In this paper, we report the application of the QM/QM hybrid simulation technique to the photoisomerisation reactions of anils (i.e., Schiff bases of salicylaldehyde with aniline derivatives) in the solid state, on the example of the photochromic polymorph of N-salicylidene-2-chloroaniline. By propagating molecular dynamics on a potential energy surface constructed using a combination of time-d...

Little is known about the distribution of prostaglandin E? (PGE?) and prostacyclin (PGLJ production in the canine kidney. To determine the basal and stimulated profiles of PGE^ and PGI2 production along the corticomedullary axis of the dog kidney, a slice (0.5 mm thick, 10-50 mg) was obtained from six equally spaced zones along the axis (zone 1, medullary crest; zones 2 and 3, inner medulla; zo...

Ultrafast processes in photoexcited N-salicylideneaniline have been investigated with femtosecond time-resolved resonance-enhanced multiphoton ionization spectroscopy. The ion signals via the S(1)(n,pi( *)) state of the enol form as well as the proton-transferred cis-keto form emerge within a few hundred femtoseconds after photoexcitation to the first S(1)(pi,pi( *)) state of the enol form. Thi...

To investigate the effects of antiinflammatory steroids on in vivo prostaglandin production, urinary excretion rates of six different cyclo-oxygenase products were determined before, during, and after the administration of dexamethasone (1 mg/kg per d). Urine was collected in metabolism cages and was analyzed for prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha) by radioimmunoassay after ope...

The relationship between the release of histamine, a major mast cell mediator of conjunctival type I reactions, and the production of a prostanoid, prostacyclin (prostaglandin I2, PGI2), was examined in a guinea pig model of allergic conjunctivitis. Guinea pigs were sensitized topically and challenged by repeated conjunctival instillation of fluoresceinyl ovalbumin. Histamine and 6-keto-PGF1 al...

Mechanisms of double carbonylation reactions catalyzed by palladium complexs to give a-keto amides and a-keto esters, stoichiometric double carbonylation of ally1 carbonates, and cyclization carbonylation . of 3-butenoic acid to give cyclic anhydrides are discussed as combination of elementary processes of organometallic reactions.

In the title compound C(14)H(17)N(3)O(2), the dihedral angle between the rings is 16.68 (13)°. Although the compound crystallizes in the keto form, the possibility of keto-enamine-enol-imine tautomerism is explained by a strong intra-molecular N-H⋯O hydrogen bond.

The different reactivity of two kinds of carbonyl groups in keto aldehyde substrates has been exploited for the synthesis of phenanthrols, naphthols, and their heteroatom-containing analogues. Key to this highly efficient and robust methodology is the catalyst-free intramolecular formal diazo carbon insertion of N-tosylhydrazones into keto C-C bonds.

Smokers or people undergoing nicotine replacement therapy excrete approximately 10% of the nicotine dose as 4-oxo-4-(3-pyridyl)butanoic acid (keto acid) and 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid). Previously, these acids were thought to arise by secondary metabolism of the major nicotine metabolite cotinine, but our data did not support this mechanism. Therefore, we hypothesized th...

In nine strains of Clostridium innocuum, 3 beta-hydroxysteroid-dehydrogenating activities were detected. 3 beta, 7 alpha, 12 alpha-Trihydroxy- and 3 beta-hydroxy-12-keto-5 beta-cholanoic acids were identified as reduction products of the respective 3-keto bile acids by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry. One strain was shown to contain a NAD-dependent 3 be...