Point-to-Point Ultra-Remote Asymmetric Control with Flexible Linker.

An ultra-remote intramolecular (point-to-point) asymmetric control through 38 bonds (1,39-asymmetric induction) has been achieved by using the principle of direct supramolecular orientation of catalytic and reactive moieties in asymmetric autocatalysis. We found the highly stereoselective diisopropylzinc addition reaction using designed molecules possessing pyrimidine sites at each terminal of a conformationally flexible simple methylene chain.

Synthesis and structure-activity relationships of 1-benzylindane derivatives as selective agonists for estrogen receptor beta.

The estrogen receptor beta (ERß) selective agonist is considered a promising candidate for the treatment of estrogen deficiency symptoms in ERß-expressing tissues, without the risk of breast cancer, and multiple classes of compounds have been reported as ERß selective agonists. Among them, 6-6 bicyclic ring-containing structures (e.g., isoflavone phytoestrogens) are regarded as one of the cyclized analogues of isobutestrol 5b, and suggest that other cyclized scaffolds comprising 5-6 bicyclic rings could also act as selective ERß ligands. In this study, we evaluated the selective ERß agonistic activity of 1-(4-hydroxybenzyl)indan-5-ol 7a and studied structure-activity relationship (SAR) of its derivatives. Some functional groups improved the properties of 7a; introduction of a nitrile group on the indane-1-position resulted in higher selectivity for ERß (12a), and further substitution with a fluoro or a methyl group to the pendant phenyl ring was also preferable (12b, d, and e). Subsequent chiral resolution of 12a identified that R-12a has a superior profile over S-12a. This is comparable to diarylpropionitrile (DPN) 5c, one of the promising selective ERß agonists and indicates that this indane-based scaffold has the potential to provide better ERß agonistic probes.

Design, synthesis, and structure-activity relationships of a series of 4-benzyl-5-isopropyl-1H-pyrazol-3-yl ß-D-glycopyranosides substituted with novel hydrophilic groups as highly potent inhibitors of sodium glucose co-transporter 1 (SGLT1).

Sodium glucose co-transporter 1 (SGLT1) plays a dominant role in the absorption of glucose in the gut and is considered a promising target in the development of therapeutic options for postprandial hyperglycemia. Previously, we reported potent and selective SGLT1 inhibitors 1 and 2 showing efficacy in oral carbohydrate tolerance tests in diabetic rat models. In a pharmacokinetic (PK) study of 2, excessive systemic exposure to metabolites of 2 was observed, presumably due to the high permeability of its aglycone (2a). To further improve SGLT1 inhibitory activity and reduce aglycone permeability, a series of 4-benzyl-5-isopropyl-1H-pyrazol-3-yl ß-D-glycopyranoside derivatives bearing novel hydrophilic substitution groups on the phenyl ring were synthesized and their inhibitory activity toward SGLTs was evaluated. Optimized compound 14c showed an improved profile satisfying both higher activity and lower permeability of its aglycone (22f) compared with initial leads 1 and 2. Moreover, the superior efficacy of 14c in various carbohydrate tolerance tests in diabetic rat models was confirmed compared with acarbose, an α-glucosidase inhibitor (α-GI) widely used in the clinic.

Structure-activity relationship studies of 4-benzyl-1H-pyrazol-3-yl ß-d-glucopyranoside derivatives as potent and selective sodium glucose co-transporter 1 (SGLT1) inhibitors with therapeutic activity on postprandial hyperglycemia.

Sodium glucose co-transporter 1 (SGLT1) plays a dominant role in the absorption of glucose in the gut and is considered a promising target in the development of treatments for postprandial hyperglycemia. A series of 4-benzyl-1H-pyrazol-3-yl ß-d-glucopyranoside derivatives have been synthesized, and its inhibitory activity toward SGLTs has been evaluated. By altering the substitution groups at the 5-position of the pyrazole ring, and every position of the phenyl ring, we studied the structure-activity relationship (SAR) profiles and identified a series of potent and selective SGLT1 inhibitors. Representative derivatives showed a dose-dependent suppressing effect on the escalation of blood glucose levels in oral mixed carbohydrate tolerance tests (OCTT) in streptozotocin-nicotinamide-induced diabetic rats (NA-STZ rats).

Evaluating the correlation of binding affinities between isothermal titration calorimetry and fragment molecular orbital method of estrogen receptor beta with diarylpropionitrile (DPN) or DPN derivatives.

Estrogen receptors (ERs) are ligand-activated transcription factors, with two subtypes ERα and ERß. The endogenous ligand of ERs is the common 17ß-estradiol, and the ligand-binding pocket of ERα and ERß is very similar. Nevertheless, some ERß-selective agonist ligands have been reported. DPN (diarylpropionitrile) is a widely used ERß-selective agonist; however, the structure of the ERß-DPN complex has not been solved. Therefore, the bound-state conformation of DPN and its enantioselectivity remain unresolved. In this report, we present the structures of the complexes of ERß with DPN or its derivatives that include a chlorine atom by the X-ray crystallography. Additionally, we measured the binding affinity between ERß and DPN or derivatives by isothermal titration calorimetry (ITC) and estimated the binding affinity by fragment molecular orbital (FMO) calculations. We also examined the correlation between the ITC data and results from the FMO calculations. FMO calculations showed that S-DPN interacts strongly with three amino acids (Glu305, Phe356, and His475) of ERß, and ITC measurements confirmed that the chlorine atom of the DPN derivatives enhances binding affinity. The enthalpy change by ITC correlated strongly with the interaction energy (total IFIEs; inter-fragment interaction energies) calculated by FMO (R = 0.870). We propose that FMO calculations are a valuable approach for enhancing enthalpy contributions in drug design, and its scope of applications includes halogen atoms such as chlorine. This study is the first quantitative comparison of thermodynamic parameters obtained from ITC measurements and FMO calculations, providing new insights for future precise drug design.

Novel oestrogen receptor ß-selective ligand reduces obesity and depressive-like behaviour in ovariectomized mice.

Hormonal changes due to menopause can cause various health problems including weight gain and depressive symptoms. Multiple lines of evidence indicate that oestrogen receptors (ERs) play a major role in postmenopausal obesity and depression. However, little is known regarding the ER subtype-specific effects on obesity and depressive symptoms. To delineate potential effects of ERß activation in postmenopausal women, we investigated the effects of a novel oestrogen receptor ß-selective ligand (C-1) in ovariectomized mice. Uterine weight, depressive behaviour, and weight gain were examined in sham-operated control mice and ovariectomized mice administered placebo, C-1, or 17ß-oestradiol (E2). Administration of C-1 or E2 reduced body weight gain and depressive-like behaviour in ovariectomized mice, as assessed by the forced swim test. In addition, administration of E2 to ovariectomized mice increased uterine weight, but administration of C-1 did not result in a significant increase in uterine weight. These results suggest that the selective activation of ERß in ovariectomized mice may have protective effects against obesity and depressive-like behaviour without causing an increase in uterine weight. The present findings raise the possibility of the application of ERß-ligands such as C-1 as a novel treatment for obesity and depression in postmenopausal women.

Practically Perfect Asymmetric Autocatalysis with (2-Alkynyl-5-pyrimidyl)alkanols.

Extremely high enantioselectivity (>99.5% ee) and chemical yield (>99%) are achieved in an asymmetric autocatalytic reaction. A (5-pyrimidyl)alkanol with a tert-butylethynyl group at its 2-position (1) is a very efficient asymmetric autocatalyst in the enantioselective alkylation in Equation (1).