Alkaloids from Buxus sempervirens L. III. Mass spectral fragmentation

1965 ◽  
Vol 30 (8) ◽  
pp. 2869-2874 ◽  
Author(s):  
L. Dolejš ◽  
V. Hanuš ◽  
Z. Votický ◽  
J. Tomko
Keyword(s):  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Buxus Sempervirens

scholarly journals The Alkaloid-Enriched Fraction of Pachysandra terminalis (Buxaceae) Shows Prominent Activity against Trypanosoma brucei rhodesiense

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 591
Author(s):  
Dagmar Flittner ◽  
Marcel Kaiser ◽  
Pascal Mäser ◽  
Norberto P. Lopes ◽  
Thomas J. Schmidt
Keyword(s):  
Trypanosoma Brucei ◽  
Trypanosoma Brucei Rhodesiense ◽  
Acid Base ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Regression Modelling ◽  
Aerial Parts ◽  
Buxus Sempervirens ◽  
Alkaloid Fraction

In the course of our studies on antiprotozoal natural products and following our recent discovery that certain aminosteroids and aminocycloartanoid compounds from Holarrhena africana A. DC. (Apocynaceae) and Buxus sempervirens L. (Buxaceae), respectively, are strong and selective antitrypanosomal agents, we have extended these studies to another plant, related to the latter—namely, Pachysandra terminalis Sieb. and Zucc. (Buxaceae). This species is known to contain aminosteroids similar to those of Holarrhena and structurally related to the aminocycloartanoids of Buxus. The dicholoromethane extract obtained from aerial parts of P. terminalis and, in particular, its alkaloid fraction obtained by acid–base partitioning showed prominent activity against Trypanosoma brucei rhodesiense (Tbr). Activity-guided fractionation along with extended UHPLC-(+)ESI QTOF MS analyses coupled with partial least squares (PLS) regression modelling relating the analytical profiles of various fractions with their bioactivity against Tbr highlighted eighteen constituents likely responsible for the antitrypanosomal activity. Detailed analysis of their (+)ESI mass spectral fragmentation allowed identification of four known constituents of P. terminalis as well as structural characterization of ten further amino-/amidosteroids not previously reported from this plant.

Triazolopyridine nucleosides. II. Glycosylations of 3-oxo-s-triazolo[4,3-a]pyridines with accompanying conversions into 2-oxo-s-triazolo[1,5-a]pyridine nucleosides

1977 ◽  
Vol 55 (5) ◽  
pp. 831-840 ◽  
Author(s):  
Brian Maurice Lynch ◽  
Suresh Chandra Sharma
Keyword(s):  
General Structure ◽  
Spectroscopic Properties ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
H Nmr ◽  
Pyridine Nitrogen ◽  
Methyl Derivatives ◽  
Fragmentation Patterns ◽  
Ribose Moiety ◽  
C Nmr

3-Oxo-s-triazolo[4,3-a]pyridine and various C-methyl derivatives (general structure 1) have been converted into the 2-β-D-ribofuranosyl species 2 and thence 4 via Friedel–Crafts catalyzed reaction with tetra-O-acetyl-β-D-ribofuranose, followed by deblocking. During the course of these reactions, rearrangements into the isomeric 3-β-D-ribofuranosyl-2-oxo-s-triazolo[1,5-a]-pyridines occur through ring-opening of the pyridine rings yielding species 3 and 5. The proportion of rearrangement products is dependent upon the position and number of the C-methyl substituents.Structural assignments for these compounds are based upon comparisons of spectroscopic properties (1H nmr, 13C nmr, uv) with model compounds from each isomeric series; structural assignments for these models are based on unequivocal mass-spectral fragmentation patterns. Unlike related triazolopyridine nucleosides with the ribose moiety attached to a pyridine nitrogen (Lynch and Sharma (1976)), there are no unusual aspects in the conformations of the nueleosides of types 4 and 5.

Mass Spectra of β-Keto Esters

1972 ◽  
Vol 50 (16) ◽  
pp. 2707-2710 ◽  
Author(s):  
Larry Weiler
Keyword(s):  
Mass Spectra ◽  
Carbonyl Groups ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Keto Esters ◽  
Fragmentation Patterns

The mass spectra of several γ-substituted β-keto esters have been recorded and interpreted. The fragmentation patterns are compared to those of α-substituted β-keto esters and are found to be very useful in differentiating the α- and γ-substituted isomers. The mass spectral fragmentation schemes are dominated by cleavages α to the carbonyl groups and by McLafferty rearrangements.

Mass spectral fragmentation patterns of some 2-methyl-3-furancarboxanilides and 2-methyl-3-furancarbothioanilides. II

1995 ◽  
Vol 9 (9) ◽  
pp. 778-780 ◽  
Author(s):  
Grace Karminski-Zamola ◽  
Lelja Fi??er-Jakić ◽  
Miroslav Bajić And ◽  
David W. Boykin
Keyword(s):  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Fragmentation Patterns

scholarly journals On the Mass Spectral Fragmentation of 2,5-Diphenyl-p-benzoquinones.

1973 ◽  
Vol 27 ◽  
pp. 3427-3434 ◽  
Author(s):  
Mauri Lounasmaa ◽  
Arto Karjalainen ◽  
Lennart Kenne ◽  
Åke Pilotti ◽  
Sigfrid Svensson ◽  
...  
Keyword(s):  
Mass Spectral Fragmentation ◽  
Mass Spectral

scholarly journals Phytochemical investigation of seeds of Trachyspermum ammi Linn. by GC-MS

2017 ◽  
Vol 3 (2) ◽  
pp. 91-100 ◽  
Author(s):  
Ekta Sharma ◽  
B S Arora
Keyword(s):  
Human Cancer ◽  
Standard Procedure ◽  
Retention Indices ◽  
Gas Chromatography Mass Spectrometry ◽  
Mass Spectral Fragmentation ◽  
Human Cancer Cell Lines ◽  
Mass Spectral ◽  
Phytochemical Investigation ◽  
Trachyspermum Ammi ◽  
Mature Seeds

The present study embraces phytochemical investigation of the essential oil extracted from the mature seeds of Trachyspermum ammi Linn for different constituents by subjecting the oil to gas chromatography-mass spectrometry (GC-MS) analysis. The identification of the constituents is based upon retention indices and by comparison of their mass spectral fragmentation patterns against the commercial library mass spectra (Wiley, Nist etc.). Ellagic acid (EA), which is a natural phenol antioxidant, has been isolated from methanol extract from the mature seeds of Trachyspermum ammi Linn. Also, Thymol (Thl), a naturally occurring phenolic compound, has been crystallized by the reported standard procedure from oil extracted from these mature seeds. Both these compounds have been evaluated for their possible anti-cancer effect against a selected panel of human cancer cell lines by means of sulforhodamine B assay.

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