Boron tribromide → HCID 53677600, compound

HRID 52273Notes

Reaction equation

HRID 52273 reaction equation
Cl.[CH:2]1([N:6]([C@@H:10]2[CH2:15][C:14]3[C:16]([O:21]C)=[CH:17][CH:18]=[C:19]([F:20])[C:13]=3[O:12][CH2:11]2)[CH2:7][CH2:8][CH3:9])[CH2:5][CH2:4][CH2:3]1.B(Br)(Br)Br>C(Cl)Cl>[CH:2]1([N:6]([C@@H:10]2[CH2:15][C:14]3[C:16]([OH:21])=[CH:17][CH:18]=[C:19]([F:20])[C:13]=3[O:12][CH2:11]2)[CH2:7][CH2:8][CH3:9])[CH2:3][CH2:4][CH2:5]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 22871217HCID 22871217, compound

Product 1

HCID 53677600HCID 53677600, compoundYield 98.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
-40 °C

Procedure

(R)-3-(N-Cyclobutyl-N-n-propylamino)-8-fluoro-5-methoxy-3,4-dihydro-2H-1 -benzopyran hydrochloride (1.0 g, 3.03 mmol) was dissolved in anhydrous CH2Cl2 (25 mL) and cooled to -40° C. To the solution was BBr3 (0.72 mL, 7.6 mmol), dissolved in anhydrous CH2Cl2 (4 mL), added dropwise. The cooling-bath was removed and after 2 h at room temperature the reaction was complete. The reaction was poured out onto an ice/2M NH3 solution and the CH2Cl2 portion was separated, the aqueous layer re-extracted, twice, with CH2Cl2. The combined CH2Cl2 portions were dried (MgSO4), filtered, and the solvent removed in vacuo to give the crude residue. Chromatography on silica (eluent: 25% ethyl acetate/hexane followed by 50% ethyl acetate/hexane) gave 0.83 g (98% yield) of the title compound as a gum. [α]21D =-80.5° (C=0.1; CHCl3) GC-MS (70 eV) M=279 (0.2%).

Workup

  1. additionadded dropwise
  2. customThe cooling-bath was removed and after 2 h at room temperature the reaction
  3. additionThe reaction was poured out onto an ice/2M NH3 solution
  4. customthe CH2Cl2 portion was separated
  5. extractionthe aqueous layer re-extracted
  6. dry with materialThe combined CH2Cl2 portions were dried (MgSO4)
  7. filtrationfiltered
  8. customthe solvent removed in vacuo
  9. customto give the crude residue

Sources & evidence

ORD record
ord-bb310e1912194665a1b77f83e0cac2fc
Source dataset
uspto-grants-1997_04
Patent number
US05616610

Reaction notes

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