Preparation of N-Alkylnorpavines via Competitive N-Dealkylation of Quaternary Pavines
摘要:
N-Alkyl quaternary pavine salts were converted into N-alkyl tertiary pavines by refluxing ethanolamine, via a competitive N-dealkylation mechanism. The following N-dealkylation order was observed: benzyl > allyl > Me > Et > Pr-n greater than or equal to (n)Bu. Further study indicated that N-alkyl- and N-acylpavines could be obtained from N-methyl tertiary pavines in a one-pot reaction (acid anhydride/allyl bromide or alkyl halide, reflux). This finding provides an alternative method for preparing N-alkyl tertiary pavines.
(−)-Caryachine (9) and (−)-Reframoline (10) have been synthesised from a common intermediate; this confirms the absoluteconfiguration in the isopavinane series deduced previously by application of the aromatic chirality rule. This also represents the first synthesis of an optically active pavinane alkaloid.
Lead Tetraacetate Oxidation on Caryachine, A Phenolic Pavine
作者:Chi-Ming Chiou、Shoei-Sheng Lee
DOI:10.1002/jccs.199700058
日期:1997.8
AbstractLead tetraacetate oxidation on caryachine, a pavine alkaloid possessing a phenolic group at the position para to the N‐methine, in dichloromethane yielded four products — 10‐acetoxy‐O‐acetyl‐caryachine, 10‐acetoxycaryachine, 7‐acetoxy‐O‐acetylcaryachine and (6S, 11R, 12R)‐11‐acetoxy‐O‐acetyl‐caryachine. The reaction took place via adoption of an acetoxy group at a position majorly ortho to the phenolic group, but very minorly at the desired benzylic position para to the phenolic group.