Amaryllidaceae and Sceletium alkaloids

A great number of natural products, especially alkaloids, which exhibit a range of biological activities including acetylcholinesterase inhibition and antineoplastic, cardiovascular and immunostimulatory activities, have been isolated from the plants of the Amaryllidaceae family. this review summarizes isolation, biological activity, and synthetic studies of these alkaloids. The primary biosynthetic pathways of each type of alkaloids are also proposed.     

Amaryllidaceae and Sceletium alkaloids

Structurally diverse alkaloids, which show significant biological activities, are abundant in the plants of the family Amaryllidaceae. The latest progress on the isolation, identification, biological activity, and chemical synthesis of Amaryllidaceae alkaloids and the structurally close Sceletium alkaloids is summarized in this review.     

Amaryllidaceae and Sceletium alkaloids

This review covers the morphology, isolation, total synthesis and biological activity of the naturally occurring alkaloids isolated from the Amaryllidaceae family, as well as the structurally related Sceletium alkaloids.     

Amaryllidaceae and Sceletium alkaloids

This review covers the isolation, biological activity and chemical synthesis of Amaryllidaceae alkaloids and the structurally related Sceletium alkaloids. The literature from July 2001 to the end of 2002 is reviewed, and 61 references are cited.     

Mass spectra of N-oxides of pyrrolizidine alkaloids

Summary The mass spectra of the N-oxides of pyrrolizidine alkaloids show three main types of ions formed as the result of the detachment of the oxygen of the NO group, dehydration with subsequent dehydrogenation, and isomerization of the nucleus. In a number of spectra the proportion of ions formed by the localization of the charge in the side chain increases.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 620–626, September–October, 1974.     

Mass spectra of the alkaloids ofDipthychocarpus strictus

The mass spectra of diptocarpaine, diptocarpamine, diptocarpiline, and diptocarpidine, isolated fromDipthychocarpus strictus, have been studied. These compounds have proved to be derivatives of alkylureas, the substituents in them being mainly methylthio-n-hexyl and methylsulfinyl-n-hexyl radicals and the products of their chemical transformation. It has been established that mass-spectrometric fragmentation of these compounds takes place with the formation of heterocyclic ions.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 365–370, May–June, 1980.     

Mass spectra of methines of the benzylisoquinoline alkaloids

Mass spectra of the stilbene type methines of the benzylisoquinoline alkaloids exhibit high melecular peaks and show structurally characteristic fragmentation patterns.     

Mass spectra of alkaloids of the type of songorine

Conclusions Aconitine, songorine, and songoramine have been isolated fromAconitum karakolicum. The structure of songoramine has been established on the basis of chemical and spectral characteristics. A scheme for the fragmentation of songorine and its derivatives has been proposed.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 101–107, 1970     

Mass spectra of alkaloids of the type of songorine

Chemistry of Natural Compounds - Aconitine, songorine, and songoramine have been isolated fromAconitum karakolicum. The structure of songoramine has been established on the basis of chemical and...     

Mass spectra of diterpene alkaloids with the hetisine skeleton

An analysis of literature material has shown that the stability of the M⁺ ions of bases with the hetisine skeleton decreases considerably when an OR group is present at C-1, C-6, or C-9. The directions of fragmentation are not monotypical and depend greatly on the positions of the oxygen substituents. A similar conclusion can be made from a study of the group and individual features of the breakdown of hetisine, nominine, talatisine, and their derivatives revealed with the aid of high-resolution mass spectrometry and MD spectra. An unusual property of these spectra is the formation of nitrogen-free fragments. The mass spectra of hetisine alkaloids of a new type — zeraconine and its N-oxide — have been characterized.     

Mass spectra of diterpene alkaloids with the hetisine skeleton

An analysis of literature material has shown that the stability of the M⁺ ions of bases with the hetisine skeleton decreases considerably when an OR group is present at C-1, C-6, or C-9. The directions of fragmentation are not monotypical and depend greatly on the positions of the oxygen substituents. A similar conclusion can be made from a study of the group and individual features of the breakdown of hetisine, nominine, talatisine, and their derivatives revealed with the aid of high-resolution mass spectrometry and MD spectra. An unusual property of these spectra is the formation of nitrogen-free fragments. The mass spectra of hetisine alkaloids of a new type — zeraconine and its N-oxide — have been characterized.Institute of the Chemistry of Plant Substances of the Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 542–553, July–August, 1987.     

Mass spectra and stereochemistry of some macrocyclic pyrrolizidine alkaloids

Conclusions On the basis of the results of a comparison of the mass spectra of macrocyclic pyrrolizidine alkaloids with a known configuration of the side chain (trichodesmine, monocrotaline) with the spectra of incanine, crispatine, and fulvine a hypothesis has been put forward on the relative positions of the substituents at C₂ and C₃ in the molecules of the three latter compounds.Order of the Red Banner of Labor Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 40–44, January–February, 1974.     

Mass spectra of dihydro derivatives of alkaloids of the lycorine type

Conclusions The mass spectra of dihydrolycorine, diacetylidhydrolycorine, dihydroungminorine, diacetyldihydroungminorine, and diacetyldihydroungminorinone have been studied.The fragmentation of these compounds differs from that of alkaloids of the lycorine type only by the absence of a retrodiene type of decomposition.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 4, pp. 227–230, 1968