Syntheses of Aryl Thioethers via Aromatic Substitution of Aryl Halides at 0 to 25 °C.

In this study, we developed mild conditions for the synthesis of an aryl thioether via aromatic substitution using aryl halides, which is a process that has rarely been studied. Aromatic substrates such as aryl fluorides activated with a halogen substituent are difficult to use for substitution reactions, but by using 18-crown-6-ether as an additive, these were successfully converted to their corresponding thioether products. Under the conditions we established, in addition to a wide variety of thiols, less-toxic and odorless disulfides could be used directly as nucleophiles at 0 to 25 °C.

Etherification via Aromatic Substitution on 1,3-Disubstituted Benzene Derivatives.

In this study, we developed a method for etherification via aromatic substitution at the ipso-position of an electron-withdrawing group (EWG) that exists at the meta-position of another EWG. To heighten the reactivity of the substitution reaction, we added a -BuOK solution in tetrahydrofuran (THF) to a mixture of an aromatic substrate, an alcoholic nucleophile, and 18-crown-6-ether in dimethylformamide (DMF), which proved to be a particularly effective sequence. Under the conditions we established, aromatic substrates that are difficult to use for substitution reactions such as aryl fluorides activated with either a bromide or a chloride substituent were aptly converted to corresponding ether products at 25 °C.

Aryl Ether Syntheses via Aromatic Substitution Proceeding under Mild Conditions.

In this study, mild conditions for aromatic substitutions during the syntheses of aryl ethers were developed. In the reaction conditions, the choices of solvent, base, and the sequence for the addition of the reagents proved important. A wide variety of alcohols were used directly as nucleophiles and smoothly reacted with aryl chlorides that possessed either a nitro or a cyano group at either the ortho- or para-position.

Influences of Phenyl Rings on NHC Ligands with Bicyclic Architectures.

In addition to phosphanes, olefins, amines, and amides, over the past two decades N-heterocyclic carbene (NHC) has emerged as a useful alternative ligand. Based on a number of derivatization studies on NHC ligands, imidazol-2-ylidene and imidazolin-2-ylidene became the standard heterocyclic form, and bulky substituents have commonly been introduced on the nitrogen(s) adjacent to carbenic carbons. Our group previously developed NHCs equipped with noncarbenic carbons with a bicyclic architecture that gives them unique steric properties that make them bulky but accessible.

A Study of the Strength of a Template Molecule-A Functional Monomer Interaction That Affects the Performance of Molecularly Imprinted Polymers and Its Application to Chiral Amplification.

A novel type of molecularly imprinted polymer (MIP), N-benzoyl-(S)-valine anilide-imprinted polymer (IP-2), was prepared using hydrogen-bonding interactions as a main force in the pre-polymerization step. The performance of the IP-2 was evaluated via batch procedure and compared with a (S)-valine anilide-imprinted polymer (IP-1) that was prepared using an ionic interaction that is stronger than hydrogen bonding. Although both polymers showed a preferential adsorbability for (S)-amino acid derivatives, different performances were observed in terms of adsorbability and enantioselectivity.

A dramatic synergistic effect of a flexible achiral linker on a rigid chiral cis-1,2-diamine bifunctional organocatalyst.

The combination of a "rigid" chiral bicyclic cis-1,2-diamine skeleton with steric bulkiness and a "flexible" achiral linker was newly designed as a bifunctional organocatalyst framework and it showed excellent catalytic activity of up to 0.05 mol%, accompanied by the reversal of enantioselection depending on the position of the linker, in an amine-thiourea organocatalyzed asymmetric Michael reaction.

An N-Heterocyclic Carbene-Nickel Half-Sandwich Complex as a Precatalyst for Suzuki-Miyaura Coupling of Aryl/Heteroaryl Halides with Aryl/Heteroarylboronic Acids.

A nickel half-sandwich complex supported by our original NHC ligand was developed as a robust precatalyst for Suzuki-Miyaura cross-coupling. The addition of PPh was a crucial element in the suppression of side reactions and in accelerating the cross-coupling reaction. By employing the optimal conditions, aryl-aryl, heteroaryl-aryl, and heteroaryl-heteroaryl couplings were achieved.

A Bicyclic N-Heterocyclic Carbene as a Bulky but Accessible Ligand: Application to the Copper-Catalyzed Borylations of Aryl Halides.

Imidazol-2-ylidene and imidazolin-2-ylidene are frequently employed as the core structures of N-heterocyclic carbene (NHC) ligands, because these have two nitrogen sites adjacent to carbenic carbons. The electronic and steric effects of N-substituents to a bound metal have been aptly studied, and bulky substituents have commonly been introduced on nitrogen(s). However, too much bulkiness can sometimes result in an ineffectiveness of the hindered substrates.

