Formic Acid → 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-benzo[b]pyrrolo[1,2-d][1,4]oxazine-6-carboxylic acid

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Reaction Steps

A suspension of methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-benzo[b]pyrrolo[1,2-d][1,4]oxazine-6-carboxylate (Intermediate 15, 0.074 g) and lithium hydroxide monohydrate (0.060 g) in dioxane (2 mL) and water (0.5 mL) was irradiated in the microwave at 130° C. for 45 minutes. After cooling, the mixture was acidified to pH3 with formic acid, diluted with ethanol and toluene and concentrated in vacuo. The residue was triturated with a solution of methanol in DCM (10%) 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 0-6%. The resultant solid was triturated with a mixture of ethyl acetate and ether and the solid obtained was dried in vacuo at 60° C. overnight to give 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-benzo[b]pyrrolo[1,2-d][1,4]oxazine-6-carboxylic acid (0.012 g) as a white solid.

Provenance & Evidence