2-Methyl-4,9-dioxo-4,9-dihydrooxazolo

Linearly annelated 2-methyl-4,9-dioxo-4,9-dihydrooxazolo[4,5-g]quinoline 14 was prepared in 31% yield by cyclization of 6-acetamido-7-chloro-5,8-dioxo-5,8-dihydroquinoline in acetic anhydride and sulfuric acid (59LA108). 

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