Veratrole → (2,3-Dimethoxyphenyl)(4-pyridinyl)methanol

Beteiligte Stoffe

Reaktionsschritte

In yet another embodiment, there is provided a process for preparing (R)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol (3) comprising the steps of: a) reacting lithiated veratrole with 4-pyridinecarboxaldehyde (9) in the presence of a suitable aprotic solvent to provide 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]pyridine (10); b) subjecting 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]pyridine (10) to catalytic hydrogenation to provide 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]piperidine (11); c) reacting 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]piperidine (11) with a suitable 4-fluorophenylacetylating reagent, in the presence of a suitable base and a suitable solvent to provide 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]-N-2-(4-fluorophen-1-oxo-ethyl)piperidine (20); d) reacting 4-[1-hydroxy-1-(2,3-dimethoxyphenyl)methyl]-N-2-(4-fluorophen-1-oxo-ethyl)piperidine (20) with a suitable reducing agent in the presence of a suitable solvent to provide α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol (5); e) reacting α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol (5) with (2S,3S)-(+)-di-(p-anisoyl)tartaric acid to give a racemic mixture of (R)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, (2S,3S)-(+) -di-(p-anisoyl)tartaric acid salt (3a) and (S)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, (2S,3S)-(+)-di-(p-anisoyl)tartaric acid salt (3b); f) separating the (R)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, (2S,3S)-(+)-di-(p-anisoyl)tartaric acid salt (3b) from the (S)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, (2S,3S)-(+)-di-(p -anisoyl)tartaric acid salt (3a) by selective crystallization; and g) reacting the (R)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol, (2S,3S)-(+)-di-(p -anisoyl)tartaric acid salt (3a) with a suitable base to give (R)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol (3).

Herkunft & Nachweise