Biing-Jiun Uang

Catalytic enantioselective coupling of 2-naphthols by new chiral oxovanadium complexes bearing a self accelerating functional group

New chiral oxovanadium complexes containing an extra phenolic hydroxyl group were found to enhance the catalytic enantioselective coupling of 2-naphthols in moderate to good enantioselectivity.

Asymmetric Addition of Dimethylzinc to α-Ketoesters Catalyzed by (−)-MITH

This investigation describes the catalytic asymmetric addition of dimethylzinc to alpha-ketoesters in the presence of (-)-MITH ( 5) and triethyl borate as an additive to give the corresponding chiral alpha-hydroxy esters with good yields and high enantioselectivities.

Enantioselective addition of diethylzinc to aldehydes induced by a new chiral Ti(IV) catalyst

Abstract A new chiral titanium reagent, derived from optically active trans -1,2-dicamphorsulfonamidocyclohexane 2a and Ti(O i Pr) 4 , was found to promote the enantioselective addition of diethylzinc to various aldehydes giving rise to the corresponding alcohols in high yields with moderate to high selectivity.

Antidiabetic Effects of Pterosin A, a Small-Molecular-Weight Natural Product, on Diabetic Mouse Models

The therapeutic effect of pterosin A, a small-molecular-weight natural product, on diabetes was investigated. Pterosin A, administered orally for 4 weeks, effectively improved hyperglycemia and glucose intolerance in streptozotocin, high-fat diet–fed, and db/db diabetic mice. There were no adverse effects in normal or diabetic mice treated with pterosin A for 4 weeks. Pterosin A significantly reversed the increased serum insulin and insulin resistance (IR) in dexamethasone-IR mice and in db/db mice. Pterosin A significantly reversed the reduced muscle GLUT-4 translocation and the increased liver phosphoenolpyruvate carboxyl kinase (PEPCK) expression in diabetic mice. Pterosin A also significantly reversed the decreased phosphorylations of AMP-activated protein kinase (AMPK) and Akt in muscles of diabetic mice. The decreased AMPK phosphorylation and increased p38 phosphorylation in livers of db/db mice were effectively reversed by pterosin A. Pterosin A enhanced glucose uptake and AMPK phosphorylation in cultured human muscle cells. In cultured liver cells, pterosin A inhibited inducer-enhanced PEPCK expression, triggered the phosphorylations of AMPK, acetyl CoA carboxylase, and glycogen synthase kinase-3, decreased glycogen synthase phosphorylation, and increased the intracellular glycogen level. These findings indicate that pterosin A may be a potential therapeutic option for diabetes.

Asymmetric epoxidation of allylic alcohols catalyzed by new chiral vanadium(V) complexes

Vanadium catalysts bearing (+)-ketopinic acid-based chiral hydroxamic acids as constituent ligands are investigated in the asymmetric epoxidation of allylic alcohols. Chiral ligands lacking an N-substituent and those having a bulkier aryl group in the bornane skeleton provided better selectivity.

Hydroxychavicol, a novel betel leaf component, inhibits platelet aggregation by suppression of cyclooxygenase, thromboxane production and calcium mobilization

Platelet hyperactivity is important in the pathogenesis of cardiovascular diseases. Betel leaf (PBL) is consumed by 200‐600 million betel quid chewers in the world. Hydroxychavicol (HC), a betel leaf component, was tested for its antiplatelet effect.

Recent advances in the oxovanadium mediated biaryl coupling and modified Mannich-type reaction

Abstract Vanadium induced organic synthesis has gained significant importance in recent years. In this proceeding, we have discussed the recent advances in vanadium mediated biaryl coupling and some CC bond formation reactions. Efficacy of the vanadium in various oxidative coupling reactions of phenols, naphthols, their methyl ethers and in the asymmetric synthesis of chiral BINOLs is discussed in this review. Vanadium catalysed modified Mannich reaction is also discussed.

Identification, SAR studies, and X-ray co-crystallographic analysis of a novel furanopyrimidine aurora kinase A inhibitor

Herein we reveal a simple method for the identification of novel Aurora kinase A inhibitors through substructure searching of an in‐house compound library to select compounds for testing. A hydrazone fragment conferring Aurora kinase activity and heterocyclic rings most frequently reported in kinase inhibitors were used as substructure queries to filter the in‐house compound library collection prior to testing. Five new series of Aurora kinase inhibitors were identified through this strategy, with IC50 values ranging from ∼300 nM to ∼15 μM, by testing only 133 compounds from a database of ∼125 000 compounds. Structure–activity relationship studies and X‐ray co‐crystallographic analysis of the most potent compound, a furanopyrimidine derivative with an IC50 value of 309 nM toward Aurora kinase A, were carried out. The knowledge gained through these studies could help in the future design of potent Aurora kinase inhibitors.

Design and Synthesis of α-Ketoamides as Cathepsin S Inhibitors with Potential Applications against Tumor Invasion and Angiogenesis

A series of small molecules bearing an alpha-ketoamide warhead were synthesized and evaluated for their ability to inhibit cathepsin S, a key proteolytic enzyme upregulated in many cancers during tumor progression and metastasis. Most of the synthetic compounds were noncytotoxic, but several robustly inhibited cathepsin S (IC(50) < 10 nM) and potently suppressed cell migration, invasion, and capillary tube formation. These results highlight the potential of alpha-ketoamide therapy for preventing or delaying cancer spread.

Enantioselective borane reduction of aromatic ketones using chiral BINOL derivatives as ligands in an aluminum catalyst

Abstract Chiral aluminum complex-catalyzed asymmetric borane reduction of aromatic ketones has been successfully carried out in the presence of ( R )-BINOL derivatives as ligands. Secondary alcohols were obtained in high yields with good enantioselectivities (up to 90% e.e.).