Potassium Hydroxide → 3-Bromo-5,7-dimethylpyrazolo(1,5-a)pyrimidine

HRID 838847Notes

Reaction equation

HRID 838847 reaction equation
[CH3:1][C:2]1[CH:7]=[C:6]([CH3:8])[N:5]2[N:9]=[CH:10][CH:11]=[C:4]2[N:3]=1.[Br:12]N1C(=O)CCC1=O.[OH-].[K+]>C(Cl)(Cl)Cl>[Br:12][C:11]1[CH:10]=[N:9][N:5]2[C:6]([CH3:8])=[CH:7][C:2]([CH3:1])=[N:3][C:4]=12

Participants

5

Reactant 3

HCID 14797Potassium HydroxideHCID 67184N-bromobutanimideHCID 215186Pyrazolo(1,5-a)pyrimidine, 5,7-dimethyl-

Product 1

HCID 1982353-Bromo-5,7-dimethylpyrazolo(1,5-a)pyrimidine

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a solution of 2.0g (13.6 mmloes) 5,7-dimethyl pyrazolo[1,5-a]-pyrimidine [Y. Makisumi, Chem. Pharm. Bull. (Tokyo) 10, 612 (1962)] in CHCl3 (25 ml) was added N-bromosuccinimide (NBS) [2.42 g (13.6 mmloes)]. This mixture was heated on the steam bath for 10 minutes, and then allowed to cool to room temperature. The clear yellow solution was then added to an ice cold solution of potassium hydroxide (50 ml, 2N) with good stirring. The CHCl3 layer was dried over Na2SO4, then chromatographed on basic alumina. Evaporation on the CHCl3 eluant afforded a white solid which was further purified by recrystallization from petroleum ether (30°-60°) to give 1.7g (56%) of analytically pure product; mp 115°-6°.

Workup

  1. temperatureThis mixture was heated on the steam bath for 10 minutes
  2. dry with materialThe CHCl3 layer was dried over Na2SO4
  3. customchromatographed on basic alumina
  4. customEvaporation on the CHCl3 eluant
  5. customafforded a white solid which
  6. customwas further purified by recrystallization from petroleum ether (30°-60°)
  7. customto give 1.7g (56%) of analytically pure product

Sources & evidence

ORD record
ord-8c5c51c255d34b859988b4c1e106b6c1
Source dataset
uspto-grants-1978_06
Patent number
US04093617

Reaction notes

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