13C-NMR and the electron impact mass spectra of the pcarboline derivatives 1 -18 were examined. The structure of the possible diastereomers is discussed. A quantitative relationship between the relative intensity of ions a in the mass spectra Of 1 -18 and the Structure Of substituents R W a s found. Struktur und spektroskopische Eigenschaften von P-Carbolinen, 1. Mitt.: '3C.NMRSij&tren und M e n s p e k t r e n der Dekahydr&H.py& do[l'J';5,1].imidazo[3,4.a].p~ar~line Die 13C-NMR-Spektren und Massenspekuen der Carbolinderivate 1 -18 wurden untersucht. Die Struktur der m6glichen Diastereomeren wird diskutien In den Massenspekuen wurde eine quantitative Komlation zwischen den relativen Intensiaten der Fragmentionen a und den Substituenten R gefunden.
The p-carbolines are an important group of compounds with a broad spectrum of activity towards the central nervous system (CNS)Is2). Hitherto the attention of our group has been focussed on the synthesis of 3.4-dihydro-and 1,2.3,4-tetrahydro-P-carbolines as potential CNS agents3-"). Some of these compounds showed a significant analgesic13), ~edative'~''~), anti-depre~sant~"~) or anticonvulsant8"') activity in animal tests. It was also demonstr9te.d that the toxicity and specific activity of the investigated pcarbolines depend on their structure, i.e. the mode of substitution and the kind of substituents8-""3). ' ) inductive substituent constants for the whole substituent taken from ref.'4.'n. *) Hanuneft constants for substituents in the phenyl ring taken from ref.'@. c, Ix" not calculated because of lack of polar constants.