ABSTRACT
The structure activity relationship of the prime region of conformationally restricted hydroxyethylamine (HEA) BACE inhibitors is described. Variation of the P1' region provided selectivity over Cat-D with a series of 2,2-dioxo-isothiochromanes and optimization of the P2' substituent of chromane-HEA(s) with polar substituents provided improvements in the compound's in vitro permeability. Significant potency gains were observed with small aliphatic substituents such as methyl, n-propyl, and cyclopropyl when placed at the C-2 position of the chromane.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Chromans/chemistry , Drug Design , Enzyme Inhibitors/chemical synthesis , Binding Sites , Cells, Cultured , Ethylamines/chemical synthesis , Ethylamines/chemistry , Ethylamines/pharmacology , Inhibitory Concentration 50 , Models, Molecular , Structure-Activity RelationshipABSTRACT
The structure-activity relationship of the prime region of hydroxyethylamine BACE inhibitors is described. Variation in the aryl linker region with 5- and 6-membered heterocycles provided compounds such as 33 with improved permeability and reduced P-gp liability compared to benzyl amine analog 1.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Aspartic Acid Endopeptidases/antagonists & inhibitors , Aspartic Acid Endopeptidases/metabolism , Ethylamines/chemistry , Ethylamines/pharmacology , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/chemistry , Aspartic Acid Endopeptidases/chemistry , Crystallography, X-Ray , Ethylamines/chemical synthesis , Humans , Models, Molecular , Protease Inhibitors/chemical synthesis , Protein Binding , Structure-Activity RelationshipABSTRACT
The hydroxyethylene (HE) transition state isostere was developed as a scaffold to provide potent, small molecule inhibitors of human beta-secretase (BACE). The previous work on the statine series proved critical to the discovery of HE structure-activity relationships. Compound 20 with the N-terminal isophthalamide proved to be the most potent HE inhibitor (IC(50) = 30 nM) toward BACE. Unlike the statine series, we identified HE inhibitors without carboxylic acids on the C terminus, leading to enhanced cell penetration and making them attractive candidates for further drug development in Alzheimer's disease.
Subject(s)
Amides/chemical synthesis , Aspartic Acid Endopeptidases/chemistry , Dipeptides/chemistry , Ethylenes/chemical synthesis , Phthalic Acids/chemical synthesis , Protease Inhibitors/chemical synthesis , Amides/chemistry , Amyloid Precursor Protein Secretases , Drug Design , Endopeptidases , Ethylenes/chemistry , Humans , Models, Molecular , Molecular Mimicry , Phthalic Acids/chemistry , Protease Inhibitors/chemistry , Structure-Activity RelationshipABSTRACT
We describe the development of statine-based peptidomimetic inhibitors of human beta-secretase (BACE). The conversion of the peptide inhibitor 1 into cell-permeable peptidomimetic inhibitors of BACE was achieved through an iterative strategy of conceptually subdividing 1 into three regions: an N-terminal portion, a central statine-containing core, and a C-terminus. Replacement of the amino acid residues of 1 with moieties with less peptidic character was done with retention of BACE enzyme inhibitory activity. This approach led to the identification of the cell-permeable BACE inhibitor 38 that demonstrated BACE-mechanism-selective inhibition of Abeta secretion in human embryonic kidney cells.
