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

HRID 470653Notes

Reaction equation

HRID 470653 reaction equation
B(Br)(Br)Br.[CH:5]1([C:11]2[N:15]=[C:14]([CH:16]=[CH:17][C:18]3[CH:23]=[CH:22][C:21]([O:24]C)=[C:20]([O:26]C)[CH:19]=3)[O:13][N:12]=2)[CH2:10][CH2:9][CH2:8][CH2:7][CH2:6]1>ClCCl>[CH:5]1([C:11]2[N:15]=[C:14]([CH:16]=[CH:17][C:18]3[CH:19]=[C:20]([OH:26])[C:21]([OH:24])=[CH:22][CH:23]=3)[O:13][N:12]=2)[CH2:10][CH2:9][CH2:8][CH2:7][CH2:6]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 673959833-Cyclohexyl-5-[2-(3,4-dimethoxy-phenyl)-vinyl]-[1,2,4]oxadiazole2×

Product 1

HCID 1364132264-[2-(3-Cyclohexyl-[1,2,4]oxadiazol-5-yl)-vinyl]-benzene-1,2-diol

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a cooled solution of 0.55 mL of 1M boron tribromide (5.8 mmol) in 2 mL dichloromethane, 0.8 g (2.5 mmol) of 3-cyclohexyl-5-[2-(3,4-dimethoxy-phenyl)-vinyl]-[1,2,4]oxadiazole (compound of Example 60) dissolved in 8 mL of dichloromethane was added over a period of 15-20 min at −45° C. to −40° C. The reaction mixture was stirred at −45° C. to −40° C. for 30-45 min and allowed to attain a temperature of 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 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 mixture to dissolve the solid and stirred for 10-15 min. The organic layer was separated and washed with 10 mL of 10% sodium chloride solution. The organic layer was distilled to obtain a crude residue, 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 −45° C. to −40° C
  2. customa temperature of 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 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 mixture
  8. dissolutionto dissolve the solid
  9. stirringstirred for 10-15 min
  10. customThe organic layer was separated
  11. washwashed with 10 mL of 10% sodium chloride solution
  12. distillationThe organic layer was distilled
  13. customto obtain a crude residue, which
  14. customwas purified by column chromatography (silica gel, chloroform-methanol)

Sources & evidence

ORD record
ord-a7f6ed24b30b4bd2a010c8042ea5edb4
Source dataset
uspto-grants-2014_01
Patent number
US08629277B2

Reaction notes

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