Sodium hydride → 6-Bromo-1-methyl-2,2-dioxo-pyrido[3,2-c]thiazin-4-one

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Reaction Steps

To a three necked flask flushed with argon was added NaH (60%, 0.75 g, 18.7 mmol) followed by DMF (10 ml) and stirring was continued for 5 min followed by addition of a solution of ethyl 6-bromo-3-[methyl(methylsulfonyl)amino]pyridine-2-carboxylate (3.16 g, 9.37 mmol) in DMF (35 ml, rinsed with 2×2.5 ml) at ambient temperature giving a reddish solution under effervescence. After stirring for 1 hour the reaction mixture was concentrated under reduced pressure followed by addition of water and ethyl acetate then the phases were separated. The acqueous phase was made slightly acidic using H2SO4 (95-97%) followed by extraction with methylene chloride. The combined organic phases were dried over Na2SO4, filtered and concentrated in vacuo. Purification by flash chromatography eluting with ethyl acetate/heptane, gradient, afforded 6-bromo-1-methyl-2,2-dioxo-pyrido[3,2-c]thiazin-4-one as a yellow solid.

Provenance & Evidence