Boron tribromide → 4-[2-(3-Cyclopropyl-[1,2,4]oxadiazol-5-yl)-vinyl]-benzene-1,2-diol

HRID 470632Notes

Reaction equation

HRID 470632 reaction equation
B(Br)(Br)Br.[CH:5]1([C:8]2[N:12]=[C:11]([CH:13]=[CH:14][C:15]3[CH:20]=[CH:19][C:18]([O:21]C)=[C:17]([O:23]C)[CH:16]=3)[O:10][N:9]=2)[CH2:7][CH2:6]1>ClCCl>[CH:5]1([C:8]2[N:12]=[C:11]([CH:13]=[CH:14][C:15]3[CH:16]=[C:17]([OH:23])[C:18]([OH:21])=[CH:19][CH:20]=3)[O:10][N:9]=2)[CH2:7][CH2:6]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 673954903-Cyclopropyl-5-[2-(3,4-dimethoxy-phenyl)-vinyl]-[1,2,4]oxadiazole2×

Product 1

HCID 1364132194-[2-(3-Cyclopropyl-[1,2,4]oxadiazol-5-yl)-vinyl]-benzene-1,2-diol

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a cooled solution of 0.79 mL of 1M boron tribromide (0.79 mmol) in 2 mL dichloromethane, 0.1 g (0.34 mmol) of cyclopropyl-5-[2-(3,4-dimethoxy-phenyl)-vinyl]-[1,2,4]oxadiazole (compound of Example 36) dissolved in 1 mL of dichloromethane was added, over a period of 15-20 min at −40° C. to −45° C. The reaction mixture was stirred at −40° C. to −45° C. for 30-45 min and allowed to attain 25° C. to 30° C. slowly, over a period of 1 h. The reaction mixture was further stirred at 25° C. to 30° C. for 4-5 h. After the completion of the reaction, the reaction mixture was quenched with 10 mL of chilled 5% sodium bicarbonate solution, below 20° C. (pH: 8-9). 10 mL of ethyl acetate was added to the reaction mass to dissolve the solid and stirred for 10-15 min. The organic layer was separated and the aqueous layer was washed with 10 mL of 10% sodium chloride solution. The organic layer was collected and distilled to obtain a crude material, which was purified by column chromatography (silica gel, chloroform-methanol) to yield the title compound.

Workup

  1. additionwas added, over a period of 15-20 min at −40° C. to −45° C
  2. customto attain 25° C. to 30° C.
  3. waitover a period of 1 h
  4. stirringThe reaction mixture was further stirred at 25° C. to 30° C. for 4-5 h
  5. customAfter the completion of the reaction
  6. customthe reaction mixture was quenched with 10 mL of chilled 5% sodium bicarbonate solution, below 20° C. (pH: 8-9)
  7. addition10 mL of ethyl acetate was added to the reaction mass
  8. dissolutionto dissolve the solid
  9. stirringstirred for 10-15 min
  10. customThe organic layer was separated
  11. washthe aqueous layer was washed with 10 mL of 10% sodium chloride solution
  12. customThe organic layer was collected
  13. distillationdistilled
  14. customto obtain a crude material, which
  15. customwas purified by column chromatography (silica gel, chloroform-methanol)

Sources & evidence

ORD record
ord-c2679f15b35846f7b2194fc5689a6967
Source dataset
uspto-grants-2014_01
Patent number
US08629277B2

Reaction notes

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