Water → 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylic acid

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Reaction Steps

A mixture of methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonyl-amino]-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylate (Intermediate 1, 0.249 g), lithium hydroxide monohydrate (0.474 g), dioxan (9 mL) and water (2.25 mL) was irradiated in the microwave at 135° C. for 45 minutes. The resulting solution was diluted with methanol, acidified with formic acid and evaporated in vacuo. The residue was dissolved in ethanol and toluene and evaporated in vacuo. The residue was triturated with 20% methanol in dichloromethane and filtered. The filtrate was evaporated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM with a gradient of 0-30% to give a gum which was dissolved in acetone. A solid precipitated out on standing. This was collected by filtration to give 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylic acid (0.178 g) as a white solid.

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