Discovery of DS-3801b, a non-macrolide GPR38 agonist with N-methylanilide structure.

Motilin is a 22-amino-acid gastrointestinal (GI) hormone and is involved in the regulation of GI motility through binding to GPR38, the motilin receptor which is expressed on smooth muscle cells in the GI tract. Therefore, GPR38 agonists are expected to be novel gastrointestinal prokinetic agents for the treatment of functional gastrointestinal disorders such as gastroparesis and chronic constipation. We identified a series of N-methylanilide derivatives as novel non-macrolide GPR38 agonists. Among them, 12 di-l-tartrate (DS-3801b) was selected as a clinical candidate for further evaluation.

Optimization of 3-aryl-3-ethoxypropanoic acids and discovery of the potent GPR40 agonist DS-1558.

GPR40 agonists stimulate insulin secretion only under the presence of high glucose concentration. Based on this mechanism, GPR40 agonists are believed to be promising novel insulin secretagogues with low risk of hypoglycemia. The optimizations of 3-aryl-3-ethoxypropanoic acids were performed to improve in vitro activity. We discovered compound 29r (DS-1558), (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid, which was confirmed to have an enhancing effect on glucose-dependent insulin secretion after intravenous glucose injection in SD rats.

Discovery of DS-1558: A Potent and Orally Bioavailable GPR40 Agonist.

GPR40 is a G protein-coupled receptor that is predominantly expressed in pancreatic ß-cells. GPR40 agonists stimulate insulin secretion in the presence of high glucose concentration. On the basis of this mechanism, GPR40 agonists are possible novel insulin secretagogues with reduced or no risk of hypoglycemia. The improvement of in vitro activity and metabolic stability of compound 1 led to the discovery of 13, (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid, as a potent and orally available GPR40 agonist. Compound 13 (DS-1558) was found to have potent glucose lowering effects during an oral glucose tolerance test in ZDF rats.

Discovery of 3-aryl-3-ethoxypropanoic acids as orally active GPR40 agonists.

The G protein-coupled receptor 40 (GPR40) mediates enhancement of glucose-stimulated insulin secretion in pancreatic ß cells. The GPR40 agonist has been attracting attention as a novel insulin secretagogue with glucose dependency for the treatment of type 2 diabetes. The optimization study of compound 1 led to a potent and bioavailable GPR40 agonist 24, which showed insulin secretion and glucose lowering effects in rat OGTT. Compound 24 is a potential lead compound for a novel insulin secretagogue with a low risk of hypoglycemia.

Potentiation of insulin secretion and improvement of glucose intolerance by combining a novel G protein-coupled receptor 40 agonist DS-1558 with glucagon-like peptide-1 receptor agonists.

G protein-coupled receptor 40 (GPR40) is a Gq-coupled receptor for free fatty acids predominantly expressed in pancreatic ß-cells. In recent years, GPR40 agonists have been investigated for use as novel therapeutic agents in the treatment of type 2 diabetes. We discovered a novel small molecule GPR40 agonist, (3S)-3-ethoxy-3-(4-{[(1R)-4-(trifluoromethyl)-2,3-dihydro-1H-inden-1-yl]oxy}phenyl)propanoic acid (DS-1558). The GPR40-mediated effects of DS-1558 on glucose-stimulated insulin secretion were evaluated in isolated islets from GPR40 knock-out and wild-type (littermate) mice. The GPR40-mediated effects on glucose tolerance and insulin secretion were also confirmed by an oral glucose tolerance test in these mice. Furthermore, oral administration of DS-1558 (0.03, 0.1 and 0.3mg/kg) significantly and dose-dependently improved hyperglycemia and increased insulin secretion during the oral glucose tolerance test in Zucker fatty rats, the model of insulin resistance and glucose intolerance. Next, we examined the combination effects of DS-1558 with glucagon like peptide-1 (GLP-1). DS-1558 not only increased the glucose-stimulated insulin secretion by GLP-1 but also potentiated the maximum insulinogenic effects of GLP-1 after an intravenous glucose injection in normal Sprague Dawley rats. Furthermore, the glucose lowering effects of exendin-4, a GLP-1 receptor agonist, were markedly potentiated by the DS-1558 (3mg/kg) add-on in diabetic db/db mice during an intraperitoneal glucose tolerance test. In conclusion, our results indicate that add-on GPR40 agonists to GLP-1 related agents might be a potential treatment compared to single administration of these compounds. Therefore the combinations of these agents are a novel therapeutic option for type 2 diabetes.

