InclusiveK *+(890),K *+(1430) and\bar K^{ * - } (890) production inK + p interactions at 32 GeV/c

We present final results on inclusive production ofK ^*+(890),K ^*+(1430) andK ^*?(890) in \(\bar K^ + p\) interactions at 32 GeV/c, based on a statistics of ～27 events/μb. Total cross sections,p _T -andx-dependence of inclusive distributions are compared with experiments at other energies and with the Lund fragmentation model. Spin density matrix elements of theK ^*+(890) are also discussed. The results suggest that “recombination” of both initial state valence quarks \(\bar s\) andu of theK ⁺ intoK ^*+(890), responsible in the Lund model for ～45% of theK ^*+(890) cross section, is strongly suppressed.     

Neutral strange particle production inK + p interactions at 32 GeV/c

The production properties ofK _s ⁰ , \(\bar \Lambda\) andK ⁺ p interactions at 32 GeV/c are investigated using the final statistics of the experiment. We present total and semi-inclusive cross sections and aver-age multiplicities. Estimates are given of the diffractive dissociation contributions to total and differential cross sections. Thex-,p _T ^?, and transverse mass dependence of inclusive and semi-inclusive distributions is discussed as well as properties of “prompt”K _s ⁰ 's. The ratio of “prompt”K ₈₉₀ ⁺ (K ₈₉₀ ⁰ ) to “prompt”K ⁰ cross sections is measured to be 1.03±0.12 (0.98±0.17). From a comparison of \(\bar \Lambda\) production inK ^± p interactions at 32 GeV/c, we estimate a strange sea-quark suppression of 0.26 ±0.02. The double differential cross sections ofK _s ⁰ 's is studied as a function of Feynman-x andp _T ² , and a Triple-Regge fit performed. The data are compared in detail to versions of the Lund-model for low-p _T hadronic collisions.     

Nachweis von C (15)-epimeren Coleonen C und D in der Natur und ihre Bedeutung für den sterischen Verlauf der Bildung des Spirocyclopropanrings

Natural Occurrence of C(15)-Epimeric Coleons C and D and its Significance to the Stereochemistry of the Formation of a Spirocyclopropanring In a previous paper some evidence was presented for a predominant occurrence of epimeric coleons ((15S)-coleon C ((15 S)- 1a ), and (15S)-coleon D ((15S)- 2a )) in Plectranthus lanuginosus [1], The proposed structures have now been proven by careful comparison of their physical data with those of the already described C(15)-epimers whose structures were deduced by X-ray analysis of a derived cis-diketone 3 [5], Examination of the epimeric purity of coleons possessing a 2-hydroxy-1-methylethyl side-chain (coleons C , D , H , I , I ′ and derivatives) isolated from seven different species (Coleus, Plectranthus and Solenostemon) has shown that these coleons always occur as a mixture of C(15)-epimers, although in most cases with one predominant epimer. The consequences for the stereochemistry of the postulated in vivo formation of the methyl-substituted spirocyclopropane substructure is discussed.     

α-Substituierte phosphonate—38: 1-dimethylamino-1-cyano-methanphosphonsäurediethylester,ein neues edukt zur darstellung von carbonsäuren, 1-cyanoenaminen und homoenolaten

Alkylation of 1-dimethylamino-1-cyanomethanephosphonic acid diethyl ester (8), easily obtainable from diethyl phosphite and the 0,N-acetal 9, yields 1-alkyl derivatives 14. Elimination of HCN converts 14 into 1-phosphonoenamines 6. Carbonyl compounds react with 8 to give 1-cyanoenamines 15 which may be hydrolyzed to from the homologous carboxylic acid. Alternatively, deprotonation of 15 yields the homoenolate anions 17 which can be alkylated or hydroxyalkylated, permitting chain extension of carbonyl compounds through introduction of an α-carboxyl and a β-alkyl group. Acid catalyzed hydrolysis of 8 results in cleavage of the PC bond, leading to the corresponding α-dimethylamino alkanoic acids. A phosphonic acid 11 can be obtained from 8 by application of the silylester method. An unambigous assignment of E/Z-isomers of the cyanoenamines 15 has been derived from ¹³C-NMR spectroscopy.     

