Heterocyclic quinones. XVI. The Reaction of acid Amides with 2,3- Dichloro-1,4-naphthoquinone,a novel route to naphth[2,3-d]oxazole-4,9-diones

Heating acid amides 2 with 2,3-dichloro-1,4-naphthoquinone 1 in solvents like glycerol or ethylene glycol gave readily naphth 2,3-d] oxazole-4,9-diones 4 . The reaction was enhanced by addition of catalytic amounts of sodium hydrogencarbonate, but failed to proceed at all when attempted in low boiling polar or nonpolar solvents. 2-Amido-3-chloro-1,4-naphthoquinones 3 were produced as intermediates in these reactions.