Higher risk of sulfonylurea-associated hypoglycemic symptoms in women with type 2 diabetes mellitus.

Background: Although some evidence suggests that women may be at greater risk for hypoglycemia, no conclusion has been reached, and female sex has not been taken into account in antidiabetic drug-induced hypoglycemia. This study aimed to determine whether females are at a higher risk of sulfonylurea (SU)-associated hypoglycemia in daily clinical practice.

Methods: The incidence of adverse reactions of SU was investigated in 2119 Japanese patients who participated in the Drug Event Monitoring project of the Japan Pharmaceutical Association, which was conducted in Kumamoto prefecture.

Safety analysis of zolpidem in elderly subjects 80 years of age or older: adverse event monitoring in Japanese subjects.

Objectives: Prescriptions of non-benzodiazepine sedative hypnotics, e.g. zolpidem, for insomnia in elderly subjects 80 years of age or older have markedly increased in the USA.

Younger females are at greater risk of vasodilation-related adverse symptoms caused by dihydropyridine calcium channel blockers: results of a study of 11,918 Japanese patients.

Background And Objective: Adequate control of blood pressure in younger females is of crucial importance, because they are at higher risk of hypertensive target organ damage compared with males of similar age. In addition, female sex is a risk factor for adverse effects of antihypertensive drugs, especially dihydropyridines. This study set out to assess the incidence of adverse reactions during dihydropyridine use in a real-life clinical setting, focusing on the influence of female sex and age.

Absence of gargling affects topical adverse symptoms caused by inhaled corticosteroids in females.

Objective: Topical adverse events caused by inhaled corticosteroids (ICS) are suspected to be more common in females. Although gargling or mouth washing after inhalation is recommended as the gold standard for preventing adverse events due to ICS, the preventive effects of this method have not been confirmed in real-world studies. This study aimed to examine the association between gargling or mouth washing and the incidence of topical adverse symptoms in males and females in daily practice.

Risk factors for adverse symptoms during dipeptidyl peptidase-IV inhibitor therapy: a questionnaire-based study carried out by the Japan Pharmaceutical Association Drug Event Monitoring project in Kumamoto Prefecture.

Background: Meta-analyses of randomized clinical trials have reported that dipeptidyl peptidase IV (DPP-4) inhibitors are well tolerated and that the incidence of hypoglycemia with the use of DPP-4 inhibitors is similar to that observed with placebos. However, in general, provider-oriented methods using medical record reviews offer lower rates of non-serious, symptomatic adverse drug reactions (ADRs) than patient-oriented methods. Moreover, severe hypoglycemia occurred in three clinical trials using sitagliptin, but in two of these trials this phenomenon has been previously described only in the drug application data in the US.

A study of the various factors that affect the properties of molecularly imprinted polymers.

We evaluated the adsorbability and selectivity of (S)-valine anilide imprinted molecularly imprinted polymer (MIP) using a batch procedure that is both independent and precise. This study revealed important information about the relationship between the performance of MIPs and experimental factors such as the components of MIP synthesis and a reaction solvent. Herein, we also describe the problems associated with the preparation of a "non-imprinted polymer," which is often used to evaluate the effect of a template molecule, and we propose a new type of reference polymer, "blank polymer.

A simple, iron-catalyzed, pyridine-assisted hydrogen peroxide epoxidation system.

A simple and inexpensive system comprised of H(2)O(2)-pyridine-FeCl(3)·6H(2)O for the catalysis of olefin epoxidation was established. Intriguingly, the reactivity of this system greatly depends on the amounts of pyridine. Various substrates, including aromatic and aliphatic olefins, were epoxidized by this simple system in moderate to excellent yields.

Aging enhances maceration-induced ultrastructural alteration of the epidermis and impairment of skin barrier function.

Background: Skin maceration is recognized as a risk factor for the development of certain skin lesions. In health care settings, incontinence-associated skin maceration is highly prevalent in the elderly. However, the effect of senescence on maceration has not been fully elucidated.

Sterically congested, "roofed" β-iminodisulfides as new chiral ligands for palladium-catalyzed, asymmetric allylic alkylation.

The preparation of a new class of "roofed" β-iminodisulfides from sterically congested, conformationally rigid chiral 2-thiazolidinones is described. A functional survey of palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with dimethyl malonate proved that symmetrical "roofed" β-iminodisulfides are efficient chiral ligands, showing enantioselectivity opposite that associated with chiral "roofed" β-iminothioether ligands.

Enantioselective aldol reaction of trimethoxysilyl enol ether catalyzed by lithium binaphtholate.

[reaction: see text] An aldol reaction of trimethoxysilyl enol ether catalyzed by lithium binaphtholate, in which water serves as an additive and plays a pivotal role in stereoselectivities, was developed. This is the first example of an aldol reaction of trimethoxysilyl enol ether catalyzed by a chiral base.