N-bromobutanimide → 3-Bromo-5,7-dichloropyrazolo[1,5-a]pyrimidine

HRID 1904529Notes

Reaction equation

HRID 1904529 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[N:5]2[N:9]=[CH:10][CH:11]=[C:4]2[N:3]=1.[Br:12]N1C(=O)CCC1=O>C(Cl)(Cl)Cl>[Br:12][C:11]1[CH:10]=[N:9][N:5]2[C:6]([Cl:8])=[CH:7][C:2]([Cl:1])=[N:3][C:4]=12

Participants

4

Reactant 2

HCID 67184N-bromobutanimideHCID 110741545,7-Dichloropyrazolo[1,5-a]pyrimidine

Product 1

HCID 147503553-Bromo-5,7-dichloropyrazolo[1,5-a]pyrimidineYield 99.3%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a solution of 5.3 g of 5,7-dichloropyrazolo(1,5-a)pyrimidine in 70 ml of chloroform was added portionwise 6 g of N-bromosuccinimide while keeping the temperature below 40° C. The resulting solution was refluxed for 30 minutes and was then stirred at room temperature for 12 hours. The suspension was then filtered. The filtrate was washed with 50 ml of cold 10% sodium hydroxide aqueous solution twice and was then dried over MgSO4. The chloroform solution was then concentrated under reduced pressure to give 7.47 g of the desired product, m.p. 73°-75° C.

Workup

  1. customthe temperature below 40° C
  2. temperatureThe resulting solution was refluxed for 30 minutes
  3. filtrationThe suspension was then filtered
  4. washThe filtrate was washed with 50 ml of cold 10% sodium hydroxide aqueous solution twice
  5. dry with materialwas then dried over MgSO4
  6. concentrationThe chloroform solution was then concentrated under reduced pressure

Sources & evidence

ORD record
ord-0490b71736b148aa95b88f2051841249
Source dataset
uspto-grants-1989_06
Patent number
US04838925

Reaction notes

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