Cereulide synthetase is a two-protein nonribosomal peptide synthetase system that produces a potent emetic toxin in virulent strains of Bacillus cereus. The toxin cereulide is a depsipeptide, as it consists of alternating aminoacyl and hydroxyacyl residues. The hydroxyacyl residues are derived from keto acid substrates, which cereulide synthetase selects and stereospecifically reduces with imbe...

A new series of substituted 8-fluro-4H-pyrimido[2,1-b] [1,3]benzothiazole-4-ones () substituted 7-methyl-4H-isoxazolo[2,3-a]pyrimidin-4-ones, and substituted 2-methyl-5,6,7,8-tetrahydro-9H-isoxazolo[2,3-a]pyridopyrimidin-9-ones, compounds I-VII, have been prepared via condensation of beta-keto esters with 2-aminopyridine derivatives, in the presence of polyphosphoric acid. The same technique ha...

deprotection of phosphate, phosphate, and sulfite esters by silica chloride is described. silica chloride is a mild, selective, and effective reagent for cleavage of benzyl and t-butyl esters of the above compounds.

The title compound, C(15)H(19)NO(5), is bent with a dihedral angle of 61.8 (2)° between the mean planes of the benzene ring and a group encompassing the ester functionality (O=C-O-C). The dihedral angle of 0.8 (2)° between the mean planes of the nitro group and the benzene ring indicates near coplanarity. In the crystal, each mol-ecule is linked to four adjacent mol-ecules by weak C-H⋯O hydroge...

The combination of gold(I) and enzyme catalysis has provided access to a series nor(pseudo)ephedrine derivatives in regio- stereoselective manner. approach involves developing IPrAuNTf2-catalyzed hydration 1-phenylprop-2-yn-1-yl acetate or N-(1-phenylprop-2-yn-1-yl)acetamide, followed by (dynamic) asymmetric biotransamination bioreduction the corresponding keto ester amide intermediates. Enzyme...

Acetylcholine (ACh) can effect vasodilation by several mechanisms, including activation of endothelial nitric oxide (NO) synthase and prostaglandin (PG) production. In human skin, exogenous ACh increases both skin blood flow (SkBF) and bioavailable NO levels, but the relative increase is much greater in SkBF than NO. This led us to speculate ACh may dilate cutaneous blood vessels through PGs, a...

Lead tetra acetate (Pb(IV) or LTA) oxidation of the esters X —C,,H4—C H(OH ) — COO CH, (X = H, m-NO: , p-N O : , /?;-Cl. /?-Cl. p-Br. p-CH, and p-C:H s) gives corresponding keto esters. The reaction is first order in [Pb(IV)] and second order in [Ester], and is catalysed by pyridine and 2,6-lutidine. The pyridine catalysed reaction is first order each in [Pb(IV)]. [Ester] and [Pyridine]. A kine...

McCord, Gregg R., Jean-Luc Cracowski, and Christopher T. Minson. Prostanoids contribute to cutaneous active vasodilation in humans. Am J Physiol Regul Integr Comp Physiol 291: R596–R602, 2006. First published February 16, 2006; doi:10.1152/ajpregu.00710.2005.— The specific mechanisms by which skin blood flow increases in response to a rise in core body temperature via cutaneous active vasodilat...