Über den Reaktionsmechanismus der Bildung von Melamin aus Isocyansäure

Ohne Zusammenfassung     

On the relation between classical and quantum-mechanical entropy

We discuss the problem how to define the classical entropy and prove an inequality that establishes its relation to the quantum-mechanical entropy. Furthermore we show that it is monotonic.     

14-Methyl-Derivate des morphins mit 5-, 6- oder 7gliedrigem RingC

The palladium catalyzed hydrogenation of 7,14-cyclodihydrocodeinone (1) leads to 14-methyl-C-nor-dihydrocodeinone (2 a), a starting material for the synthesis of hitherto unknown morphine and codeine derivatives. Ring expansion with diazomethane yields 14-methyl-dihydrocodeinone besides the spiro-oxiranes8 and10.

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Herrn Prof. Dr.K. Jentzsch mit den besten Wünschen zum 65. Geburtstag gewidmet.     

Beitrag zur Kenntnis des Systems La−C−N

An isothermal section at 1,200°C of the partial system La–LaN–LaC₂ was examined by X-ray and metallographic techniques. There is no evidence of an appreciable solid solubility of carbon in LaN or of nitrogen in La₂C₃ or LaC₂ at 1,200°C. There are indications however that at higher temperatures, especially that of the electric arc, the solubility of carbon in LaN might be appreciable or that a carbonitride phase of Lanthanum might exist. LaC₂ reacts with nitrogen under pressure at 1,200°C to form a new carbonitride phase with the composition La₁C_0,88N_0,77.

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Mit 2 Abbildungen     

Fluorination with xenon difluoride. Reactions of phenyl-substituted olefins in the presence of trifluoroacetic acid

Trifluoroacetic acid-catalyzed liquid-phase fluorination with xenon difluoride of phenyl-substituted olefins, e.g. cis- and trans-1-phenylpropene and cis- and trans-stilbene, results in the formation of vicinal difluorides and fluoro-trifluoroacetates. The reaction is non-stereospecific. d,1-Erythro and d,1-threo fluoro-trifluoroacetates are formed in a highly regiospecific Markovnikov manner in 50% yield. The formation of β-fluorocarbonium ions is suggested.