Methanol → Methyl 4,7-dimethylpyrazolo[1,5-a]pyrazine-2-carboxylate

HRID 1615610Notes

Reaction equation

[CH3:1][C:2]1[C:3]2[N:4]([N:9]=[C:10]([C:16]([O:18][CH3:19])=[O:17])[C:11]=2C(OC)=O)[C:5]([CH3:8])=[CH:6][N:7]=1.CO>S(=O)(=O)(O)O.O>[CH3:1][C:2]1[C:3]2[N:4]([N:9]=[C:10]([C:16]([O:18][CH3:19])=[O:17])[CH:11]=2)[C:5]([CH3:8])=[CH:6][N:7]=1

Participants

Conditions

Temperature: 180 °C

Procedure

A solution of dimethyl 4,7-dimethylpyrazolo[1,5-a]pyrazine-2,3-dicarboxylate (900 mg, 3.42 mmol) in sulfuric acid (4 mL) and water (1 mL) was stirred and heated to 180° C. After stirring for 2 h at that temperature, the reaction mixture was cooled, and 40 mL of methanol (MeOH) was added. The mixture was refluxed at 70° C. for 2 h. Then the mixture was concentrated to dryness. The residue was treated with water and adjusted with saturated sodium bicarbonate solution to pH 8, then extracted with EtOAc (3×100 mL). The combined organic layer was washed with brine, dried over sodium sulfate, filtered, and evaporated to give 560 mg (80% yield) of the title compound as a yellow solid. ESI MS: m/z 206.1 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 7.73 (d, J=0.8 Hz, 1H), 7.36 (s, 1H), 4.03 (s, 3H), 2.77 (s, 3H), 2.75 (s, 3H).

Workup

temperaturethe reaction mixture was cooled
temperatureThe mixture was refluxed at 70° C. for 2 h
concentrationThen the mixture was concentrated to dryness
additionThe residue was treated with water
extractionextracted with EtOAc (3×100 mL)
washThe combined organic layer was washed with brine
dry with materialdried over sodium sulfate
filtrationfiltered
customevaporated

Sources & evidence

ORD record: ord-ab6b31366edf45699eb40fe0b7b386eb
Source dataset: uspto-grants-2014_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08765760B2

Reaction notes

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