Boron tribromide → HCID 20504347, compound

HRID 1702195Notes

Reaction equation

HRID 1702195 reaction equation
BrC[C:3]1[CH:4]=[C:5]([C:20]([O:22][CH3:23])=[O:21])[N:6]([CH3:19])[C:7]=1[C:8](=[O:18])[C:9]1[CH:14]=[CH:13][C:12]([Cl:15])=[CH:11][C:10]=1[O:16][CH3:17].B(Br)(Br)Br>C(Cl)Cl>[Cl:15][C:12]1[CH:13]=[CH:14][C:9]2[C:8](=[O:18])[C:7]3[N:6]([CH3:19])[C:5]([C:20]([O:22][CH3:23])=[O:21])=[CH:4][C:3]=3[CH2:17][O:16][C:10]=2[CH:11]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 20504350HCID 20504350, compound

Product 1

HCID 20504347HCID 20504347, compound

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent3×

Conditions

Temperature
0 °C

Procedure

To a stirred solution of methyl 4-(bromomethyl)-5-(4-chloro-2-methoxybenzoyl)-1-methylpyrrole-2-carboxylate (0.45 g, 0.0011 m) in dry methylene chloride (20 ml) at dry-ice/acetone bath temperature was added boron tribromide (1.3 ml of a 1.0 M solution in methylene chloride) all at once. After 2 hours at these temperatures, the reaction mixture was allowed to warm to 0° C. and kept in a wet-ice bath for an additional 4 hours. Methylene chloride (30 ml) was added, followed by 50 g of ice-water. The mixture was separated, the methylene chloride layer dried and concentrated to crude methyl 4-(bromomethyl)-5-(4-chlorosalicyloyl)-1-methylpyrrole-2-carboxylate which was subsequently dissolved in dry N,N-dimethylformamide (25 ml), stirred and cooled to about -50° C. before sodium hydride (57% suspension in mineral oil, 0.07 g) was added all at once. After 10 minutes, the dry-ice bath was replaced by a wet-ice bath for 2 hours, and the reaction mixture then allowed to rise to room temperature. After 1 hour, excess ether was added, followed by ice-water. The ether layer was separated, dried over sodium sulfate, and concentrated to a white solid. Trituration with hexane yielded methyl 7-chloro-4,10-dihydro-1-methyl-10-oxo-1H[1]benzoxepino[4,3-b]pyrrole-2-carboxylate as a white solid, m.p. 169°-170° C.

Workup

  1. customfor an additional 4 hours
  2. customThe mixture was separated
  3. dry with materialthe methylene chloride layer dried
  4. concentrationconcentrated to crude methyl 4-(bromomethyl)-5-(4-chlorosalicyloyl)-1-methylpyrrole-2-carboxylate which
  5. dissolutionwas subsequently dissolved in dry N,N-dimethylformamide (25 ml)
  6. temperaturecooled to about -50° C. before sodium hydride (57% suspension in mineral oil, 0.07 g)
  7. additionwas added all at once
  8. waitAfter 10 minutes
  9. customfor 2 hours
  10. customto rise to room temperature
  11. waitAfter 1 hour
  12. additionexcess ether was added
  13. customThe ether layer was separated
  14. dry with materialdried over sodium sulfate
  15. concentrationconcentrated to a white solid

Sources & evidence

ORD record
ord-e5c178c15884430a9bd03a4a8ad46c50
Source dataset
uspto-grants-1983_04
Patent number
US04380645

Reaction notes

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