Lithium Hydroxide → 8-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-pyrazolo[5,1-a]isoquinoline-7-carboxylic acid

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Reaction Conditions

Reaction Steps

A mixture of methyl 8-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-pyrazolo[5,1-a]isoquinoline-7-carboxylate (Intermediate 1, 0.075 g) and lithium hydroxide (3M aqueous solution, 2 mL) in dioxane (6 mL) was heated to 80° C. for 6 hours. The resultant mixture was cooled and concentrated in vacuo. The residue was acidified using formic acid and then concentrated in vacuo. The residue was partitioned between ethyl acetate and water and the organic layer was dried (MgSO4) and filtered. The filtrate was concentrated in vacuo and the residue was triturated with methanol. The mixture was centrifuged and the supernatant was decanted twice. The resultant solid was dried in vacuo overnight to give 8-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-pyrazolo[5,1-a]isoquinoline-7-carboxylic acid (0.044 g) as a solid.

Provenance & Evidence