Hydrochloric Acid → 5-Methoxy-3-methylpyrazine-2-carboxylic acid

Temperature

45 °C

A flask was charged with sodium (0.813 g, 35.4 mmol), purged with Argon. and placed in a room temperature water bath. Methanol (47.7 mL, 1179 mmol) was added slowly. After 40 min, methyl 5-chloro-3-methylpyrazine-2-carboxylate (step 3, 2.2 g, 11.79 mmol) was added. The vessel was sealed and heated to 45° C. for 1.5 hs. Sodium hydroxide (1M, 12.97 mL, 12.97 mmol) was added and heating was continued for 1.5 hs. The reaction mixture was concentrated uncle reduced pressure and the residue was dissolved in a minimum amount of water (50 mL). The aqueous phase was extracted with diethyl ether (15 mL), which was discarded. The aqueous phase was acidified with HCl (5M, 11 mL, 55 mmol). The mixture was extracted with DCM (3×60 mL). The combined organic extracts were dried over MgSO4 and the filtrate was concentrated to afford the title compound (2.0 g, 100%). MS m/z=169 [M+H]+. Calculated for C7H8N2O3: 168. 1H NMR in CDCl3 δ: 10.70 (br, 1H), 7.98 (s, 1H), 4.00 (s, 3H), 2.91 (s, 3H).

1. custompurged with Argon
2. customplaced in a room temperature
3. customThe vessel was sealed
4. temperatureheating
5. concentrationThe reaction mixture was concentrated uncle reduced pressure
6. dissolutionthe residue was dissolved in a minimum amount of water (50 mL)
7. extractionThe aqueous phase was extracted with diethyl ether (15 mL), which
8. extractionThe mixture was extracted with DCM (3×60 mL)
9. dry with materialThe combined organic extracts were dried over MgSO4
10. concentrationthe filtrate was concentrated

ORD record

ord-ca3324f5af184efd96b44c041c31514b

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09296734B2