Synthetic studies of himbacine, a potent antagonist of the muscarinic M2 subtype receptor 1. Stereoselective total synthesis and antagonistic activity of enantiomeric pairs of himbacine and (2′S,6′R)-diepihimbacine, 4-epihimbacine, and novel himbacine congeners
Total synthesis of an enantiomeric pair of himbacine 1 and ent-1 was achieved in a highly stereoselective manner by employing an intermolecular Diels–Alder reaction of tetrahydroisobenzofuran 8 with chiral furan-2(5H)-one (S)-9 and (R)-9, respectively, as a key step. An enantiomeric pair of (2′S,6′R)-diepihimbacine 24 and ent-24, 4-epihimbacine 4-epi-1, and novel himbacine congeners bearing the same
Synthesis and muscarinic M2 subtype antagonistic activity of unnatural ent-himbacine and an enantiomeric pair of (2′S,6′R)-Diepihimbacine
作者:Masanori Takadoi、Shiro Terashima
DOI:10.1016/s0960-894x(02)00566-8
日期:2002.10
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.