Boron tribromide → (S)-5-amino-2'-bromo-4'-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9'-xanthen]-7'-ol
Reaction equation
[Br:1][C:2]1[CH:15]=[C:14]([F:16])[C:13]2[O:12][C:11]3[C:6](=[CH:7][C:8]([O:17]C)=[CH:9][CH:10]=3)[C@:5]3([N:23]=[C:22]([NH2:24])[CH2:21][O:20][CH2:19]3)[C:4]=2[CH:3]=1.B(Br)(Br)Br>C(Cl)Cl>[NH2:24][C:22]1[CH2:21][O:20][CH2:19][C@:5]2([C:4]3[CH:3]=[C:2]([Br:1])[CH:15]=[C:14]([F:16])[C:13]=3[O:12][C:11]3[C:6]2=[CH:7][C:8]([OH:17])=[CH:9][CH:10]=3)[N:23]=1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
In a 50-mL flask, the (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.340 g, 0.864 mmol) was taken up in DCM (15 mL). The suspension was cooled to 0° C., and a DCM solution of boron tribromide (2.59 mL, 2.59 mmol) was added. After 1 h, the reaction was quenched with 18 mL of saturated aqueous NH4Cl and 2 mL of aqueous NH4OH. The mixture was diluted further with water (10 mL), and the aqueous phase was extracted with 5% MeOH-DCM (3×50 mL). The organics were combined, washed with dilute brine (15 mL), dried over sodium sulfate and concentrated to afford 241 mg of (S)-5-amino-2′-bromo-4′-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-7′-ol which was used in the next step without further purification.
Workup
- customthe reaction was quenched with 18 mL of saturated aqueous NH4Cl and 2 mL of aqueous NH4OH
- additionThe mixture was diluted further with water (10 mL)
- extractionthe aqueous phase was extracted with 5% MeOH-DCM (3×50 mL)
- washwashed with dilute brine (15 mL)
- dry with materialdried over sodium sulfate
- concentrationconcentrated
Sources & evidence
- ORD record
- ord-35435c6d745a4035b99b4d945035564e
- Source dataset
- uspto-grants-2013_07
- Patent number
- US08497264B2
Reaction notes
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