Synthesis of epibatidine homologues: Homoepibatidine and bis-homoepibatidine
作者:John R Malpass、David A Hemmings、Anna L Wallis
DOI:10.1016/0040-4039(96)00687-9
日期:1996.5
based, respectively, on the tropane (8-azabicyclo[3.2.1]octane) and homotropane (9-azabicyclo[4.2.1]nonane) ring systems. Epoxy- tropanes and -homotropanes (which are readily available from simple cyclic dienes) are convenient precursors for the azabicyclic alkenes needed for the key reductive coupling with pyridine derivatives.
Stereoselective oxygenation of the homotropane ring systems; Synthesis of exo- and endo- 7-hydroxy- and 7,8-epoxyhomotropanes
作者:David E Justice、John R Malpass
DOI:10.1016/0040-4039(95)00835-z
日期:1995.6
Stereoselective introduction of an endo- epoxide into the 2-carbon bridge of the homotropane (9-azabicyclo[4.2.1]nonane) ring system has been achieved via a 4-aminocyclooct-2-enol derivative; the direct route to the exo- analogue from 7,8-dehydrohomotropanes is less efficient but the novel exo- and endo- expoxides show substantially different reactivity. Completely different tautomeric preferences
Synthesis and nicotinic acetylcholine-binding properties of epibatidine homologues: homoepibatidine and dihomoepibatidine
作者:John R. Malpass、David A. Hemmings、Anna L. Wallis、Stephen R. Fletcher、Shailendra Patel
DOI:10.1039/b010178h
日期:——
Homoepibatidine 2 and
dihomoepibatidine 3 have been synthesised
from the 8-azabicyclo[3.2.1]oct-6-ene 8
and the 9-azabicyclo[4.2.1]oct-7-ene 9,
respectively, the key precursors for reductive Heck coupling reactions. Alternative
routes starting from cyclohepta- and cycloocta-1,3-diene are described; deoxygenation
of tropane and homotropane epoxides provides a convenient route to 8 and 9.
The enantiomers of 2 show similar
potency at nicotinic receptors to the corresponding epibatidine enantiomers;
the affinity of 3 is lower.
Epoxidation of N-protected homotrop-7-ene (9-azabicyclo[4.2.1]non-7-ene) and 1-substituted derivatives occurs stereoselectively from the exo- (β-) face but a practical alternative approach to the exo- epoxides is based on a serendipitous hydride reduction of a 1-hydroxy-7β,8β-epoxyhomotropane derivative. The epoxidation of 4-aminocyclo-oct-2-enol derivatives occurs with total anti- stereoselectivity