4-Aminophenol → 4-Aminophenoxy-4'-phenylethynylbenzophenone

Beteiligte Stoffe

Reaktionsschritte

The phenylethynyl group has two important advantages over the ethynyl group. These are stability towards conditions of aromatic nucleophilic displacement reactions and stability at moderate temperatures (i.e. 150-250° C.). For example, when 4-phenylethynyl-4'-fluorobenzophenone was treated with a slight excess of 3 or 4-aminophenol in the presence of an alkali metal base such as potassium carbonate in a polar aprotic solvent such as N,N-dimethylacetamide (DMAc) at 143° C., 3 or 4-aminophenoxy-4'-phenylethynylbenzophenone was afforded in nearly quantitative yield. However, several attempts to make the 3-aminophenoxy-4'-ethynylbenzophenone from the 4-ethynyl-4'-fluorobenzophenone under similar reaction conditions afforded a mixture of products. In addition, imide model compounds of the phenylethynyl endcapper react at a moderate to fast rate in air at 300° to 350° C. whereas analogous model compounds containing the ethynyl group react at a moderate to fast rate in air at 200° to 250° C. Phenylethynyl containing imide model compounds are reasonably stable at 200° C. (see Example 6) whereas thynyl containing imide model compounds react at 200° C.

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