Citric Acid → cis-(3aRS,9bRS)-7-(2-fluorobenzenesulfonylamino)-1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-6-carboxylic acid

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Reaction Steps

A mixture of lithium hydroxide (0.5 g) and methyl cis-(3aRS,9bRS)-7-(2-fluorobenzenesulfonyl-amino)-1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-6-carboxylate (Intermediate 58, 0.217 g) in a mixture of dioxane (13 mL) and water (4 mL) was divided between two microwave vials and the mixtures were irradiated in the microwave at 150° C. for 10 minutes. After cooling, the combined mixture was acidified by addition of 10% aqueous citric acid (2 mL), extracted with DCM, dried (MgSO4) and filtered. The filtrate was evaporated to dryness to give cis-(3aRS,9bRS)-7-(2-fluorobenzenesulfonylamino)-1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-6-carboxylic acid (0.518 g) as a glass.

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