Dimethylformamide → 2H-Pyrido[4,3-d][1,3]oxazine-2,4(1H)-dione

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Reaction Steps

A 50 ml. flask was charged with 2.6 g. lead tetra-acetate suspended in 10 ml. dimethylformamide and stirred while a solution of 0.96 g. of 4-carbamylnicotinic acid in 5 ml. dimethylformamide was added dropwise during 10 minutes. The mixture was stirred for 10 minutes after completion of the addition, then poured onto 40 g. crushed ice. A precipitate of cream solids was collected by filtration, washed with water and dried in vacuo. The yield of 5-azaisatoic anhydride amounted to 0.68 g., melting point 180° with decomposition, and represented 72 percent of theory. On attempted purification by crystallization from organic solvents, extensive decomposition occurred. The structure was confirmed by elemental analysis, infra-red spectroscopy and mass spectrometry.

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