(+/-)-(5-Chloro-7-methoxy-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate → (+/-)-(5-Chloro-7-hydroxy-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate
Reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([O:11][CH2:12][CH:13]2[CH2:17][C:16]3[CH:18]=[C:19]([Cl:24])[CH:20]=[C:21]([O:22]C)[C:15]=3[O:14]2)(=[O:10])=[O:9])=[CH:4][CH:3]=1>Br>[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([O:11][CH2:12][CH:13]2[CH2:17][C:16]3[CH:18]=[C:19]([Cl:24])[CH:20]=[C:21]([OH:22])[C:15]=3[O:14]2)(=[O:9])=[O:10])=[CH:4][CH:3]=1Participants
Procedure
Treatment of (±)-(5-chloro-7-methoxy-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate (22.1 g, 0.06 mol) with hydrogen bromide (400 mL, 30 wt. % in acetic acid) generally according to the procedure described for Intermediate 46 gave 14.6 g of (±)-(5-chloro-7-hydroxy-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate as a colorless oil. Treatment of (±)-(5-chloro-7-hydroxy-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate (4.5 g, 12.68 mmol) with trifluoromethanesulfonic anhydride (2.34 mL, 13.9 mmol) and diisopropylethylamine (2.43 mL, 13.9 mmol) generally according to the procedure described for Intermediate 7 provided 6.27 g (99%) of (±)-(5-chloro-7-{[(trifluoromethyl)sulfonyl]oxy}-2,3-dihydro-1-benzofuran-2-yl)methyl 4-methylbenzenesulfonate as a light yellow solid. mp 55-57° C.; Anal. calcd. for C17H14ClF3O7S2: C, 41.94; H, 2.90. Found: C, 42.10; H, 2.76.
Sources & evidence
- ORD record
- ord-95faa557ed9e4aa2817e6633f6b2398e
- Source dataset
- uspto-grants-2008_10
- Patent number
- US07435837B2
Reaction notes
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