Massenspektrometrische Fragmentierung von Trimethylsilylderivaten (TMS) des Thyrotropin-„Releasing“-Hormons (TRH) und dessen Teilstrukturen / Mass Spectroscopy of Trimethylsilyl Derivatives of Thyrotropin-releasing Hormone and its Constituents

1973 ◽  
Vol 28 (11-12) ◽  
pp. 820-823 ◽  
Author(s):  
W. A. König ◽  
S. Fuchs ◽  
K. Zech ◽  
W. Voelter
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectroscopy ◽  
Peptide Hormones ◽  
Thyrotropin Releasing Hormone ◽  
Mass Spectral Fragmentation ◽  
Releasing Hormone ◽  
Mass Spectral ◽  
Trimethylsilyl Derivatives ◽  
Fragmentation Patterns ◽  
Derivatives Of

The mass spectral fragmentation patterns of trimethylsilyl derivatives of TRH and its constituents are discussed. The utility of these derivatives for the control of the synthesis of peptide hormones by mass spectrometry is obvious.

scholarly journals Synthesis and Mass Spectral Fragmentation Patterns of Brassinolide Early Biosynthetic Precursors Labeled at C-26

2013 ◽  
Vol 8 (6) ◽  
pp. 1934578X1300800
Author(s):  
Vladimir A. Khripach ◽  
Danuše Tarkowská ◽  
Vladimir N. Zhabinskii ◽  
Olga V. Gulyakevich ◽  
Yurii V. Ermolovich ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Mass Spectrometric ◽  
Keto Group ◽  
Liquid Chromatography Mass Spectrometry ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Natural Brassinosteroids ◽  
Mass Spectrometric Behavior

New analogues of brassinolide biosynthetic precursors with three deuterium atoms at non-exchangeable positions have been synthesized to be used as standards for quantification of natural brassinosteroids by liquid chromatography-mass spectrometry. [26-2H3](22 R,23 R,24 S)-22,23-Dihydroxy-6β-methoxy-24-methyl-3α,5-cyclo-5α-cholestane was used as a starting material for the preparation of campestane derivatives having a 22 R,23 R-diol functionality and either a hydroxy or keto group at C-3 and labeled at C-26. The mass spectrometric behavior of the newly synthesized compounds has been studied.

Microwave-induced rapid preparation of fluoro-derivatives of amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine for GC-MS confirmation assays

1994 ◽  
Vol 40 (9) ◽  
pp. 1703-1706 ◽  
Author(s):  
W C Thompson ◽  
A Dasgupta
Keyword(s):  
Microwave Irradiation ◽  
Conventional Technique ◽  
Conventional Heating ◽  
Chromatographic Retention ◽  
Rapid Preparation ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Derivatives Of ◽  
Fluoro Derivatives

Abstract We prepared trifluoroacetyl, pentafluoropropyl, and heptafluorobutyl derivatives of amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA) in 45 s, 1 min, and 6 min, respectively, by using microwave irradiation. Conventional techniques require heating the reaction mixture for 15 min at 40 degrees C for trifluoroacetyl derivatives, 15 min at 75 degrees C for pentafluoropropyl derivatives, and 40 min at 60 degrees C for heptafluorobutyl derivatives. The mass-spectral fragmentation patterns and the gas-chromatographic retention times of the derivatives obtained by both microwave irradiation and conventional heating were similar. Perfluorooctanoyl derivatives of amphetamine can be prepared quantitatively by either heating the reaction mixture for 30 min at 60 degrees C or by 1 min of microwave irradiation. Conversion of methamphetamine and MDMA to the corresponding perfluorooctanoyl derivatives was not quantitative by either technique, although the yield of the derivative in the conventional technique was much higher.

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
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