Electron impact mass spectrometry of some 3‐substituted 1,2,3,4‐tetrahydroisoquinolines

Abstract

956, (1 11 3) Capital Federal, ArgentinaThe electron impact mass spectral fragmentation of a series of 3-substituted-1,2,3,4-tetrahydroisoquinolinc~ are reported. The principal fragmentation modes of these compounds comply with the main generalizations reacbed earlier with simpler systems. Complete aromatizations to form the isoquinolinium ion are observed only for compounds 5 and 7 and no retro-Diels-Alder cleavage is observed when R' is a benzyl goup.

Design of A Metabolically Stable Tritium‐Tracer of the PI3Kδ‐Inhibitor CDZ173 (Leniolisib) as a Tool to Study Liver Metabolites

“…Our interpretation of the ESI‐fragmentation of CDZ173 in the MS/MS 2 spectra captures earlier interpretations of MS‐data of 1,2,3,4‐tetrahydroisoquinolines (THQ) . In these studies, the fragmentation of the piperidine moiety in THQ was interpreted to occur via a retro Diels–Alder reaction ( rDA ).…”

“…Our interpretation of the ESIfragmentation of CDZ173 in the MS/MS 2 spectra captures earlier interpretations of MS-data of 1,2,3,4tetrahydroisoquinolines (THQ). [22] [23] In these studies, the fragmentation of the piperidine moiety in THQ was interpreted to occur via a retro Diels-Alder reaction (rDA). Yet, key to our interpretation of the ESI-MS data is the assumption that the tertiary, aromatic amine function in CDZ173 (Py-N-piperidine) should have a similar low E 1/2 as the model compound tetramethyl-p-phenyldiamine (TMPD; E 1/2 = À0.28 V) [24] and therefore easily oxidizes to form a nitrogen centered radical initiating a rDAprocess.…”

Synthesis of 1-(3,4-dimethoxyphenylmethyl)-3-phenyl-6,7,8-trimethoxy-3,4-dihydroisoquinoline

“…Melting points (uncorrected) were obtained on a Thomas Hoover apparatus. The EI mass spectra were recorded in a Shimadzu CGQP 1000 mass spectrometer operating at ionizing electron energy of 70 eV or 20 eV, in all cases by direct injection of the samples as chloroform solution [12].…”

Differentiation of diastereomeric N‐aryltetrahydropyrano/tetrahydrofuranochromenylamines under electron ionization and chemical ionization conditions

“…Fragmentations due to retro‐Diels‐Alder (RDA) reactions were found to be key to the characterization of these compounds. The RDA reaction has been successfully used to characterize different cyclic systems containing a double bond in a six‐membered ring such as substituted cyclohexenes, tetralins,8 fused bicyclic,9, 10 tricyclic,11 polycyclic compounds,12–14 oxazines,15 isobenzofurans, naphthofurans,16 isoquinolines,17 chromans,18, 19 and chromones,20 and also the differentiation of isomeric compounds 21–24. RDA fragmentation has mainly been used to discriminate cis ‐ and trans ‐fused cyclic compounds, wherein cis ‐fused isomers undergo RDA reaction more favorably than trans ‐fused isomers.…”