scholarly journals Isolation and identification of products from alkylation of nucleic acids: ethyl- and isopropyl-purines

1975 ◽  
Vol 145 (1) ◽  
pp. 73-84 ◽  
Author(s):  
P D Lawley ◽  
D J Orr ◽  
M Jarman
Keyword(s):  
Mass Spectrometry ◽  
Nucleic Acids ◽  
Formic Acid ◽  
Absorption Spectra ◽  
Alkaline Solution ◽  
Alkylating Agents ◽  
Methyl Ethyl ◽  
Neutral Solution ◽  
Isolation And Identification ◽  
Methylating Agents

Ethylation and isopropylation of guanine in alkaline solution, or of adenine in formic acid, by alkyl methanesulphonates gave the following products: 1-, N2-, 3-, O6-, 7- and 9-alkylguanines; 1-, 3-, 7- and 9-alkyladenines. The products were identified from their characteristic u.v-absorption spectra, by comparison with either known ethyladenines or with the corresponding known methyladenines, and were also characterized by mass spectrometry. Their chromatographic properties on paper, t.l.c. and various columns were determined. DNA was alkylated in neutral solution with 14C-labelled alkyl methanesulphonates and the ratios of the alkylpurines formed were obtained, and compared for alkylation by methyl, ethyl and isopropyl methanesulphonates and by N-methyl-N-nitrosourea. The extents of alkylation at O-6 of guanine relative to those at N-7 of guanine varied with the reactivity of the methylating agents according to the predictions of Swain & Scott (1953) relating nucleophilicity of the groups alkylated with the substrate constants of the alkylating agents. The relative extents of alkylation at N-3 of adenine did not follow this correlation.

SYNTHESES AND ABSORPTION SPECTRA OF 2-SUBSTITUTED-3-HYDROXY-5-PYRAZOLONES: 4-n-HEXYL-5-PYRAZOLONES-4-C14

1954 ◽  
Vol 32 (9) ◽  
pp. 823-838 ◽  
Author(s):  
Paul E. Gagnon ◽  
Jean L. Boivin ◽  
Roderick MacDonald ◽  
Leo Yaffe
Keyword(s):  
Absorption Spectra ◽  
Infrared Spectra ◽  
Alkaline Solution ◽  
Diethyl Malonate ◽  
Ultraviolet Absorption ◽  
Methyl Ethyl ◽  
Specific Activities

2-Monosubstituted-3-hydroxy-5-pyrazolones were prepared from diethyl malonate itself and diethyl malonates monosubstituted with methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, and benzyl groups by condensation of the esters with o-, m-, and p-chlorophenylhydrazines, and n-hexylhydrazine. By using diethyl n-hexyl malonate-2-C14 and o-, m-, and p-chlorophenylhydrazines, and n-hexylhydrazine as starting materials the corresponding pyrazolones labelled with C14 were obtained. Their specific activities were 7.0, 8.8, 9.0, and 8.8 µc./gm. respectively. Ultraviolet absorption spectra were determined in neutral and alkaline solution and the infrared spectra were also obtained. From the data it was possible to ascribe the tautomeric structures best suited for the compounds.

scholarly journals A HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY METHOD DEVELOPMENT FOR THE QUANTITATIVE DETERMINATION OF ENALAPRIL MALEATE FROM CACO-2 CELL MONOLAYERS

2018 ◽  
Vol 11 (7) ◽  
pp. 89
Author(s):  
Liliya Logoyda
Keyword(s):  
Mass Spectrometry ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Formic Acid ◽  
High Performance ◽  
Liquid Chromatography Mass Spectrometry ◽  
Enalapril Maleate ◽  
Cell Monolayers ◽  
Chromatography Mass Spectrometry

