Diphosgene → 2H-3,1-Benzoxazine-2,4(1H)-dione, 6-nitro-

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Reaction Steps

To the mixture of 37 g of 2-amino-5-nitrobenzoic acid in 500 mL of dioxane, under stirring 24.5 mL of diphosgene was added dropwise. The mixture was heated under reflux conditions for 6 hours then it was evaporated to dryness. The residue was suspended in 100 mL of diethyl ether and filtered off to give 41.4 g of the title product as HCl salt, m.p.: 256-259° C. LC-MS: MH+ 209; Ret. time: 5 minutes.

Provenance & Evidence