Anthranilic Acid → 2H-1,2-Benzoxazin-3(4H)-one

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Reaction Steps

Coupling of a pyrazolecarboxylic acid of Formula 6 wherein R4 is H with an anthranilic acid of Formula 7 provides the benzoxazinone of Formula 8. In Scheme 7, a benzoxazinone of Formula 8 is prepared directly via sequential addition of methanesulfonyl chloride in the presence of a tertiary amine such as triethylamine or pyridine to a pyrazolecarboxylic acid of Formula 6 wherein R4 is H, followed by the addition of an anthranilic acid of Formula 7, followed by a second addition of tertiary amine and methanesulfonyl chloride.

Provenance & Evidence