Objective: A simple, rapid high-performance liquid chromatography-mass spectrometry (HPLC MS/MS) method was developed for the determination of enalapril maleate from confluent Caco-2 monolayers and aqueous solution.Methods: Chromatography was achieved on Discovery C18, 50×2.1 mm, 5 μm column. Samples were chromatographed in a gradient mode (eluent A [acetonitrile-water-formic acid, 5: 95:0.1 v/v] and eluent B [acetonitrile-formic acid, 100:0.1 v/v]). The initial content of the eluent B is 0%, which increases linearly by 1.0 min to 100% and 1.01 min returns to the initial 0%. The mobile phase was delivered at a flow rate of 0.4 ml/min into the mass spectrometer ESI chamber. The sample volume was 5 μl.Results: Under these conditions, enalapril maleate was eluted at 1.52 min. According to the Caco-2 test results, enalapril showed low permeability. It should be noted that the recovery value for enalapril is 100.62 %. Low in vitro permeability data for enalapril are in good agreement with the literature data.Conclusion: From results of the analysis, it can be concluded that developed method is simple and rapid for determination of enalapril maleate from confluent Caco-2 monolayers and aqueous solution. Acquired results demonstrate that proposed strategy can be effortlessly and advantageously applied for examination of enalapril from Caco-2 cell monolayers.

Determination and Identification of Daminozide in Fresh Fruits Purchased in Japan

1990 ◽  
Vol 53 (8) ◽  
pp. 689-692
Author(s):  
YUMIKO NAKAMURA ◽  
YUKARI HASEGAWA ◽  
YASUHIDE TONOGAI ◽  
YOSHIO ITO
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Alkaline Solution ◽  
Colorimetric Method ◽  
Gas Chromatography Mass Spectrometry ◽  
Unsymmetrical Dimethylhydrazine ◽  
Chromatography Mass Spectrometry ◽  
Trade Name ◽  
Red Color

The concentration of residual daminozide (trade name of formulation: Alar or B-Nine) in cherries, grapes, peaches, and apples purchased in Japan was investigated using the colorimetric method. Daminozide hydrolyzes in boiling strong alkaline solution to release unsymmetrical dimethylhydrazine which is distilled and reacted with trisodium pentacyanoamine ferroate to form a specific red color at pH 4.5. This color is measured spectrophotometrically. The levels of daminozide detected were 0.07–1.39 ppm in cherries (11 samples), 0–0.36 ppm in grapes (10 samples), 0–0.42 ppm in peaches (9 samples), and 0–0.88 ppm in apples (10 samples). Furthermore, daminozide in each sample was identified as methyl daminozide by the gas chromatography/mass spectrometry (GC/MS) method.

Electron attachment in irradiated solutions

1964 ◽  
Vol 277 (1371) ◽  
pp. 549-561 ◽  
Keyword(s):  
Absorption Spectra ◽  
Transient Absorption ◽  
Electron Attachment ◽  
Alkaline Solutions ◽  
Neutral Solution ◽  
Anaerobic Conditions ◽  
Ketyl Radical ◽  
Neutral Radical ◽  
Transient Absorption Spectra ◽  
Flash Spectroscopy

Transient absorption spectra have been obtained by pulsed radiolysis and flash spectroscopy of neutral and alkaline solutions of benzophenone under anaerobic conditions. These spectra demonstrate the formation of the ketyl radical ion (C 6 H 5 ) 2 Ċ—O - as a primary product resulting from electron attachment to benzophenone. In neutral solution, the rapid neutralization of the ketyl ion produces the neutral radical (C 6 H 5 ) 2 Ċ—OH, and this is shown by a change in the optical absorption spectrum. Neither of the absorption spectra due to these species is observed in acid solutions. These observations show that in neutral and alkaline solution, the hydrated electron reacts directly with the solute, whereas in acid solution it is converted to the hydrogen atom before reacting with the solute.

Isolierung und Identifizierung von Sterinen im Metabolismus des Pilzes Botrytis cinerea / Isolation and identification of sterols in the metabolism of the fungus botrytis cinerea

1983 ◽  
Vol 38 (3-4) ◽  
pp. 207-211 ◽  
Author(s):  
Peter Flesch ◽  
Lutz Gwinner ◽  
Sylvia Müller ◽  
Peter Simon
Keyword(s):  
Mass Spectrometry ◽  
Botrytis Cinerea ◽  
Analytical Methods ◽  
Sterol Composition ◽  
Isolation And Identification

The fungus Botrytis cinerea, which belongs to the class of ascomycetes, has been analysed for its sterol composition. It is able to produce ergosterol, cerevisterol, lanosterol/dihydrolanosterol and cholesterol besides β-sitosterol. The identification of the sterols is carried out with different analytical methods including mass spectrometry. In the extracts of the mycelium also squalene has been identified

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