Potent and Orally Bioavailable GPR142 Agonists as Novel Insulin Secretagogues for the Treatment of Type 2 Diabetes.

GPR142 is a G protein-coupled receptor that is predominantly expressed in pancreatic ß-cells. GPR142 agonists stimulate insulin secretion in the presence of high glucose concentration, so that they could be novel insulin secretagogues with reduced or no risk of hypoglycemia. We report here the optimization of HTS hit compound 1 toward a proof of concept compound 33, which showed potent glucose lowering effects during an oral glucose tolerance test in mice and monkeys.

Organocatalytic amidation and esterification of aldehydes with activating reagents by a cross-coupling strategy.

Formation on demand: An organocatalytic cross-coupling reaction of aldehydes with N-hydroxyimides, hexafluoroisopropyl alcohol, and sulfonimides has been developed. The resulting active intermediates can be directly converted into amides or esters in one pot. This simple method makes use of readily available starting materials, and the newly discovered activating reagents should find broad application in the synthesis of amides and esters.

A chemically programmed antibody is a long-lasting and potent inhibitor of influenza neuraminidase.

Programming an anti-flu strategy: A new and potent neuraminidase inhibitor that maintains long-term systemic exposure of an antibody and the therapeutic activity of the neuraminadase inhibitor zanamivir has been created. This strategy could provide a promising new class of influenza A drugs for therapy and prophylaxis, and validates enzyme inhibitors as programming agents in synthetic immunology.

Development of an efficient therapeutic agent for Alzheimer's disease: design and synthesis of dual inhibitors of acetylcholinesterase and serotonin transporter.

To date, acetylcholinesterase (AChE) inhibitors have been clinically effective drugs for the palliative treatment of Alzheimer's disease, but their clinical efficacy is limited, mainly due to their adverse effects on peripheral organs. Since patients of Alzheimer's disease often exhibit depression as well as memory impairment, dual inhibitors of AChE and serotonin transporter (SERT) would be a better therapeutic method. Anti-depressive effects based on SERT inhibition would reduce the dose-related side effects of AChE inhibitors. Such dual inhibitors were designed by the hybridization of rivastigmine and fluoxetine based on a hypothetical model of the AChE active site. Various derivatives were synthesized and evaluated for their in vitro inhibition, and then (S)-5j (RS-1259), which possessed balanced inhibitory activities of AChE (IC(50)=101 nM) and SERT (IC(50)=42 nM), was successfully obtained. An ex vivo experiment in mice indicated that (S)-5j (RS-1259) simultaneously inhibited AChE and SERT in the brain following an oral administration. The simultaneous elevation of extracellular levels of acetylcholine and serotonin in the rat hippocampus was actually confirmed by microdialysis.

Transition-metal-catalyzed sequential cross-coupling of bis(iodozincio)methane and -ethane with two different organic halides.

Bis(iodozincio)methane, prepared from diiodomethane and zinc, reacts with an organic halide in the presence of a transition-metal catalyst to give an iodozinciomethylenated compound; this then reacts with another organic halide to form a C--C bond. The overall process connects two electrophiles with one carbon atom. Bis(iodozincio)ethane can also undergo this transformation, yielding a new stereogenic center. The asymmetric induction of this stereogenic center was investigated by using a chiral palladium catalyst.

