Water → Dimethyl 4,7-dimethylpyrazolo[1,5-a]pyrazine-2,3-dicarboxylate
Reaction equation
[NH2:1][N+:2]1[CH:7]=[C:6]([CH3:8])[N:5]=[CH:4][C:3]=1[CH3:9].CC1C=C(C)C=C(C)C=1S([O-])(=O)=O.C(=O)([O-])[O-].[K+].[K+].[C:29]([O:37][CH3:38])(=[O:36])[C:30]#[C:31][C:32]([O:34][CH3:35])=[O:33].O>CN(C)C=O>[CH3:8][C:6]1[C:7]2[N:2]([N:1]=[C:30]([C:29]([O:37][CH3:38])=[O:36])[C:31]=2[C:32]([O:34][CH3:35])=[O:33])[C:3]([CH3:9])=[CH:4][N:5]=1Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 1-amino-2,5-dimethylpyrazin-1-ium-2,4,6-trimethylbenzenesulfonate (4.72 g, 14.6 mmol) in N,N-dimethylformamide (DMF) (50 mL) was added potassium carbonate (4.44 g, 32.1 mmol). The mixture was stirred at room temperature for 10 min. Then a solution of dimethyl but-2-ynedioate (1.87 g, 13.2 mmol) in DMF (30 mL) was added. The resulting mixture was stirred at room temperature for 1 h. Then the mixture was poured into water (400 mL), extracted with EtOAc (3×200 mL). The combined organic layer was dried over sodium sulfate, filtered, evaporated, and chromatographed on silica gel using 20% ethyl acetate (EtOAc) in petroleum ether (PE) as eluent to give 1.04 g (27% yield) of the title compound as a yellow solid. ESI MS: m/z 124.1 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 7.82 (d, J=0.8 Hz, 1H), 4.03 (s, 3H), 4.00 (s, 3H), 2.81 (s, 3H), 2.75 (s, 3H).
Workup
- stirringThe resulting mixture was stirred at room temperature for 1 h
- extractionextracted with EtOAc (3×200 mL)
- dry with materialThe combined organic layer was dried over sodium sulfate
- filtrationfiltered
- customevaporated
- customchromatographed on silica gel using 20% ethyl acetate (EtOAc) in petroleum ether (PE) as eluent
Sources & evidence
- ORD record
- ord-9b0bfbb3445947a6bc6105013c0f06db
- Source dataset
- uspto-grants-2014_07
- Patent number
- US08765760B2
Reaction notes
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