Hydrochloric Acid → Methyl 2-ethyl-5-oxo-6-(piperidin-4-yl)-5,6,7,8-tetrahydro-1,6-naphthyridine-3-carboxylate dihydrochloride

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Reaction Steps

A mixture of 2M hydrogen chloride (methanol solution, 236 mL) and methyl 6-(1-(tert-butoxycarbonyl)piperidin-4-yl)-2-ethyl-5-oxo-5,6,7,8-tetrahydro-1,6-naphthyridine-3-carboxylate (19.7 g) was stirred at room temperature under nitrogen atmosphere for 4 hours and concentrated in vacuo. The residue was crystallized from methanol and ethyl acetate. After filtration, the crystals were washed with ethyl acetate to give the title compound (18.5 g).

Provenance & Evidence