Expeditive Access to 2-Substituted 4 H -Pyrido[1,3]oxazin-4-ones via an Intramolecular O-Arylation

What is it about?

Unreported 2-substituted 4H-pyrido[e][1,3]oxazin-4-ones are synthesized via an unprecedented intramolecular O-arylation of N-aroyl- and N-heteroaroyl-(iso)nicotinamides under microwave irradiations, in good to excellent yields. The broad applicability was demonstrated by 24 examples with a variety of substituents at the 2-position of the final compounds and 3 possible positions for the nitrogen atom of the pyridine ring. In addition, transformation of one of these compounds into 2-hydroxypyridyl-substituted 1,2,4-triazole and 1,2,4-oxazinone was realized. This approach opens a rapid access to a new bicyclic heteroaromatic chemical series with high potential in medicinal chemistry.

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Why is it important?

This new compounds are essential for the possible discovery of original scafolds for drug discovery. Pitt and coll proposed them as interesting targets for molecular chemists in 2009.