Potassium Carbonate → 6-Bromo-2-(trimethylsilyl)pyrazolo[1,5-a]pyrazine

HRID 341234Notes

Reaction equation

HRID 341234 reaction equation
C1(C)C=C(C)C=C(C)C=1S(O[NH2:13])(=O)=O.[Br:15][C:16]1[CH:21]=[N:20][C:19]([C:22]#[C:23][Si:24]([CH3:27])([CH3:26])[CH3:25])=[CH:18][N:17]=1.C([O-])([O-])=O.[K+].[K+].NN1C=CN=CC1>C(Cl)Cl.CN(C=O)C>[Br:15][C:16]1[N:17]=[CH:18][C:19]2[N:20]([N:13]=[C:23]([Si:24]([CH3:26])([CH3:25])[CH3:27])[CH:22]=2)[CH:21]=1

Participants

7

Reactant 4

HCID 11430Potassium CarbonateHCID 11830845O-(2,4,6-Trimethylbenzenesulfonyl)hydroxylamineHCID 54017740pyrazin-1(2H)-amineHCID 574976862-Bromo-5-trimethylsilanylethynyl-pyrazine

Product 1

HCID 574976876-Bromo-2-(trimethylsilyl)pyrazolo[1,5-a]pyrazineYield 7.6%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
0 °C

Procedure

O-(Mesitylenesulfonyl)hydroxylamine (680 mg, 3.2 mmol) was added in one portion to a stirred solution of 2-bromo-5-trimethylsilanylethynyl-pyrazine (Step 1, 3 mmol) in CH2Cl2 (3 ml) at 0° C. The mixture was stirred at 0° C. for 30 minutes, at RT for 4 hours, then evaporated. The N-amino adduct was used without further manipulation. K2CO3 (410 mg, 3 mmol) was added to a stirred solution of the N-aminopyrazine from above in dry DMF (5 ml) at RT under nitrogen. After 6 hours the mixture was partitioned between EtOAc/H2O. The organic layer was washed with brine (×2), then evaporated. The residue was taken up in CH2Cl2 and passed through a phase separating cartridge. The filtrate was evaporated and the residue was purified by chromatography on silica (2→4% EtOAc/Petrol) to give the title compound (62 mg, oil) MS: [M+H]+ 270/272.

Workup

  1. customevaporated
  2. customAfter 6 hours the mixture was partitioned between EtOAc/H2O
  3. washThe organic layer was washed with brine (×2)
  4. customevaporated
  5. customseparating cartridge
  6. customThe filtrate was evaporated
  7. customthe residue was purified by chromatography on silica (2→4% EtOAc/Petrol)

Sources & evidence

ORD record
ord-b7acd7237df44c6e99bd99b322f9b2c8
Source dataset
uspto-grants-2014_11
Patent number
US08895745B2

Reaction notes

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