Beziehungen zwischen chemischer Verschiebung (19F und 13C) und Ladungsdichte: III

The diamagnetic and paramagnetic terms of the chemical shift are expressed by semi-empirical CNDO/II charge densities and bond orders. To establish whether a linear functional relationship exists between the calculated terms and the chemical shifts of ¹⁹F and ¹³C atoms a number of relationships in the form of a linear regression have been examined, taking into consideration both s?_dia and s?_dia plus s?_para. It was found that the relationship δ_A = a + bq_A + cQ_AB + dq_A^πQ_AB produces the smallest standard deviation.     

Highly enantioselective transfer hydrogenation of fluoroalkyl ketones

[Structure: see text] The asymmetric transfer hydrogenation of fluoroalkyl ketones mediated by [Ru(eta6-arene)((S,S)-R2NSO2DPEN)] catalysts using HCO2H-Et3N afforded the corresponding alcohols with high ee's and in excellent yields.     

Über die Bildung eines neuen,stark fluoreszierenden Heterocyclus bei der versuchten Quarterinisierung von Chinolin

When quinoline is treated with ethyl bromoacetate in ethanol at a molar ratio of 1.5:1, a highly fluorescent pyrrolodiquinolinium ion (2a) is formed along with quarternized quinoline (1a). The structure of2a has been established by infrared, proton magnetic resonance and mass spectroscopy as well as by its characteristic ultraviolet absorption spectrum.

Herrn Prof. Dr.K. Schlögl, Universität Wien, zur Vollendung des 60. Lebensjahres mit besten Wünschen gewidmet.     

Untersuchungen zur Temperaturabhängigkeit charakteristischer IR- und NMR-Absorptionen, 13. Mitt.: Zur Enolisierung von 2-substituierten Cyclohexanonen

The temperature and solvent dependence of the enolisation of 2-substituted cyclohexanones has been demonstrated by IR- and NMR-spectroscopic methods. A structure with endocyclic double bond is favorised for 2-Acetylcyclohexanone (2).     

Dielectric measurements of OH- centers in silver chloride

Dielectric measurements on silver chloride doped with hydroxyl ions show the defect is oriented in the 〈111〉 direction with a dipole moment of 1.1 debye. It reorients by a classical rate process with an activation energy of 94 cm^-1.     

Zur Chemie der Ketencarbonsäure-Derivate

Zusammenfassung Es werden an drei partiell deuterierten Systemen (Phenylmalonsäure-dianilid, 2-Amino-pyridin und Benzylmalonsäurebis-2,4,6-trichlorphenolester) weitere experimentelle Befunde erbracht, die beweisen, daß bei verschiedenen Cyclisierungsreaktionen mit reaktiven Malonsäure-derivaten intermediär Ketencarbonsäure-abkömmlinge gebildet werden.

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The chemistry of the derivatives of ketene carboxylic acid

With three partially deuterated systems (phenylmalonic dianilide, 2-aminopyridine, and 2.4.6-trichlorophenyl benzylmalonate) further experimental proof is given for the intermediate appearance of ketene carboxylic acid derivatives in cyclisation reactions with malonic acid derivatives. *** DIRECT SUPPORT *** A3615139 00011

     

Über Heterocyclen, 12. Mitt.: Zur Bromierung der 2-Oxo-6-methyltetrahydropynimidine

Zusammenfassung Die Bromierung von 2-Oxo-6-methyl- bzw. 2-Oxo-5-carbäthoxy-6-methyltetrahydropyrimidinen verläuft unter Substitution an der CH₃-Gruppe am C-6. 2-Oxo-5-carbäthoxy-6-brommethyl-bzw.-dibrommethyltetrahydropyrimidine können in 2-Oxo-6-hydroxymethyl-tetrahydropyrimidin-5-carbonsäurelactone umgewandelt werden.Im Gegensatz zu Brom reagiert Chlor mit 2-Oxo-5-carbäthoxy-6-methyltetrahydropyrimidinen unter Addition.

