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The objective of this Letter is to report the first (to our knowledge) in vivo proof of concept for a sulfenamide prodrug to orally deliver a poorly soluble drug containing a weakly-acidic NH–acid from a conventional solid dosage formulation. This proof of concept was established using BMS–708163 (1), a gamma secretase inhibitor containing a weakly acidic primary amide NH-acid as the chemical handle for attaching a series of thiol-based promoieties via a sulfenamide linkage. Aqueous stabilities and solubilities are reported for a series of six sulfenamide prodrugs (2–7) of 1. The sulfenamide prodrug containing the cysteine methyl ester promoiety (5) was chosen for a orally-dosed PK study in male beagle dog comparing a solubilized formulation of 1 against a solid dosage form of 5 in a cross-over fashion at an equivalent molar dose of 3 mg/kg. Prodrug 5 delivered essentially a superimposable PK profile of 1 compared to the solubilized formulation of 1, without any detectable exposure of 5 in systemic circulation.

The therapeutic treatment of negative symptoms and cognitive dysfunction associated with schizophrenia is a significant unmet medical need. Preclinical literature indicates that α7 neuronal nicotinic acetylcholine (nACh) receptor agonists may provide an effective approach to treating cognitive dysfunction in schizophrenia. We report herein the discovery and evaluation of 1c (BMS-933043), a novel and potent α7 nACh receptor partial agonist with high selectivity against other nicotinic acetylcholine receptor subtypes (>100-fold) and the 5-HT3A receptor (>300-fold). In vivo activity was demonstrated in a preclinical model of cognitive impairment, mouse novel object recognition. BMS-933043 has completed Phase I clinical trials.

A convergent synthesis route for the heterocyclic modification of a novel bicyclo[3.1.0]hexane NPY1 antagonist 2 was developed and the structure activity relationship of these modifications on NPY1 binding is reported. Two heterocyclic analogs 9 and 10 showed comparable Y1 binding potency to 2, but with improved aqueous solubility. Compound 9 demonstrated reduced spontaneous nocturnal food intake in a rat model when dosed ip. Compound 9 was also shown to be orally bioavailable and brain penetrable.

We describe the synthesis of quinuclidine-containing spiroimidates and their utility as α7 nicotinic acetylcholine receptor (nAChR) partial agonists. A convergent synthetic route allowed for rapid SAR investigation and provided a diverse set of fused 6,5-heteroaryl analogs. Two potent and selective α7 nAChR partial agonists, (1′S,3′R,4′S)-N-(7-bromopyrrolo[2,1-f][1,2,4]triazin-4-yl)-4H-1′-azaspiro[oxazole-5,3′-bicyclo[2.2.2]octan]-2-amine (20) and (1′S,3′R,4′S)-N-(7-chloropyrrolo[2,1-f][1,2,4]triazin-4-yl)-4H-1′-azaspiro[oxazole-5,3′-bicyclo[2.2.2]octan]-2-amine (21), were identified. Both agonists improved cognition in a preclinical rodent model of learning and memory. Additionally, 5-HT3A receptor SAR suggested the presence of a steric site that when engaged led to significant loss of affinity at that receptor.

A series of 3-[6-(4-substituted-piperazin-1-yl)-4-methyl-1H-benzimidazol-2-yl]-1H-pyridine-2-one were synthesized to modulate CYP3A4 inhibition and improve aqueous solubility of our prototypical compound BMS-536924 (1), while maintaining potent IGF-1R inhibitory activity. Structure-activity and structure-solubility studies led to the identification of BMS-577098 (27), which demonstrates oral in vivo efficacy in animal models. The improvement was achieved by replacing morpholine with more polar bio-isoster piperazine and modulating the basicity of distal nitrogen with appropriate substitutions.

A series of novel 5,5-diphenylimidazolones was synthesized and evaluated for activity against the human neuropeptide Y5 receptor. The 3-pyridyl analog 46 demonstrated an IC 50 of 8.3 nM with a favorable pharmacokinetic profile in rats, but was ineffective in reducing food intake.

Structure–activity studies around the urea linkage in BMS-193885 ( 4a ) identified the cyanoguanidine moiety as an effective urea replacement in a series of dihydropyridine NPY Y 1 receptor antagonists. In comparison to urea 4a ( K i =3.3 nM), cyanoguanidine 20 (BMS-205749) displayed similar binding potency at the Y 1 receptor ( K i =5.1 nM) and full functional antagonism ( K b =2.6 nM) in SK-N-MC cells. Cyanoguanidine 20 also demonstrated improved permeability properties in Caco-2 cells in comparison to urea 4a (43 vs 19 nm/s).

A series of 4-bicyclic heteroaryl 1,2,3,4-tetrahydroisoquinoline inhibitors of the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) was discovered. The synthesis and structure-activity relationship (SAR) of these triple reuptake inhibitors (TRIs) will be discussed. Compound 10i (AMR-2), a very potent inhibitor of SERT, NET, and DAT, showed efficacy in the rat forced-swim and mouse tail suspension models with minimum effective doses of 0.3 and 1 mg/kg (po), respectively. At efficacious doses in these assays, 10i exhibited substantial occupancy levels at the three transporters in both rat and mouse brain. The study of the metabolism of 10i revealed the formation of a significant active metabolite, compound 13.

The identification of a potent series of IKK-β selective inhibitors based on an imidazothienopyrazine template and the oral efficacy of one such analog (22j) in the LPS-induced TNF-α release mouse model are described.