RESUMO
An asymmetric synthetic route to (-)-galanthamine (1), a pharmacologically active Amaryllidaceae alkaloid used for the symptomatic treatment of early onset Alzheimer's disease, was successfully established with very high levels of stereocontrol. The key to achieving high chemo- and stereo-selectivity in this approach was the use of transition-metal-mediated reactions, namely, enyne ring-closing metathesis, Heck coupling, and titanium-based asymmetric allylation.
Assuntos
Alcaloides , Doença de Alzheimer , Galantamina , HumanosRESUMO
A series of suitable five-membered heterocyclic alternatives to thiophenes within a thienobenzoxepin class of PI3-kinase (PI3K) inhibitors was discovered. Specific thiazolobenzoxepin 8-substitution was identified that increased selectivity over PI3Kß. PI3Kß-sparing compound 27 (PI3Kß Ki,app/PI3Kα Ki,app=57) demonstrated dose-dependent knockdown of pAKT, pPRAS40 and pS6RP in vivo as well as differential effects in an in vitro proliferation cell line screen compared to pan PI3K inhibitor GDC-0941. A new structure-based hypothesis for reducing inhibition of the PI3K ß isoform while maintaining activity against α, δ and γ isoforms is presented.
Assuntos
Benzoxepinas/química , Inibidores Enzimáticos/química , Inibidores de Fosfoinositídeo-3 Quinase , Tiazóis/química , Benzoxepinas/síntese química , Benzoxepinas/farmacologia , Sítios de Ligação , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Células MCF-7 , Simulação de Acoplamento Molecular , Fosfatidilinositol 3-Quinase/metabolismo , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-akt/metabolismo , Relação Estrutura-AtividadeRESUMO
An enantioselective synthesis of (-)-galanthamine has been realized in 11 linear steps starting from isovanillin. A Mitsunobu aryl ether forming reaction was used to assemble the galanthamine backbone, which was stitched together using enyne ring-closing metathesis, Heck, and N-alkylation reactions affording the tetracyclic ring system. Control of relative and absolute stereochemistry was derived from an easily accessible enantiomerically enriched propargylic alcohol 13.
