N-bromobutanimide → 3-methyl-5H-dibenzo[a,d]cyclohepten-5-one

HRID 982349Notes

Reaction equation

HRID 982349 reaction equation
[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[CH2:11][CH2:10][C:9]3[CH:12]=[CH:13][CH:14]=[CH:15][C:8]=3[C:7](=[O:16])[C:6]=2[CH:17]=1.BrN1C(=O)CCC1=O>C(Cl)(Cl)(Cl)Cl>[CH3:1][C:2]1[CH:3]=[CH:4][C:5]2[CH:11]=[CH:10][C:9]3[CH:12]=[CH:13][CH:14]=[CH:15][C:8]=3[C:7](=[O:16])[C:6]=2[CH:17]=1

Participants

4

Reactant 2

HCID 67184N-bromobutanimideHCID 1314562510,11-Dihydro-3-methyl-5H-dibenzo[a,d]cyclohepten-5-one

Product 1

HCID 200675883-methyl-5H-dibenzo[a,d]cyclohepten-5-oneYield 74.1%

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

The ketone from Step B (30.25 g) and N-bromosuccinimide (29.1 g) were refluxed in carbon tetrachloride (300 ml) for 5 hrs. The solution was cooled, filtered and evaporated and the residue dissolved in dimethylformamide (100 ml) and 1,5-diazabicyclo[4.3.0]non-5-ene (22 g) added. The solution was heated to 80° for 20 mins, then poured into water (300 ml) and extracted with ether (3×300 ml). The extract was washed with dilute aqueous hydrochloric acid and water, then dried and evaporated. Crystallisation from acetone/hexane gave pure 3-methyl-5H-dibenzo[a,d]cyclohepten-5-one (22.2 g). m.p. 81°-83° C.

Workup

  1. temperatureThe solution was cooled
  2. filtrationfiltered
  3. customevaporated
  4. dissolutionthe residue dissolved in dimethylformamide (100 ml)
  5. addition1,5-diazabicyclo[4.3.0]non-5-ene (22 g) added
  6. temperatureThe solution was heated to 80° for 20 mins
  7. additionpoured into water (300 ml)
  8. extractionextracted with ether (3×300 ml)
  9. washThe extract was washed with dilute aqueous hydrochloric acid and water
  10. customdried
  11. customevaporated
  12. customCrystallisation from acetone/hexane

Sources & evidence

ORD record
ord-19330edd692e495e8919d891eea946d3
Source dataset
uspto-grants-1991_02
Patent number
US04996211

Reaction notes

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