A self-condensation cyclization reaction mediated by phosphorus pentoxide (P2O5) and catalyzed by zinc bromide (ZnBr2) is presented for the synthesis of polysubstituted 4-pyridones and 2-pyridones from β-keto amides. A variety of β-keto amides are used in this approach, and a wide range of functionalized 4-pyridones and 2-pyridones were obtained in good to excellent yields. When employing the N...

We have examined the effect of activated neutrophils on the release of prostacyclin (PGI2) from cultured endothelial cells by radioimmunoassay and thin layer chromatography of its stable metabolite, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). Phorbol myristate acetate-activated neutrophils induced a time- and dose-dependent release of 6-keto-PGF1 alpha from human and bovine endothelial c...

Although biochemical studies have been made of the cY-keto analogues of a number of a-amino acids, the cr-keto analogues of isoleucine have received relatively little attention. Two cY-keto analogues of this amino acid are possible, namely d-a-keto-p-methylvaleric acid, which has the same configuration at the P-carbon atom as L-isoleucine and n-alloisoleutine, and Z-a-keto-p-methylvaleric acid,...

We aimed to investigate the application of combined mechanistic pharmacokinetic (PK) and pharmacodynamic (PD) modeling and simulation in predicting the domperidone (DOM) triggered pseudo-electrocardiogram modification in the presence of a CYP3A inhibitor, ketoconazole (KETO), using in vitro-in vivo extrapolation. In vitro metabolic and inhibitory data were incorporated into physiologically base...

Walnut consumption produces beneficial cardiovascular effects. The aim of the present study is to compare the effects of meat enriched in walnut paste (WM) and low-fat meat (LM) consumptions on platelet aggregation, plasma thromboxane A2 (TXA2, measured as TXB2), prostacyclin I2 (PGI2, as 6-keto-PGF1alpha) and the thrombogenic ratio (TXB2/6-keto-PGF1alpha) in volunteers at high CVD risk. Twenty...

We investigated the effects of prostaglandins (PG) E2, PGD2, PGI2, and its metabolites 6-keto-PGE1 and 6-keto-PGF1 alpha, and U46619 (stable analogue of the PG endoperoxide, PGH2) administered either intravitreally or topically on intraocular pressure (IOP), pupil diameter, aqueous protein, and the entry of polymorphonuclear cells (PMNs) in the aqueous. PGE2, 6-keto-PGE1, U46619, and PGI2 incre...

Aldo-keto reductase family 1 member C3 has recently been regarded as a potential therapeutic target in castrate-resistant prostate cancer. Herein, we investigated whether berberine delayed the progression of castrate-resistant prostate cancer by reducing androgen synthesis through the inhibition of Aldo-keto reductase family 1 member C3. Cell viability and cellular testosterone content were mea...

Relative bioefficacy and toxicity of Met precursor compounds were investigated in young chicks. The effectiveness of DL-Met and 2-keto-4-(methylthio)butyric acid (Keto-Met) to serve as L-Met precursors was quantified using Met-deficient diets of differing composition. Efficacy was based on slope-ratio and standard-curve methodology. Using L-Met as a standard Met source added to a purified diet,...

keto-enol tautomerism was investigated for ionized pyruvic acid using the dft(b3lyp) method and the larger basis sets [6-31++g(d,p), 6-311++g(3df, 3pd) and aug-cc-pvdz]. change of the tautomeric preference was observed when going from the neutral to ionized tautomeric mixture. ionization favors the enolization process (ketoenol) of pyruvic acid, whereas the ketonization (ketoenol) is preferred ...

The intestinal worm, Ascaris lumbricoides, ferments carbohydrate to a mixture of end products, of which the two major ones are Z-methylbutyrate and 2-methylvalerate. The mode of formation of branched chain acids with a methyl group at C-2 or other even numbered carbon atoms is still not completely understood. It has been proposed that these compounds could be formed either from the fatty acid s...