Formic Acid → (1aRS,7bSR)-5-{2-[((S)-1-ethylpyrrolidin-3-ylcarbamoyl)methyl]-4-fluorobenzenesulfonyl-amino}-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylic acid

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Reaction Steps

A mixture of methyl (1aRS,7bSR)-5-{2-[((S)-1-ethylpyrrolidin-3-ylcarbamoyl)methyl]-4-fluorobenzenesulfonylamino}-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylate (Intermediate 80, 0.148 g) and lithium hydroxide monohydrate (0.168 g) in dioxane (3 mL) and water (1 mL) was irradiated in the microwave at 130° C. for 40 minutes. After cooling, the mixture was diluted with methanol, acidified with formic acid and evaporated in vacuo. The residue was triturated with 10% methanol in DCM 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 0-20%. The resultant solid was triturated with ether and filtered off to give (1aRS,7bSR)-5-{2-[((S)-1-ethylpyrrolidin-3-ylcarbamoyl)methyl]-4-fluorobenzenesulfonyl-amino}-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylic acid (0.091 g) as a white solid.

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