Formic Acid → 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-2,3-dihydro-1H-pyrrolo[1,2-a]indole-8-carboxylic acid

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Reaction Steps

A suspension of methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-2,3-dihydro-1H-pyrrolo[1,2-a]indole-8-carboxylate (Intermediate 16, 0.092 g) and lithium hydroxide monohydrate (0.077 g) in dioxane (2 mL) and water (0.5 mL) was irradiated in the microwave at 135° C. for 45 minutes. After cooling, the mixture was acidified to pH4 with formic acid. Ethanol and toluene were added and the resultant mixture was concentrated in vacuo. The residue was triturated with methanol in DCM (10% solution) and the solid was filtered off and washed with DCM. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM with a gradient of 0-8%. The resultant solid was triturated with ethyl acetate and dried in vacuo, at 60° C. overnight to give 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-2,3-dihydro-1H-pyrrolo[1,2-a]indole-8-carboxylic acid (0.039 g) as a pale yellow solid.

Provenance & Evidence