Hydrochloric Acid → 5-(1,1-Dioxido-1,2-thiazinan-2-yl)-8-hydroxy-1,6-naphthyridine-7-carboxylic acid

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Reaction Conditions

Reaction Steps

A suspension of methyl 5-(1,1-dioxido-1,2-thiazinan-2-yl)-8-hydroxy-1,6-naphthyridine-7-carboxylate (1.00 g, 2.96 mmol, prepared as described in Example 2 above) in methanol (18 mL) with aqueous lithium hydroxide (17.8 mL, 17.8 mmol, 1N solution) was stirred overnight at 60° C. The suspension was acidified to a pH=4 using 3N HCl (about 6 mL) and the resulting solution was allowed to stir overnight at room temperature. In the morning, the solids that had precipitated out of solution were collected by vacuum filtration to give the desired product as a light yellow solid.

Provenance & Evidence