[OH-].[Li+].[N:3]1([CH2:8][CH2:9][CH2:10][C:11]2[CH:16]=[C:15]([F:17])[CH:14]=[CH:13][C:12]=2[S:18]([NH:21][C:22]2[C:31]([C:32]([O:34]C)=[O:33])=[C:30]3[C:25]([C@H:26]4[CH2:38][CH2:37][O:36][C@H:27]4[CH2:28][O:29]3)=[CH:24][CH:23]=2)(=[O:20])=[O:19])[CH2:7][CH2:6][CH2:5][CH2:4]1.C(O)=O>O1CCOCC1.O>[N:3]1([CH2:8][CH2:9][CH2:10][C:11]2[CH:16]=[C:15]([F:17])[CH:14]=[CH:13][C:12]=2[S:18]([NH:21][C:22]2[C:31]([C:32]([OH:34])=[O:33])=[C:30]3[C:25]([C@H:26]4[CH2:38][CH2:37][O:36][C@H:27]4[CH2:28][O:29]3)=[CH:24][CH:23]=2)(=[O:20])=[O:19])[CH2:7][CH2:6][CH2:5][CH2:4]1Lithium hydroxide (0.028 g) was added to a solution of methyl cis-(3aRS,9bRS)-7-[2-(3-{pyrrolidin-1-yl}propyl)-4-fluorobenzenesulfonylamino]-1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-6-carboxylate (Intermediate 14, 0.06 g) in dioxane (2 mL) and water (1 mL) and the mixture was stirred and heated at 80° C. for 8 hours. After cooling, the mixture was acidified by addition of aqueous formic acid solution (10%) and extracted with DCM. The organic layer was dried (MgSO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica eluting with a mixture of ammonia in methanol (2M) and DCM with a gradient of 1-10%. The isolated solid was triturated with a mixture of ether and cyclohexane (50%) and the solid was collected by filtration. The solid was purified by preparative HPLC (C18) eluting with a mixture of acetonitrile and water, containing 0.1% formic acid, with a gradient of 10-95%. The isolated product was triturated with ether and the solid was collected by filtration to give cis-(3aRS,9bRS)-7-[2-(3-{pyrrolidin-1-yl}propyl)-4-fluorobenzenesulfonylamino]-1,3a,4,9b-tetrahydro-2H-furo[2,3-c]chromene-6-carboxylic acid (0.006 g) as a white solid.
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