Synthesis and muscarinic M2 subtype antagonistic activity of unnatural ent-himbacine and an enantiomeric pair of (2′S,6′R)-Diepihimbacine
摘要:
The title three compounds ent-1, 6, and ent-6 were synthesized by coupling the chiral sulfone 4 or ent-4 with the chiral piperidinaldehyde 5 or ent-5, which were readily prepared following the synthetic routes previously established by the novel total synthesis of natural himbacine 1. Their muscarinic M-2 subtype binding affinity was evaluated in comparison to that of 1, disclosing that the stereochemistry of both the tricyclic moiety and the piperidine part of 1 plays crucial roles in its potent activity. (C) 2002 Elsevier Science Ltd. All rights reserved.