Studies directed toward synthesis of quassinoids. VI—mass spectral fragmentation of D-ring seco esters and δ-lactone derivatives of cholic acid

1978 ◽  
Vol 13 (6) ◽  
pp. 307-314 ◽  
Author(s):  
Jerry Ray Dias ◽  
R. Ramachandra ◽  
Bahman Nassim
Keyword(s):  
Cholic Acid ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Derivatives Of

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.

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.

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