Lithium Hydroxide → (1aRS,7bSR)-5-(4-fluoro-2-vinylbenzenesulfonylamino)-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylic acid

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Reaction Steps

Lithium hydroxide (0.101 g) was added to a solution of methyl (1aRS,7bSR)-5-(4-fluoro-2-vinylbenzenesulfonylamino)-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylate (Intermediate 75, 0.150 g) in a mixture of dioxane (3 mL) and water (0.6 mL) and the mixture was irradiated in the microwave at 130° C. for 30 minutes. After cooling, the mixture evaporated to dryness and the residue was acidified by addition of 10% aqueous citric acid (2 mL), extracted with DCM, dried (MgSO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica eluting with a mixture of methanol and DCM with a gradient of 0-10% to give (1aRS,7bSR)-5-(4-fluoro-2-vinylbenzenesulfonylamino)-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylic acid (0.0.35 g) as a glass.

Provenance & Evidence