Sodium hydride → 3-Amino-1-cyclopropyl-6-fluoro-2,4-dioxo-1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidine-7-thiosulfonic acid

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Reaction Steps

A solution of 0.47 g (1.57 mmol) of 1-cyclopropyl-6-fluoro-2,4-dioxo-1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidine-7-thiosulfonic acid (Example 35) in 20 mL of dimethylformamide/dioxane (1:1) is treated portionwise with 0.08 g (2.0 mmol) of 60% sodium hydride/mineral oil. The reaction is stirred at room temperature for 1 hour and 0.32 g (1.6 mmol) of 2,4-dinitrophenylhydroxylamine is added all at once. After stirring at room temperature overnight, the dioxane is removed in vacuo and the residue is diluted to 100 mL with ice and water and stirred at 5° C. for 1 hour. The aqueous solution is extracted with ethyl acetate (3×50 mL) with the combined organic layers being washed with water, dried (MgSO4), filtered and evaporated in vacuo to give 0.4 g of the title compound, mp 167-169° C.

Provenance & Evidence