Notiz über Parachloraldehyd

Ohne Zusammenfassung     

On Super-KMS functionals and entire cyclic cohomology

We formulate the super-KMS condition suggested by Connes and Kastler, in the context of entire cyclic cohomology of quantum algebras. We show that the Chern character of Jaffe, Lesniewski, and Osterwalder — associated by Kastler to a super-KMS functional — satisfies the entire growth condition. Hence, a super-KMS functional defines a cocycle for the entire cyclic cohomology of quantum algebras.Supported in part by the National Science Foundation.     

Stereoelectronic control of exo/endo rate ratios in the solvolysis of 2-norbornyl p-toluenesulfonates

The variable exo/endo rate ratios observed in the solvolysis of 6-exo-substituted exo- and endo-2-norbornyl p-toluenesulfonates are due to differential transmission of polar effects in the transition state for ionization.     

GC Method for Determining Polyadipate Plasticizers in Foods: Transesterification to Dibutyl Adipate, Conversion to Migrating Polyadipate

The determination of the migration of polyadipates (plasticizers in PVC) into foods or food simulants for compliance testing involves three principal steps. (1) Adipate from the polyadipate material in the food or simulant is measured through transesterification to the butyl esters directly in the homogenated food, which presupposes tight control of the kinetics. Butyl esters are more easily extracted, and the butanol used for transesterification also serves as principal extraction solvent. (2) To check compliance with the specific migration limit, adipate is determined in the material of a molecular mass below 1,000 Da, which involves preparative preseparation by size exclusion chromatography followed by transesterification. (3) The migrated polyadipate material is calculated from the adipate measured by a conversion factor determined from the qualitative and quantitative analysis of the polyadipate components <1,000 Da.     

Reactions of lithiated 2,5-dimethylazaferrocene with selected electrophiles

Lithiation of 2,5-dimethylazaferrocene 1 with sec-BuLi/TMEDA in THF at −78 °C proceeds (as shown by quenching with D₂O) to comparable extent on the methyl groups and the Cp ring. However, the outcome of the reaction of the lithiated 1 with an electrophile depends on the nature of this electrophile. In the reaction with 4-methoxybenzaldehyde only the product originated from the lateral lithiation is formed, whereas the reaction with 4-methoxyacetophenone and 4,4′-dimethoxybenzophenone afforded mixtures of the products resulting from lateral and ring-lithiation. Similar results were also obtained in the reaction of lithiated 1 with chlorodiphenylphosphine and diphenyl diselenide. On the other hand, the exclusive formation of the Cp-substituted product was observed in the reaction of lithiated 1 with N,N-dimethylformamide. The structures of selected products (oily compounds were transformed into the corresponding crystalline W(CO)₅-complexes) were confirmed by X-ray diffraction. The presented reactions open a novel entry to specifically substituted azaferrocenes (especially those containing heteroatom substituents) with potential applications as ligands for the homogenous catalysis.