Diastereoselektivität der Geruchswahrnehmung von Alkoholen der Iononreihe

Diastereoselective Odor Perception of Alcohols in the Ionone Series The characteristic odor of the diastereoisomers 1 and 2 of 1-(2,2,6-trimethylcyclohexyl)-3-hexanol is configuration dependent, the trans-alcohol 1 being identified as the sensorily active component. Structure modification of model 1 / 2 , for example substitution on C(2), C(13), and C(14) (ionon numbering) by CH₃ groups, introduction of double bonds in the 3- or 4-position, and isosteric substitution of C(7) by an O-atom, leads to analogues revealing an unequivocal relation between stereochemistry and odor. The specific odor of alcohol 1 is generally released when all substituents are in an equatorial position; the resulting analogy with the molecular size and shape of odoriferous steroids suggests that the release of the particular scent can be correlated with a steroid-resembling receptor event.     

Favorskii-Reaktion von enolisierbaren Cyclobutanonen: Abhängigkeit der Stereoselektivität von der Abgangsgruppe,der Temperatur und dem Lösungsmittel

Dependence of the Stereoselectivity on the Leaving Group, the Temperature and the Solvent in the Favorskii-Reaction of Enolisable Cyclobutanones The base-induced contraction of enolisable 2-halocyclobutanones is often not stereoselectiv. The cis/trans-isomer ratio in the cyclopropanecarboxylic acid 9 derived from 2,4-cis-substituted cyclobutanones 7 depends on the nature of the leaving group. In addition, the choice of the base, the temperature and the solvent can profoundly affect the stereoselectivity of the Favorskii-reaction. The use of the p-bromophenylsulphonyloxy group as leaving group and an inhomogenous reaction medium leads exclusively to cis-carboxylic acid 9 .     

Modellberechnung der EMK und der Ionenselektivität von Membranelektroden-Messketten

Based upon a set of clearly specified assumptions, a universal integral equation is derived which describes the steady-state EMF of an electrochemical cell containing any type of ion-selective membrane electrode. The various modes of delineating the phenomenon ion-selectivity by an explicit function are shown. For all types of analytically important ion-sensitive electrodes, the selectivity between monovalent cations and anions, respectively, can be neatly and comprehensively rationalized. These theoretically derivable expressions are compiled.     

Oxydation von nichtcyclischen Derivaten der Methylarsonigsäure

Oxidation of Noncyclic Derivatives of Methylarsonous Acid Reaction of methyldichloroarsine with alcohols and sec. amides yields esters, diamides and amidechlorides of methylarsonous acid. Oxidation with o-chloranil yields the corresponding derivatives of methylarsonic acid.     

Stabilitätskonstanten der Kupferkomplexe von Acetessigsäureamiden. I

The stability constants of the copper complexes of acetoacetdialkylamides and substituted acetoacetanilides have been determined by potentiometric pH-measurements. The variation of stability constants with phenyl substituents is interpreted.     

Synthese von phenoxygruppenhaltigen Derivaten der Methandiphosphonsäure

Synthesis of Phenoxy Derivatives of Methanediphosphonic Acid Derivatives of the methanediphosphonic acid containing different numbers of phenoxy groups were prepared by Michaelis-Arbusov reaction of iodomethane phosphonic acid esters with phosphorous acid esters and by reaction of methane diphosphonic acid tetrachlorid with sodium phenolate. The obtained products were investigated by means of n.m.r. spectroscopy.