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

HRID 470649Notes

Reaction equation

HRID 470649 reaction equation
B(Br)(Br)Br.C[O:6][C:7]1[CH:8]=[C:9]([CH:15]=[CH:16][C:17]2[O:21][N:20]=[C:19]([C:22]3[CH:23]=[N:24][CH:25]=[CH:26][CH:27]=3)[N:18]=2)[CH:10]=[CH:11][C:12]=1[O:13]C>ClCCl>[N:24]1[CH:25]=[CH:26][CH:27]=[C:22]([C:19]2[N:18]=[C:17]([CH:16]=[CH:15][C:9]3[CH:8]=[C:7]([OH:6])[C:12]([OH:13])=[CH:11][CH:10]=3)[O:21][N:20]=2)[CH:23]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 2961547HCID 2961547, compound2×

Product 1

HCID 1364132244-[2-(3-Pyridin-3-yl-[1,2,4]oxadiazol-5-yl)-vinyl]-benzene-1,2-diol

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a cooled solution of 0.35 mL of 1M boron tribromide (3.7 mmol) in 2 mL dichloromethane, 0.500 g (1.6 mmol) of 3-{5-[2-(3,4-dimethoxy-phenyl)-vinyl]-[1,2,4]oxadiazol-3-yl}-pyridine (compound of Example 54) dissolved in 5 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 in 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 the aqueous layer was washed with 10 mL of 10% sodium chloride solution. The organic layer was collected and 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 in 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. 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 residue, which
  15. customwas purified by column chromatography (silica gel, chloroform-methanol)

Sources & evidence

ORD record
ord-263e8dd32d1e406baeb2d34829a51dd0
Source dataset
uspto-grants-2014_01
Patent number
US08629277B2

Reaction notes

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