A conformational restriction approach to the development of dual inhibitors of acetylcholinesterase and serotonin transporter as potential agents for Alzheimer's disease.

Alzheimer's disease (AD) has been treated with acetylcholinesterase (AChE) inhibitors such as donepezil. However, the clinical usefulness of AChE inhibitors is limited mainly due to their adverse peripheral effects. Depression seen in AD patients has been treated with serotonin transporter (SERT) inhibitors. We considered that combining SERT and AChE inhibition could improve the clinical usefulness of AChE inhibitors. In a previous paper, we found a potential dual inhibitor, 1, of AChE (IC50=101 nM) and SERT (IC50=42 nM), but its AChE inhibition activity was less than donepezil (IC50=10 nM). Here, we report the conformationally restricted (R)-18a considerably enhanced inhibitory activity against AChE (IC50=14 nM) and SERT (IC50=6 nM).

Pharmacological characterization of RS-1259, an orally active dual inhibitor of acetylcholinesterase and serotonin transporter, in rodents: possible treatment of Alzheimer's disease.

A dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT), RS-1259 (4-[1S)-methylamino-3-(4-nitrophenoxy)]propylphenyl N,N-dimethylcarbamate (fumaric acid)(1/2)salt), was newly synthesized. RS-1259 simultaneously inhibited AChE and SERT in the brain following an oral administration in mice and rats. Actual simultaneous elevation of extracellular levels of 5-HT and ACh in the rat hippocampus was confirmed by microdialysis. The compound was as effective as SERT inhibitors such as fluoxetine and fluvoxamine in a 5-hydroxytryptophan-enhancing test in mice. Spatial memory deficits in the two-platform task of a water maze in aged rats were ameliorated by RS-1259 as well as donepezil. Both RS-1259 and donepezil increased the awake episodes in the daytime electroencephalogram of rats. Although RS-1259 was weaker than donepezil in enhancing central cholinergic transmission, as observed by ACh elevation in the hippocampus and memory enhancement in aged rats, the efficacy of RS-1259 on the consciousness level, which reflects the whole activity in the brain, was almost the same as that of donepezil. These results suggest that both cholinergic and serotonergic systems are involved in maintaining brain arousal and that a dual inhibitor of AChE and SERT may be useful for the treatment of cognitive disorders associated with reduced brain activity such as in Alzheimer's disease.

Design, synthesis and structure-activity relationships of dual inhibitors of acetylcholinesterase and serotonin transporter as potential agents for Alzheimer's disease.

We have designed and synthesized a dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT) as a novel class of treatment drugs for Alzheimer's disease on the basis of a hypothetical model of the AChE active site. Dual inhibitions of AChE and SERT would bring about greater therapeutic effects than AChE inhibition alone and avoid adverse peripheral effects caused by excessive AChE inhibition. Compound (S)-6j exhibited potent inhibitory activities against AChE (IC(50)=101 nM) and SERT (IC(50)=42 nM). Furthermore, (S)-6j showed inhibitory activities of both AChE and SERT in mice brain following oral administration.

Total synthesis of (+)-benzastatin E via diastereoselective Grignard addition to 2-acylindoline.

[reaction: see text] A stereoselective total synthesis of (+)-benzastatin E (1) is described. The synthesis involves a diastereoselective Grignard addition to 2-acylindoline 2, which is derived from commercially available (S)-2-indolinecarboxylic acid (3). The unknown absolute configuration of (+)-1 is determined as (9S,10R).

Design and synthesis of dual inhibitors of acetylcholinesterase and serotonin transporter targeting potential agents for Alzheimer's disease.

Highly efficient acetylcholinesterase (AChE) and serotonin transporter (SERT) dual inhibitors, (S)-4 and (R)-13 were designed and synthesized on the basis of the hypothetical model of AChE active site. Both compounds showed potent inhibitory activities against AChE and SERT. [structure: see text]