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Benzomorphan related compounds. IV . The stevens rearrangement of a trimethoxybenzyl‐1,2,5,6‐tetrahydropyridinium salt
Author(s) -
Bosch J.,
Canals J.,
Granados R.
Publication year - 1975
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570120606
Subject(s) - chemistry , methylamine , phenyllithium , yield (engineering) , medicinal chemistry , salt (chemistry) , bicyclic molecule , stereochemistry , organic chemistry , materials science , metallurgy
The potassium hydroxide‐induced (Stevens) rearrangement of 1,3,4‐trimethyl‐1‐(3,4,5‐trimethoxybenzyl)‐1,2,5,6‐tetrahydropyridinium chloride (I) gives the desired 1,3,4‐trimethyl‐2‐(3,4,5‐trimethoxybenzyl)‐1,2,5,6‐tetrahydropyridine (III) and the Hofmann elimination product, N ‐methyl‐ N ‐(3,4,5‐trimethoxybenzyl)‐2,3‐dimethyl‐2,4‐pentadienamine (II). In the presence of ethereal phenyllithium, the salt I undergoes rearrangement giving the expected tetrahydropyridine III in about 17% yield and four other products, N ‐(3,4,5‐trimethoxybenzyl)methylamine (VI), 1,3,4‐trimethyl‐2‐(6‐methyl‐2,3,4‐trimethoxyphenyl)‐1,2,5,6‐tetrahydropyridine (IV), 1,3,3‐trirnethyl‐2‐(3,4,5‐trimethoxyphenyl)‐4‐rnethylenepiperidine (V) and 1,3,4‐trimethyl‐4‐(3,4,5‐trimethoxybenzyl)‐1,4,5,6‐tetrahydropyridine (VII), the latter being the 1,4‐Stevens rearrangement product which cyclizes easily to β‐2′,3′,4′‐trimethoxy‐2,5,9‐trimethyl‐7,8‐benzomorphan (VIII). Their structures have been proved both by analytical and spectral data. A possible route for VIII and its stereochemical aspects are discussed.