Diffraction of a low energy (<4 eV) carbon-K-photoelectron wave that is created inside a CO molecule by absorption of a circularly polarized photon is investigated. The measurements resolve the vibrational states of the K-shell ionized CO+ molecule and display the photoelectron diffraction patterns in the molecular frame. These show significant variation for the different vibrational states. This effect is stronger than predicted by state-of-the-art theory. As this study is performed close to C-K-threshold and, therefore, far below the molecule's sigma-shape resonance, this surprisingly strong effect is not related to that resonance phenomenon.

The structure of the urinary metabolites formed after moclobemide administration in humans was elucidated, and the pattern compared with that in the plasma. The metabolic pathways of moclobemide were also compared with those of structurally related substances. After oral moclobemide administration, on average 95% of the dose was recovered in the urine within 4 days, with a mean of 92% being excreted during the first 12 h. The drug is extensively metabolized: less than 1 % of the dose was excreted unchanged. A total of 19 metabolites, accounting together for about 64% of the dose, was isolated and all metabolites accounting for more than 170 of the dose were identified. Consistent with other morpholinecontaining compounds, metabolic pathways of moclobemide include mainly oxidative attack on the morpholine moiety, leading to a multitude of oxidation products. Four primary metabolic reactions were identified: morpholine N-oxidation, aromatic hydroxylation, morpholine C-oxidation and deamination. The major metabolites in urine are 4 carboxylic acids (M7A and M7B, M8, M9) that account for 49% of the dose. Only 2 metabolites (M3, MlO) were found to be hydroxylated on the aromatic nucleus. They were excreted completely as conjugates of glucuronic and/ or sulfuric acid. Conjugation in general, however, seems to be of minor importance in the overall biotransformation of the drug. The metabolite pattern in plasma was found to be qualitatively but not quantitatively similar to that observed in urine. Almost all of the main urinary metabolites were found in plasma as well. The unchanged parent compound and 2 primary oxidation products of the morpholine ring (Ml, MlS), which were present in urine only in trace amounts, could easily be detected in I plasma.Moclobemide belongs to a new generation of monoamine oxidase (MAO) inhibitors of the benzamide type and contains a morpholine ring as a characteristic part of its structure.The aim of this study was to elucidate the structures of the urinary metabolites formed from moclobemide after its administration to humans and to compare the metabolite pattern in urine and plasma. In addition, a comparison of metabolic pathways between moclobemide and structurally related drugs was attempted. Material and methods Drug administration and sample collectionTwo healthy young volunteers received 50 mg 14Clabelled moclobemide (2 pCi/mg; position of radiolabel, see Fig. 1) orally in a hard gelatine capsule. Blood was taken by puncture of an arm vein at different time points up to 10 h after administration and plasma was obtained by centrifugation.Urine and faeces were collected quantitatively in fractions up to 96 h after administration. Isolating and identifying the metabolitesMetabolites were isolated from pooled 0-12 h urine by chromatography on Amberlite XAD-2 resin and subsequent extractions with ethyl acetate at pH 9 and pH 3. These extractions were made before and after enzymatic hydrolysis with a mixture of beta-glucuronidase and arylsulfatase. Separation and purification of the metabo...

We have measured the angular distribution of Carbon K-Auger electrons from fixed in space, core-ionized, CO molecules in coincidence with the kinetic energy release of the C + and O + fragments . We find a very narrow ejection of Auger electrons in the direction of the oxygen and an oscillatory diffraction pattern. Even for similar electron energies, the angular distribution strongly depends on the symmetry of the final state. Our results do not support an earlier study (Guillemin et al [1]) which claimed observation of a breakdown of the two-step model of Auger and photoelectron emission.The study of Auger decay from molecules still pursues many open questions. One of the challenges results from the number and complexity of the final states. The many very broad overlapping structures in the Auger energy distribution often do not allow for a clear assignment of the decay channel [2]. A second challenge results from the interaction of the Auger electron with the molecular potential. Similar to photoelectrons [3,4] the Auger electron will be multiply scattered in the molecule hence modifying Auger rates and angular distributions. A third challenge was posed recently by the claim [1] that even off-resonance the creation of a core hole by photo-ionization and its subsequent Auger decay cannot be treated as two independent steps (two-step model), as has been commonly assumed [3,5].In the present letter we address these three challenges by reporting an experiment on the Auger decay of carbon K-shell ionized CO + . We have measured the Auger electron energy and angle in coincidence with the energy and angle of both fragment ions of the CO 2+ . Such complete monitoring of the process results in a qualitatively new level of insight into the molecular Auger decay. First the high resolution in electron energy and kinetic energy release (KER) allows determination of the final electronic states of the C + and O + fragments which in turn helps to identify the molecular decay channel. Second and more importantly, the measurement of the direction of fragmentation often, a posteriori, determines the molecular axis at the instant of Auger emission. We therefore obtain Auger electron angular distributions in * Electronic address: doerner@hsb.uni-frankfurt.de the molecular frame. These have, as we show below, a very rich structure. It has been emphasized from the theory side that the angular distributions from fixed in space molecules are a key to deeper understanding of the molecular Auger process [3,7,8]. Zähringer et al. have shown that the Auger electron angular distribution can be understood as resulting from two processes acting together. The symmetry of the molecular states involved and their nonspherical electron density lead to a coarse structure. On top of this a diffraction pattern from the interaction of the Auger electron wave with the molecular potential has been seen in the calculations. None of these effects have been observed experimentally until now [1,9].The experiment was performed at Bl 4.0 [10] of the Advanc...

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6-Deoxy-6-chloro-, -6-bromo-, -6-iodo-and -6-fluoro derivatives of L-ascorbic acid have been synthesized and characterized. The physiological properties of the chloro derivative have been investigated. It shows a high antiscurvy activity.The chloro-and bromo-derivatives have been reduced to the corresponding deoxy compound, which is an interesting chiral intermediate for the preparation of rare o-deoxy sugars.Trotz ausgiebiger Arbeiten auf dem Gebiet der L-Ascorbinsaure-Chemie [ 1-81 wurden ihre 6-Desoxy-6-halogen-Derivate bisher noch nicht hergestellt. Demzufolge blieb ihre physiologische Aktivitat bis heute unbekanntzusammen mit ihren sonstigen (2. B. praparativen) Verwendungsmoglichkeiten. Wir berichten hier uber die Herstellung aller vier 6-Desoxy-6-halogen-~-ascorbinsauren.6-Desoxy-6-chlor-~-ascorbinsaure (3) wurde zunachst als Nebenprodukt bei der salzsauren Hydrolyse von 2,3; 4,6-Di-O-isopropyliden-~-gulosonsaure (1) zu L-AScorbinsaure (2) isoliert. Spater wurde festgestellt, dass L-Ascorbinsaure selbst unter ahnlichen Bedingungen in massig guter Ausbeute in 6-Desoxy-6-chlor-~-ascorbinsaure ubergefiuhrt werden kann.Da die Herstellung der anderen 6-Desoxy-6-halogen-~-ascorbinsauren (Fluorund Jod-Derivate) auf analoge Weise nicht gelingt, wurde eine fur alle Halogenderivate geeignete Synthese ausgearbeitet.Als Ausgangsmaterial diente ebenfalls die 2,3 ; 4,6-Di-O-isopropyliden-~-gulosonsaure (1) [4]; nach Veresterung wurde sie durch selektive Hydrolyse [9] in den 2,3-O-Isopropyliden-~-gulosonsauremethylester (5) ubergefuhrt, der als Schlussel-0018-019X/80/6/1728-12$01.00/0 0 1980 Schweizerische Chemische Gesellschaft