The preparation of 5‐phenacylisoxazoles and 5‐hydroxyphenyl‐isoxazoles and ‐pyrazoles by the condensation of C(<i>a</i>)‐dianions with ethyl benzoylacetate and methyl salicylate

Abstract

Abstract C(α), O ‐Dilithiooximes and C(α), N ‐Dilithiophenylhydrazones were prepared in an excess of lithium diisopropylamide (LDA). The former was condensed with ethyl benzoylacetate and methyl salicylate, and the latter condensed with methyl salicylate. The resulting precyclization intermediates were then treated with aqueous acid, which was followed by cyclodehydration to give phenacylisoxazoles and hydroxyphenyl‐isoxazoles and ‐pyrazoles.