4-Pyridones from 1,3,5-triketones

Pyridones from 1,3,5 triketones, 46,60 Pyrolysis, diketene to ketene, 46, SO a-PYRONE, 46,101 in Diels Alder reactions, 46, 104 4-Pyrones, 2,6 disubstituted, from 1,3,5 pentanetnones by acid cycliza tion, 46, 61... 

Hauser and co-workers have prepared a number of triketones by (1) acylation of benzoylacetone with aliphatic esters employing lithium amide, (2) by twofold aroylation of acetone with methyl esters using sodium hydride, (3) by aroylation and acylation of aliphatic diketones with potassium amide in liquid ammonia and (4) by aroylation of sodioacetoacetaldehyde in the presence of potassium amide. Disodio- and dipotassiobenzoylacetone are not acylated by ethyl acetate or by phenyl propionate. However, dilithiobenzoylacetone and dilithioacetylacetone with an excess of lithium amide are acylated by aliphatic esters. It is usually more convenient to synthesize 4-pyridones directly from these triketones by cyclization with ethanolic ammonia rather than by way of the intermediate Qpyrone. ... 

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