RESUMO
8,8-Diphenyl-2,3,4,8-tetrahydroimidazo[1,5-a]pyrimidin-6-amine (1) was identified through HTS, as a weak (micromolar) inhibitor of BACE1. X-Ray crystallographic studies indicate the 2-aminoimidazole ring forms key H-bonding interactions with Asp32 and Asp228 in the catalytic site of BACE1. Lead optimization using structure-based focused libraries led to the identification of low nanomolar BACE1 inhibitors such as 20b with substituents which extend from the S(1) to the S(3) pocket.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores Enzimáticos/química , Hidantoínas/química , Imidazóis/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Sítios de Ligação , Domínio Catalítico , Cristalografia por Raios X , Descoberta de Drogas , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Hidantoínas/síntese química , Hidantoínas/farmacologia , Ligação de Hidrogênio , Imidazóis/síntese química , Imidazóis/farmacologiaRESUMO
A series of thiophene-substituted acylguanidines were designed from a pyrrole substituted acylguanidine HTS lead. This template allowed a greater flexibility, through differential Suzuki couplings, to explore the binding site of BACE1 and to enhance the inhibitory potencies. This exploration provided a 25-fold enhancement in potency to yield compound 10a, which was 150 nM in a BACE1 FRET assay.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Guanidinas/síntese química , Guanidinas/farmacologia , Tiofenos/síntese química , Tiofenos/farmacologia , Cristalografia por Raios X , Desenho de Fármacos , Indicadores e Reagentes , Modelos Moleculares , Pirróis/química , Relação Estrutura-AtividadeRESUMO
BACE1 is an aspartyl protease responsible for cleaving amyloid precursor protein to liberate Abeta, which aggregates leading to plaque deposits implicated in Alzheimer's disease. We have identified small-molecule acylguanidine inhibitors of BACE1. Crystallographic studies show that these compounds form unique hydrogen-bonding interactions with the catalytic site aspartic acids and stabilize the protein in a flap-open conformation. Structure-based optimization led to the identification of potent analogs, such as 10d (BACE1 IC(50) = 110 nM).
