Palladium (II) coordination complexes catalyze the reaction of alcohols with ketones to yield ethers. During the catalytic cycle, the alcohol adds selectively to the β-carbon (anti-Markovnikov). In this work, mechanism and kinetics for the reaction of methanol with methyl vinyl ketone (MVK), being catalyzed by Pd, has been theoretically investigated in detail. Using quantum mechanical approach,...

We synthesized two series of androstane derivatives as inhibitors of type 3 and type 5 17β-hydroxysteroid dehydrogenases (17β-HSDs). In the first series, four monospiro derivatives at position C17 were prepared from androsterone (ADT) or epi-ADT. After the protection of the alcohol at C3, the C17-ketone was alkylated with the lithium acetylide of tetrahydro-2-(but-3-ynyl)-2-H-pyran, the triple ...

We examined whether nitric oxide (NO) inhibits prostanoid synthesis through actions on cyclooxygenase (COX) gene expression and activity. Bovine pulmonary artery endothelial cells were pretreated for 30 min with the NO donors 1 mM S-nitroso-N-acetylpenicillamine (SNAP), 0.5 mM sodium nitroprusside (SNP), or 0.2 microM spermine NONOate; controls included cells pretreated with either 1 mM N-acety...

Bis-dehydroxycurcumin tert-butyl ester (K2T23) is a derivative of the natural spice curcumin. Curcumin is widely studied for its multiple therapeutic properties, including photosensitized cytotoxicity. However, the full exploitation of curcumin phototoxic potential is hindered by the extreme instability of its excited state, caused by very efficient non radiative decay by means of transfer of t...

In alginate-assimilating bacteria, alginate is depolymerized to unsaturated monosaccharide by the actions of endolytic and exolytic alginate lyases (EC 4.2.2.3 and EC 4.2.2.11). The monosaccharide is non-enzymatically converted to 4-deoxy-L-ery thro-5-hexoseulose uronic acid (DEH), then reduced to 2-keto-3-deoxy-D-gluconate (KDG) by a specific reductase, and metabolized through the Entner-Doudo...

β-keto esters are used as precursors for the synthesis of β-amino acids, which are building blocks for some classes of pharmaceuticals. Here we describe the comparison of screening procedures for hydrolases to be used for the hydrolysis of β-keto esters, the first step in the preparation of β-amino acids. Two of the tested high throughput screening (HTS) assays depend on coupled enzymatic react...

2-Octyl gamma-bromoacetoacetate (O gamma Br), an endogenous compound originally isolated from human cerebrospinal fluid (CSF), has previously been demonstrated to increase REM sleep duration in cats. Based on the chemical structure of O gamma Br and its reported sleep-inducing effects, we synthesized O gamma Br along with chemically related analogs and tested these compounds as inhibitors of fa...

Vancomycin resistance in Enterococcus faecium BM4147 is mediated by vancomycin resistance proteins VanA and VanH. VanA is a D-alanine:D-alanine ligase of altered substrate specificity [Bugg, T. D. H., Dutka-Malen, S., Arthur, M., Courvalin, P., & Walsh, C. T. (1991) Biochemistry 30, 2017-2021], while the sequence of VanH is related to those of alpha-keto acid dehydrogenases [Arthur, M., Molinas...

Using Hartree–Fock (HF) and ِِDensity Functional Theory (DFT) calculations the thermodynamic properties such as thermal energy , , thermal enthalpy , , thermal entropy , , thermal Gibbs free energy , , heat capacity ,Cv, and molecular structures of several species involving in keto↔enol tautomerism related to acetaldehyde (A), 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and  acetylacetone (AA) h...