Bicyclic peptidomimetic tetrahydrofuro[3,2-b]pyrrol-3-one and hexahydrofuro[3,2-b]pyridine-3-one based scaffolds: synthesis and cysteinyl proteinase inhibition.
A stereoselective synthesis of (3aS,6aR)-tetrahydrofuro[3,2-b]pyrrol-3-ones and (3aS,7aR)-hexahydrofuro[3,2-b]pyridine-3-ones has been developed through Fmoc protected scaffolds 12 and 13. A key design element within these novel bicyclic scaffolds, in particular the 5,5-fused system, was the inherent stability of the cis-fused geometry in comparison to that of the corresponding trans-fused. Since the bridgehead stereocentre situated beta to the ketone was of a fixed and stable configuration, the fact that cis ring fusion is both kinetically and thermodynamically stable with respect to trans ring fusion provides chiral stability to the bridgehead stereocentre that is situated alpha to the ketone. To exemplify this principle, building blocks 12 and 13 were designed, prepared and utilised in a solid phase combinatorial synthesis of peptidomimetic inhibitors 10, 45a-e, 11 and 46. Both series were chirally stable with 5,5-series 10 and 45a-e exhibiting potent in vitro activity against a range of CAC1 cysteinyl proteinases. Compound 10, a potent and selective inhibitor of cathepsin K, possessed good primary DMPK properties along with promising activity in an in vitro cell-based human osteoclast assay of bone resorption.
Amura Therapeutics Limited, Incenta House, Horizon Park, Barton Road, Comberton, Cambridge CB3 7AJ, UK. martin.quibell@incenta.co.uk
Martin
M
Quibell
Alex
A
Benn
Nick
N
Flinn
Tracy
T
Monk
Manoj
M
Ramjee
Yikang
Y
Wang
John
J
Watts
D000818:Animals; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000494:pharmacology; D002417:Cattle; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology; D006801:Humans; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D011725:Pyridines / Q000138:chemical synthesis* / Q000494:pharmacology
D001643:Bridged Bicyclo Compounds; D015853:Cysteine Proteinase Inhibitors; D011725:Pyridines; D003546:Cysteine Endopeptidases