Phosphorus oxybromide → HCID 178444245, compound

HRID 904605Notes

Reaction equation

HRID 904605 reaction equation
[CH2:1]([C@H:6]1[CH2:11][CH2:10][C@H:9]([C:12]2[CH:13]=[CH:14][C:15](=O)[NH:16][N:17]=2)[CH2:8][CH2:7]1)[CH2:2][CH2:3][CH2:4][CH3:5].P(Br)(Br)([Br:21])=O>C1(C)C=CC=CC=1>[Br:21][C:15]1[N:16]=[N:17][C:12]([C@H:9]2[CH2:10][CH2:11][C@H:6]([CH2:1][CH2:2][CH2:3][CH2:4][CH3:5])[CH2:7][CH2:8]2)=[CH:13][CH:14]=1

Participants

4

Reactant 2

HCID 24613Phosphorus oxybromide3×HCID 178444364HCID 178444364, compound

Product 1

HCID 178444245HCID 178444245, compoundYield 173.8%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
68 °C

Procedure

24.8 g of 6-(trans-4-pentylcyclohexyl)-3(2H)-pyridazinone (prepared according to Example 2) and 150 ml of toluene were suspended in a sulphonation flask under nitrogen. Subsequently, there was added dropwise within 7 minutes a solution of 11.5 g of phosphorus oxybromide, the temperature rising from 17° C. to 30° C. and a viscous light brown mass resulting. The mixture was treated with 30 ml of toluene and then heated slowly to 68° C., whereby it became dark green in colour. After 2 hours, a solution of 5.7 g of phosphorus oxybromide was added dropwise at 68° C. within 10 minutes. The mixture was heated to reflux temperature and once more treated with a solution of 7.4 g of phosphorus oxybromide. After 6 hours, the mixture was poured into 400 ml of ice/water and extracted six times with 250 ml of methylene chloride each time. The organic phases were washed with 400 ml of 5% sodium hydrogen carbonate solution, subsequently combined, dried with sodium sulphate and concentrated at 40° C. on a rotary evaporator. Column chromatography on silica gel with ethyl acetate/hexane (1:1) as the eluant gave 24.81 g of crude product. Crystallization from 75 ml of ethyl acetate/hexane (2:1) and working-up of the mother liquor finally yielded a total of 21.7 g of 3-bromo-6-(trans-4-pentylcyclohexyl)pyridazine as white crystals of melting point 101°-103° C.

Workup

  1. customrising from 17° C. to 30° C.
  2. customa viscous light brown mass resulting
  3. temperatureThe mixture was heated
  4. temperatureto reflux temperature
  5. waitAfter 6 hours
  6. extractionextracted six times with 250 ml of methylene chloride each time
  7. washThe organic phases were washed with 400 ml of 5% sodium hydrogen carbonate solution
  8. dry with materialdried with sodium sulphate
  9. concentrationconcentrated at 40° C. on a rotary evaporator
  10. customColumn chromatography on silica gel with ethyl acetate/hexane (1:1) as the eluant gave 24.81 g of crude product
  11. customCrystallization from 75 ml of ethyl acetate/hexane (2:1)

Sources & evidence

ORD record
ord-858a25a9eb0a40b8b44e38e72a892973
Source dataset
uspto-grants-1983_12
Patent number
US04419262

Reaction notes

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