Sodium Carbonate → 5-Oxazol-5-yl-pyrazine-2-carboxylic acid

HRID 1409716Notes

Reaction equation

HRID 1409716 reaction equation
C([O-])([O-])=O.[Na+].[Na+].C[O:8][C:9]([C:11]1[CH:16]=[N:15][C:14](Cl)=[CH:13][N:12]=1)=[O:10].CC1(C)C(C)(C)OB([C:26]2[O:30][C:29]([Si](C(C)C)(C(C)C)C(C)C)=[N:28][CH:27]=2)O1>CN(C)C=O>[O:30]1[C:26]([C:14]2[N:15]=[CH:16][C:11]([C:9]([OH:8])=[O:10])=[N:12][CH:13]=2)=[CH:27][N:28]=[CH:29]1

Participants

5

Reactant 3

HCID 10340Sodium CarbonateHCID 406081Methyl 5-chloropyrazine-2-carboxylateHCID 442243115-(Tetramethyl-1,3,2-dioxaborolan-2-yl)-2-(tris(propan-2-yl)silyl)-1,3-oxazole

Product 1

HCID 866861585-Oxazol-5-yl-pyrazine-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
80 °C

Procedure

Aqueous Na2CO3 solution (2 M, 14.5 mL) and [1,1′-bis(diphenylphosphino)-ferrocene]dichloropalladium dichloromethane complex (950 mg) are added to a mixture of 5-chloropyrazine-2-carboxylic acid methyl ester (2.00 g) and 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-[tris(isopropyl)silyl]-oxazole (4.70 g) in N,N-dimethylformamide (20 mL) under an argon atmosphere. The reaction mixture is stirred over night at 80° C. After cooling to room temperature, the solvents are evaporated, the residue is mixed water and acidified with 4 N hydrochloric acid (12 mL). A precipitate is formed upon addition of ethyl acetate, which is filtered off, washed with ethyl acetate and methanol, and dried. LC (method 7): tR=0.46 min; Mass spectrum (ESI−): m/z=190 [M−H]−.

Workup

  1. temperatureAfter cooling to room temperature
  2. customthe solvents are evaporated
  3. additionthe residue is mixed water
  4. customA precipitate is formed upon addition of ethyl acetate, which
  5. filtrationis filtered off
  6. washwashed with ethyl acetate and methanol
  7. customdried

Sources & evidence

ORD record
ord-682feb6dbb594f23b85004f8d104f678
Source dataset
uspto-grants-2014_12
Patent number
US08921398B2

Reaction notes

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