Gekreuzt konjugierte oligomere aus pyrrol-, benzol- und carbonyl-Bausteinen

Abstract Chalcones can serve as C 2 or C 3 components for the formation of 1 H -pyrroles. In particular the reaction with tosylisocyanid could be applied to the oligochalcones 2d - g with up to 6 enone units. A series of cross-conjugated oligomers 8d - g was obtained; these compounds consist of a chain of 1,4-phenylene, carbonyl and 1 H -pyrrole-3,4-diyl building blocks. The benzene rings bear two propoxy sidechains in order to enhance the solubility.

Oligo(1,4-phenylenepyrazole-3,5-diyl)s

The bifunctional nucleophile methylhydrazine reacts in an alkaline medium in a regioselective mode with chalcones to yield 2-pyrazolines, which can be oxidized by DDQ to the corresponding 1H-pyrazoles. From oligo(chalcone)s this reaction yields cross-conjugated compounds with an alternating sequence of 1,4-disubstituted benzene rings and 3,5-disubstituted 1H-pyrazole rings. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthese und Kristallstrukturanalyse eines 2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepins / Synthesis and Crystal Structure Analysis of a 2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepine

Abstract The enone unit of chalcones is a synthetically valuable substructure for the formation of heterocycles. Whereas propoxy groups as solubilizing side chains on the phenyl groups do not much affect the generation of pyrazole and pyridine rings, they reduce significantly the yield of the diazepine ring system 4. We attribute this effect to the large twist angles between the ring planes, which are demonstrated by a crystal structure analysis.

Synthese von Oligo(p-phenylen-m-pyridindiyl)en