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Der F ISCHER 'sche Indolringschluss mit 1, 3‐disubstituierten 4‐Piperidonen . 7. Mitteilung über synthetische Indolverbindungen [1]
Author(s) -
Ebnöther A.,
Niklaus P.,
Süess R.
Publication year - 1969
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19690520311
Subject(s) - chemistry , substituent , piperidine , catalysis , medicinal chemistry , hydrogen chloride , stereochemistry , organic chemistry
Abstract Treatment of the arylhydrazones of 1, 3‐disubstituted 4‐piperidones with ethanolic hydrogen chloride (F ISCHER reaction conditions) affords 1, 2, 3, 4‐tetrahydropyrimido [3, 4‐a]‐indoles in good yields. During catalytic hydrogenation in the presence of protons these tetrahydropyrimido‐indoles are split into 2‐(2‐methylamino‐ethyl)‐indoles. The formation of these tricyclic products can be explained by rearrangement immediately following the normal F ISCHER reaction. If the substituent at the piperidine nitrogen is an acyl group, normal or rearranged products are formed, depending on the nature of the 3‐substituent.