Ethanol → 6-Bromopyrazolo[1,5-a]pyrimidine

HRID 1926758Notes

Reaction equation

HRID 1926758 reaction equation
[NH:1]1[C:5]([NH2:6])=[CH:4][CH:3]=[N:2]1.[Br:7][CH:8]([CH:11]=O)[CH:9]=O.C(O)C>>[Br:7][C:8]1[CH:9]=[C:4]2[CH:3]=[N:2][NH:1][C:5]2=[N:6][CH:11]=1.[Br:7][C:8]1[CH:9]=[N:6][C:5]2[N:1]([N:2]=[CH:3][CH:4]=2)[CH:11]=1

Participants

5

Reactant 3

HCID 702EthanolHCID 74561Pyrazol-3-ylamineHCID 749452-Bromopropanedial

Product 2

HCID 222367016-Bromopyrazolo[1,5-a]pyrimidineHCID 404274545-Bromopyrazolo[3,4-b]pyridine

Procedure

A solution of 1H-pyrazol-5-amine x79 (25 g, 1 eq, 0.3 mol) and bromomalonaldehyde x9 (45.4 g, 1 eq, 0.3 mol) ethanol (250 ml) is refluxed for 2 hours. After cooling, the reaction mixture is stirred at room temperature overnight. The solvent is removed under reduced pressure and the crude is purified using chiral chromatography affording 5-bromo-1H-pyrazolo[3,4-b]pyridine x80 (yield: 2.1%; LC-MS (MH+): 198/200) and 6-bromopyrazolo[1,5-a]pyrimidine x81 (yield: 13.8%; LC-MS (MH+): 198/200).

Workup

  1. temperatureAfter cooling
  2. customThe solvent is removed under reduced pressure
  3. customthe crude is purified

Sources & evidence

ORD record
ord-9a2357108a674ea39ebdc92de42d2da2
Source dataset
uspto-grants-2012_05
Patent number
US08183241B2

Reaction notes

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