Boron tribromide → (R)-2'-bromo-7'-hydroxyspiro[morpholine-3,9'-xanthen]-5-one
Reaction equation
[Br:1][C:2]1[CH:15]=[CH:14][C:13]2[O:12][C:11]3[C:6](=[CH:7][C:8]([O:16]C)=[CH:9][CH:10]=3)[C:5]3([CH2:22][O:21][CH2:20][C:19](=[O:23])[NH:18]3)[C:4]=2[CH:3]=1.B(Br)(Br)Br>C(Cl)Cl.O>[Br:1][C:2]1[CH:15]=[CH:14][C:13]2[O:12][C:11]3[C:6](=[CH:7][C:8]([OH:16])=[CH:9][CH:10]=3)[C@:5]3([CH2:22][O:21][CH2:20][C:19](=[O:23])[NH:18]3)[C:4]=2[CH:3]=1Participants
5
Conditions
- Temperature
- -78 °C
Procedure
In a 25-mL flask, the 2′-bromo-7′-methoxyspiro[morpholine-3,9′-xanthen]-5-one (0.094 g, 0.250 mmol) was dissolved in DCM (5 mL). The solution was cooled to −78° C., and a solution of boron tribromide (1.0 M, 0.750 mL, 0.750 mmol) in DCM was added. The mixture was warmed to 0° C. and held at that temperature for 2 h. The reaction was diluted with water (20 mL) and the aqueous phase was extracted with 3% MeOH/DCM (3×25 mL). The organics were combined, washed with dilute brine (5 mL), dried over sodium sulfate, and concentrated. The residue was purified by chromatography (70:30:1 EtOAc/hexane/MeOH) to afford (R)-2′-bromo-7′-hydroxyspiro[morpholine-3,9′-xanthen]-5-one.
Workup
- temperatureThe mixture was warmed to 0° C.
- extractionthe aqueous phase was extracted with 3% MeOH/DCM (3×25 mL)
- washwashed with dilute brine (5 mL)
- dry with materialdried over sodium sulfate
- concentrationconcentrated
- customThe residue was purified by chromatography (70:30:1 EtOAc/hexane/MeOH)
Sources & evidence
- ORD record
- ord-8e20aa71c0be4e7085317c8c28719e68
- Source dataset
- uspto-grants-2013_07
- Patent number
- US08497264B2
Reaction notes
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