ABSTRACT
We report the discovery of a novel indoleamine 2,3-dioxygenase-1 (IDO1) inhibitor class through the affinity selection of a previously unreported indole-based DNA-encoded library (DEL). The DEL exemplar, spiro-chromane 1, had moderate IDO1 potency but high in vivo clearance. Series optimization quickly afforded a potent, low in vivo clearance lead 11. Although amorphous 11 was highly bio-available, crystalline 11 was poorly soluble and suffered disappointingly low bio-availability because of solubility-limited absorption. A prodrug approach was deployed and proved effective in discovering the highly bio-available phosphonooxymethyl 31, which rapidly converted to 11 in vivo. Obtaining crystalline 31 proved problematic, however; thus salt screening was performed in an attempt to circumvent this obstacle and successfully delivered greatly soluble and bio-available crystalline tris-salt 32. IDO1 inhibitor 32 is characterized by a low calculated human dose, best-in-class potential, and an unusual inhibition mode by binding the IDO1 heme-free (apo) form.
Subject(s)
DNA/chemistry , Enzyme Inhibitors/pharmacology , Indoleamine-Pyrrole 2,3,-Dioxygenase/antagonists & inhibitors , Prodrugs/pharmacology , Spiro Compounds/pharmacology , Animals , Drug Discovery , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Eutheria , Male , Molecular Structure , Prodrugs/chemical synthesis , Prodrugs/pharmacokinetics , Spiro Compounds/chemical synthesis , Spiro Compounds/pharmacokinetics , Structure-Activity RelationshipABSTRACT
Lead optimization of piperidine amide HTS hits, based on an anilino-thiazole core, led to the identification of analogs which displayed low nanomolar blocking activity at the canonical transient receptor channels 3 and 6 (TRPC3 & 6) based on FLIPR (carbachol stimulated) and electrophysiology (OAG stimulated) assays. In addition, the anilino-thiazole amides displayed good selectivity over other TRP channels (TRPA1, TRPV1, and TRPV4), as well as against cardiac ion channels (CaV1.2, hERG, and NaV1.5). The high oxidation potential of the aliphatic piperidine and aniline groups, as well as the lability of the thiazole amide group contributed to the high clearance observed for this class of compounds. Conversion of an isoquinoline amide to a naphthyridine amide markedly reduced clearance for the bicyclic piperidines, and improved oral bioavailability for this compound series, however TRPC3 and TRPC6 blocking activity was reduced substantially. Although the most potent anilino-thiazole amides ultimately lacked oral exposure in rodents and were not suitable for chronic dosing, analogs such as 14-19, 22, and 23 are potentially valuable in vitro tool compounds for investigating the role of TRPC3 and TRPC6 in cardiovascular disease.
Subject(s)
Aniline Compounds/chemistry , Aniline Compounds/pharmacology , TRPC Cation Channels/antagonists & inhibitors , Thiazoles/chemistry , Thiazoles/pharmacology , Diglycerides/metabolism , Drug Discovery , HEK293 Cells , Humans , TRPC Cation Channels/metabolism , TRPC6 Cation ChannelABSTRACT
Optimisation of a series of benzazepine sulfonamide hit compounds identified from high throughput screening led to the discovery of a new series of tractable, potent motilin receptor agonists.
