p-Toluenesulfonic acid → 6-Bromo-2-tert-butylpyrazolo[1,5-a]pyrimidine

HRID 2042143Notes

Reaction equation

[C:1]([C:5]1[CH:9]=[C:8]([NH2:10])[NH:7][N:6]=1)([CH3:4])([CH3:3])[CH3:2].[Br:11][CH:12]([CH:15]=O)[CH:13]=O.CC1C=CC(S(O)(=O)=O)=CC=1>C(O)CCC>[Br:11][C:12]1[CH:13]=[N:10][C:8]2[N:7]([N:6]=[C:5]([C:1]([CH3:4])([CH3:3])[CH3:2])[CH:9]=2)[CH:15]=1

Participants

Conditions

Temperature: 100 °C

Procedure

3-tert-Butyl-1H-pyrazol-5-amine (9 g, 64.7 mmol) was dissolved in BuOH (100 ml). 2-Bromomalonaldehyde (9.76 g, 64.7 mmol) and p-TsOH*H2O (615 mg, 3.23 mmol) were added at room temperature. The mixture was stirred for 16 hours at 100° C. The reaction mixture was evaporated to dryness and the residue was purified by flash chromatography on silica gel (120 gr, 0% to 40% EtOAc in heptane) and crystallization with a small volume of diisopropylether. The crystals were washed with diisopropylether and dried for 1 hour at 50° C. and <20 mbar. The desired compound was obtained as a light yellow solid (9.5 g, 58% yield), MS: m/e=256.1/254.1 (M+H+).

Workup

customThe reaction mixture was evaporated to dryness
customthe residue was purified by flash chromatography on silica gel (120 gr, 0% to 40% EtOAc in heptane) and crystallization with a small volume of diisopropylether
washThe crystals were washed with diisopropylether
customdried for 1 hour at 50° C.

Sources & evidence

ORD record: ord-84fb90ee3f2a4b868d862b1eb4341e9e
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08586581B2

Reaction notes

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