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Bromine reacts with 6-methyldihydropyrimidine-2-ones or 5-carbethoxy-6-methyldihydropyrimidine-2-ones to yield 6-bromomethyldihydropyrimidine-2-ones. 5-carbethoxy-6-bromomethyldihydropyrimidine-2-ones on heating split off ethyl bromide to give 6-hydroxymethyldihydropyrimidine-2-one-5-carboxylic acid lactones.Chlorine is added to the double bond of 5-carbethoxy-6-methyldihydropyrimidine-2-ones.

     

Tieffarbige Pseudooxo-Krokonsäurebisamide

4,5-Dichloro-2-dicyanomethylene-4-cyclopenten-1,3-dione (2) is synthesized by partial Retro-Michael addition of tetracyanoethylene to 4,5-dichloro-4-cyclopentene-1,3-dione. Compound2 is a new electron acceptor, withN-methyl-benzthiazolone-2-hydrazone giving a charge-transfer complex (6). Nucleophilic substitution of2 by pyrrolidine, morpholine and piperidine leads to deeply coloured bisamides7,8. With aromatic amines bisamides are formed too (11), but monosubstitution products can be isolated.N,N-Dimethylaniline reacts with2 by elimination of hydrogen chloride, leading to aN,N-dimethylaminophenyl monosubstitution product of2. The bisamides are green-blue compounds with intense violet colour in solution. The dyes can be classified as pseudooxo croconic acid bisamides, the new type of chromophore is discussed by¹³C-spectroscopy and quantum chemical calculations (CNDO-CI).

Herrn Prof. Dr.E. Ziegler zum 70. Geburtstag gewidmet.     

Synthesen von heterocyclen, 132. Mitt.: Über die Umsetzung von Di-tert.-butyl-schwefeldiimin mit Malonsäurechloriden

Zusammenfassung Di-tert.-butyl-schwefeldiimin (1) reagiert mit Malonylchlorid unter Addition zum 4-tert.-Butyl-5-chlor-7,7-dimethyl-3-oxo-5-thia-4,6-diaza-5-octensäurechlorid, welches als Dianilid2 charakterisiert worden ist. Aus1 und den Chloriden der Benzyl-, Methyl-, Äthyl- sowie Isopropylmalonsäure entstehen über die entsprechenden chlorhaltigen Zwischenprodukte durch Verlust von 2 Mol HCl Derivate des 3,5-Dioxo-1,2,6-thiadiazins3–6. Die Umsetzung von1 mit Phenylmalonylchlorid führt zum 2,5-Di-tert.-butyl-4-oxo-3-phenyl-1,2,5-thiadiazolidin-3-carbonsäurechlorid, das sich in Form des Äthylesters7 isolieren läßt. Die 3,5-Dioxo-1,2,6-thiadiazine3 und6 lagern sich bei der sauren Hydrolyse zu den Derivaten11 und12 des 1,3-Dioxoisothiazolidins um.

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Syntheses of heterocycles, CXXXII: Reaction of di-tert.-butyl-thiodiimine with malonyl chlorides

Di-tert.-butyl-thiodiimine (1) adds malonyl chloride yielding 4-tert.-butyl-5-chloro-7.7-dimethyl-3-oxo-6-thia-4.6-diaza-5-octenoyl chloride, characterized as dianilide2. The chlorides of benzyl-, methyl-, ethyl-, and isopropyl malonic acid react with1 via the corresponding intermediates with loss of 2 HCl to give derivatives of 3.5-dioxo-1.2.6-thiadiazine3–6. The reaction of1 with phenylmalonyl chloride gives 2.5-di-tert.-butyl-4-oxo-3-phenyl-1.2.5-thiadiazolidine-3-carboxyl chloride, characterized as ethyl ester7. Upon acidic hydrolysis the 3.5=dioxo-1.2.6-thiadiazines3 and6 are rearranged yielding derivatives of 1.3-dioxo-isothiazolidine (11 and12).