Photoinduzierte Cycloadditionen von 3-Benzyl-2H-azirin

Irradiation of 2-azido-3-phenyl-propene ( 5 ) in pentane or benzene solution with a high pressure lamp (pyrex filter) yields 3-benzyl-2H-azirin ( 6 ), which on further irradiation behind quartz or vycor in the presence of trifluoroacetic acid methylester or carbon dioxide yields 4-benzyl-5-methoxy-5-trifluoromethyl-3-oxazolin ( 8 ) and 4-benzyl-3-oxazolin-5-one ( 9 ), respectively (scheme 2). A small amount of 3-phenylacetonitrile is also formed.     

Der Transport von VO2 mit Cl2 und HCl + Cl2 und der Einfluß des O2-Bodenkörpergleichgewichtsdruckes auf den Transport

The Chemical Transport of VO₂ with Cl₂ and HCl + Cl₂ and the Influence of the O₂-Coexistence Equilibrium Pressure on the Transport Behaviour The transport behaviour of VO₂ with Cl₂, HCl, and Cl₂ was calculated and compared with the experimental results. VO₂ with the upper phase boundary transports with HCl and HCl + Cl₂ from the colder to the hotter zone, VO₂ of the lower phase boundary does not transport with HCl. The composition of the deposited VO₂ is near the upper boundary oxygen richer than in the start space. VO₂ does not transport with Cl₂.     

Die gravimetrische Phosphorbestimmung in wolframhaltigen St?hlen

Zusammenfassung Einige der üblichen Methoden zur Phosphorbestimmung in wolframlegierten Stählen werden unter Anwendung von ¹⁸⁵W und ³²P einer Nachprüfung unterzogen. Dabei erweisen sich die Phosphorverluste durch Adsorption an dem Wolframsäureniederschlag als gering, so daß sie bei weniger anspruchsvollen Bestimmungen unberücksichtigt bleiben können. Erheblich größer sind dagegen die Fehler, die durch Mitfällung von Wolframsäure mit dem Ammoniummolybdatophosphatniederschlag entstehen können. Es werden zwei Methoden angegeben, nach denen eine quantitative Abtrennung des Wolframs und damit eine sichere Bestimmung des Phosphors möglich ist.Herr Prof. Dr.-Ing. K. Schwabe ermöglichte es uns freundlicherweise, die Untersuchungen mit radioaktivem Wolfram und Phosphor im Zentralinstitut für Kernphysik Rossendorf, Bereich Radiochemie, durchzuführen. Ihm sei auch an dieser Stelle herzlichst gedankt.     

Singular Sturm—Liouville problems with nonnegative and indefinite weights

This article is concerned with the oscillatory properties of the eigenfunctions of a class of singular Sturm—Liouville problems—(p y)+q y=w y on (a, b), where the weight functionw vanishes on a subinterval of positive measure, or where the weight functionw changes sign on (a, b).This work was supported by the Applied Mathematical Sciences Research Program (KC-04-02) of the Office of Energy Research of the U.S. Department of Energy under Contract W-31-109-Eng-38.     

Repetierbare Ringerweiterungen durch [2,3]-sigmatropische Umlagerungen in cyclischen Allylsulfonium-allyliden; Synthese von mittleren und grossen Thiacyclen. Vorläufige Mitteilung

Repeatable ring expansions by [2,3]-sigmatropic shifts in cyclic allylsulfonium allylides; synthesis of medium- and large-sized thiacycles Allylation of a 2-vinyl thiacyclus with allyl bromide in 2,2,2-trifluoroethanol followed by ylide generation by use of aqueous potassium hydroxide results in a [2,3]-sigmatropic rearrangement with formation of a new 2-vinyl thiacyclus enlarged by three carbon atoms (Scheme 1). In this way, starting from the 5-membered ring 1 , a series of four ring enlargement sequences leads to the 17-membered thiacycles 9 and 10 via the 8-, 11- and 14-membered rings 4 , 7 and 8 (Scheme 2).     

Trennung und Identifizierung von Bactericiden auf der Basis von halogenierten Aromaten durch Dünnschicht-Chromatographie

Plates coated with silica gel with addition of fluorescence indicator are used for thin-layer chromatography with a solvent mixture of benzene and acetone (8∶2). The substances are made visible with UV-light and by spraying with solutions of 2,6-dibromoquinonechloroimide and sodium carbonate. The R_f-values, the fluorescence, and the colour of the spots allow to detect and to identify the bactericides rapidly and without further chemical techniques.