Toward Asymmetric Synthesis of Pentaorganosilicates.

Introducing chiral silicon centers was explored for the asymmetric Rh-catalyzed cyclization of dihydrosilanes to enantiomerically enriched spirosilanes as targets to enable access to enantiostable pentacoordinate silicates. The steric rigidity required in such systems demands the presence of two naphthyl or benzo[b]thiophene groups. The synthetic approach to the expanded spirosilanes extends Takai's method (Kuninobu et al.

Synthesis of new dipyrido-annulated N-heterocyclic carbenes with ortho substituents.

A method for the introduction of various substituents at the 4 and 8 positions of 2,10-di-tert-butyldipyrido[1,2-c;2',1'-e]imidazolium salts, is described. The new imidazolium salts bearing substituents (R' = Cl, SPh) at the 4 and 8 positions are synthesized in three-step procedures, and carbenes generated from the imidazolium salts can be used to give the corresponding rhodium complexes. The role of the 4,8-substituents can be either bystanders or coordinating ligands according to the nature of the metal moiety.

Impact of diradical character on two-photon absorption: bis(acridine) dimers synthesized from an allenic precursor.

The two-photon absorption (TPA) of a bis(acridine) dimer (8) having singlet diradical character in its ground state was found to be enhanced by more than 2 orders of magnitude as compared to its closed-shell counterpart (12), which has the same structural backbone and atom composition. The dimer, a tetracation species consisting of two connected acridinium cation moieties with high coplanarity, was obtained during our attempts to synthesize triplet carbenes by double oxidation of an allenic precursor (3b). High conjugation over the two aromatic rings connected by dimerization was revealed by X-ray analysis, and a small HOMO-LUMO gap was found in the visible-near-infrared one-photon absorption spectrum in solution and in the crystalline state, exhibiting that the ground state of 8 has singlet diradical nature.

Sulfonylurea agents exhibit peroxisome proliferator-activated receptor gamma agonistic activity.

Sulfonylurea (SU) agents, including glimepiride and glibenclamide, are the most widely used oral hypoglycemic drugs, which stimulate insulin secretion primarily by binding to the SU receptor on the plasma membrane of pancreatic beta-cells. Thiazolidinediones, such as pioglitazone and rosiglitazone, are other hypoglycemic agents that effectively improve peripheral insulin resistance through activation of peroxisome proliferator-activated receptor gamma (PPARgamma). In the present study, we found that glimepiride specifically induced the transcriptional activity of PPARgamma in luciferase reporter assays.

CYP3A5 genotype did not impact on nifedipine disposition in healthy volunteers.

CYP3A5 expression is regulated by single-nucleotide polymorphisms (SNPs). The CYP3A5 genotype might contribute to a marked interindividual variation in CYP3A-mediated metabolism of drugs. Nifedipine is a typical substrate of CYP3A4 and CYP3A5 in vitro.