[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8]([NH:11][C:12]1[C:21]([C:22]([O:24]C)=[O:23])=[C:20]2[C:15]([CH:16]3[CH2:26][CH:17]3[CH2:18][O:19]2)=[CH:14][CH:13]=1)(=[O:10])=[O:9].O.[OH-].[Li+]>O1CCOCC1.O>[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8]([NH:11][C:12]1[C:21]([C:22]([OH:24])=[O:23])=[C:20]2[C:15]([CH:16]3[CH2:26][CH:17]3[CH2:18][O:19]2)=[CH:14][CH:13]=1)(=[O:9])=[O:10]A mixture of methyl (1aRS,7bSR)-5-(2-Fluorobenzenesulfonylamino)-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylate (Intermediate 68, 0.6 g) and lithium hydroxide monohydrate (1.5 g) in dioxane (45 mL) and water (13.8 mL) was stirred and heated at 100° C. overnight. After cooling, the mixture was concentrated under vacuum and the residue was diluted with water and acidified to pH3 with 1M hydrochloric acid. The precipitated solid was collected by filtration to give (1aRS,7bSR)-5-(2-fluorobenzenesulfonylamino)-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylic acid (0.58 g) as a white solid.
Loading…