropyranocoumarins.M. V. Lomonsov Moscow State University. All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 560–568, September–October, 1974.     

Mass spectra of 3-arylidene-1H-2,3-dihydro-1,4-benzodiazepin-2-ones

The scheme of the fragmentation of arylidene derivatives of 5-phenyl-1,4-benzodiazepin-2-ones was established by means of high-resolution mass spectrometry. One of the principal fragmentation pathways of these compounds is cleavage of the 2C-3C and 4N-5C bonds to give two fragments. Depending on the substituents in the arylidene portion of the molecule, the charge is localized primarily on one or the other of these fragments. The mechanism of the formation of the [ArCH₂]⁺ ions observed in the mass spectra of all of the investigated compounds was established on the basis of the mass spectrum of the 1N-deuterium-labeled compound. The specific fragmentation pathways due to the ortho effect of the nitro group are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1690–1696, December, 1976.     

Mass spectrum of glycosides of ecdysteroids and their peracetates

Features of the fragmentation of the carbohydrate chains of galactopyranosides of ecdysteroids (sileneosides A–D) and their peracetates under electron impact are discussed. The migration of Gal and AcGal residues from C-22 to C-20 has been detected. The secondary-ion mass spectra of the sileneosides using liquid matrices are considered.Institute of Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. All-Union Scientific-Research Institute of Agricultural Biotechnology, V. I. Lenin All-Union Academy of Agricultural Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 226–231, March–April, 1991.     

A mass-spectrometric investigation of derivatives of Δ3-dihydropyrane

Conclusions The mass spectra of eleven derivatives of ³-dihydropyrane have been recorded and their basic fragmentation paths have been studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1184–1187, May, 1970.     

Characterisation of selected drugs with nitrogen-containing saturated ring structures by use of electrospray ionisation with ion-trap mass spectrometry

The electrospray ionisation–ion-trap mass spectrometry (ESI–MS ⁿ ) of selected drugs with nitrogen-containing saturated ring structures has been investigated. Sequential product-ion fragmentation experiments (MS ⁿ ) have been performed to elucidate degradation pathways for the [M+H]⁺ ions and their predominant fragment ions. These MS ⁿ experiments result in characteristic fragmentations in which functional groups are generally cleaved from the ring systems as neutral molecules such as H₂O, amines, alkenes, esters, carboxylic acids, etc. When such a nitrogen-containing drug molecule also contains a functional group, such as an ester, that on liberation as a neutral molecule has a significantly lower –H _f° value than that of the corresponding amine then the former is preferentially liberated. Furthermore, when an aromatic entity is present in these drug molecules together with the nitrogen-containing saturated ring structure fragmentation of the latter ring occurs with the former, predictably, being resistant to fragmentation. The structures of fragment ions proposed for ESI–MS ⁿ can be supported by electrospray ionisation–quadrupole time-of-flight mass spectrometry (ESI–QTOFMS). The data presented in this paper therefore provide useful information on the structure of these heterocyclic compounds which could be used to characterise unknown drug compounds isolated from natural sources, for example.     

Mass spectra of functional derivatives of sterically hindered olefins

Conclusions Study has been made of the mass spectra of certain functionally substituted sterically hindered phenols. It has been found that the presence of functional groups in the aromatic ring p-position generally has no effect on the fragmentation pattern. More complex substituents (-COR, -COOR, -CH₂Hal, -CH₂CH₂Hal, etc.) can be involved in the fragmentation process.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2686–2693, December, 1976.