Perchloric Acid → 5-Bromo-3-(2-methoxyphenyl)-1H-pyrrolo[2,3-b]pyridine

HRID 901436Notes

Reaction equation

HRID 901436 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([C:9]([C:13]2[CH:18]=[CH:17][C:16](OC)=[CH:15][CH:14]=2)=[CH:10]OC)[C:5]([NH2:8])=[N:6][CH:7]=1.Cl(O)(=O)(=O)=O.[O:26]1CCOC[CH2:27]1>>[Br:1][C:2]1[CH:3]=[C:4]2[C:9]([C:13]3[CH:14]=[CH:15][CH:16]=[CH:17][C:18]=3[O:26][CH3:27])=[CH:10][NH:8][C:5]2=[N:6][CH:7]=1

Participants

4

Reactant 3

HCID 24247Perchloric AcidHCID 312751,4-DioxaneHCID 67061221HCID 67061221, compound

Product 1

HCID 596997875-Bromo-3-(2-methoxyphenyl)-1H-pyrrolo[2,3-b]pyridineYield 82%

Conditions

Temperature
100 °C

Procedure

A 50 ml round bottomed flask was charged with 403 mg of 5-bromo-3-[2-methoxy-1-(4-methoxy-phenyl)-vinyl]-pyridin-2-ylamine (1.2 mmol; combined E- and Z-isomers), 1,4-dioxane (5 ml), and 70% aqueous perchloric acid (250 μl). The flask was fitted with a reflux condenser and nitrogen inlet adapter and heated in an oil bath to 100° C. for 8 hours. The reaction mixture was concentrated, then treated with 15 ml of a saturated aqueous solution of sodium bicarbonate followed by ethyl acetate (20 ml). The layers were separated, and the aqueous fraction was extracted twice with ethyl acetate. The combined organic fractions were washed with brine, dried (Na2SO4), filtered, and concentrated. The residue was triturated with ether to afford 300 mg (82%) of 5-bromo-3-(2-methoxy-phenyl)-1H-pyrrolo[2,3-b]pyridine as a tan powder. 1H-NMR (d6-DMSO) δ=12.16 (br. s, 1H), 8.36 (d, 1H), 8.18 (d, 1H), 7.82 (d, 1H), 7.58 (d, 1H), 7.36 (t, 1H), 7.19 (d, 1H), 7.10 (t, 1H), 3.88 (s, 3H); MS m/z: 303 [MH]+.

Workup

  1. customThe flask was fitted with a reflux condenser and nitrogen inlet adapter
  2. concentrationThe reaction mixture was concentrated
  3. additiontreated with 15 ml of a saturated aqueous solution of sodium bicarbonate
  4. customThe layers were separated
  5. extractionthe aqueous fraction was extracted twice with ethyl acetate
  6. washThe combined organic fractions were washed with brine
  7. dry with materialdried (Na2SO4)
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customThe residue was triturated with ether

Sources & evidence

ORD record
ord-444142435a8740a58435aefdad5cf302
Source dataset
uspto-grants-2008_04
Patent number
US07361763B2

Reaction notes

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