Derivatization and mass spectrometric behaviour of catecholamines and their 3-O-methylated metabolites

A method has been developed for the derivatization of both catecholamines (dopamine, noradrenaline and adrenaline) and their 3-O-methylated metabolites (3-methoxytyramine, normetanephrine and metanephrine) in a single run. The compounds were first incubated with methanolic hydrochloric acid to methylate those compounds that contain a benzylic hydroxyl group and were subsequently converted into their pentafluoropropionyl derivatives. The derivatives thus prepared, showed good gas chromatographic and electron-impact mass spectrometric properties and can be analysed in a single gas chromatographic run. The effect of the derivatization on exchange reactions in the aromatic ring was investigated because standard compounds with deuterium label in that part of the molecule are often used in isotope dilution measurements. The exchange of deuterium for hydrogen in the aromatic ring under derivatization conditions was found to be limited.     

Reaktionen an komplexgebundenen liganden : XXXIII. Synthese,reaktivität und struktur von eisen-carbonyl-komplexen mit vierzähnigen thioäther-thiolato-liganden

The reaction of the anion [Fe(CO)₂(S₂C₆H₄)₂]^2? with 1,2-C₂H₄Br₂ yields [Fe(CO)₂(dttd)] containing the dianion of the new tetradentate thioether-thiol ligand 2,3,8,9-dibenzo-1,4,7,10-tetrathiadecan (dttd-H₂). Iron(II) salts coordinate CO under normal conditions also in the presence of alkyl mercaptides; the reaction of, e.g., Fe²⁺, 1,2-S₂C₂H₄^2? and CO yields [Fe(CO)₂(S₂C₂H₄)]^2? which reacts with 1,2-C₂H₄Br₂ analogously yielding [Fe(CO)₂(tdd)], (ttd = [1,4,7,10-tetrathiadecane]^2?). As shown by X-ray analysis the iron centre in [Fe(CO)₂(ttd)] is coordinated pseudo-octahedrally by four sulfur atoms and two cis-carbonyl groups. [Fe(CO)₂(dttd)] splits off one CO ligand upon heating in THF yielding [Fe(CO)(dttd)], which on reaction with PMe₃ yields [Fe(CO)(PMe₃)(dttd)]. The new complexes are characterized by elemental analyses as well as by IR, ¹H NMR and mass spectroscopy.