Sodium Methoxide → 2-Methoxyoxazole-5-carboxylic acid

To a solution of ethyl 2-chlorooxazole-5-carboxylate (510 mg, 2.90 mmol) in anhdryous MeCN (10 mL) and anhydrous MeOH (10 mL) is added NaOMe (628 mg, 11.62 mmol). The crude is stirred at reflux for 2 hrs. To this crude is added additional MeOH. The crude is refluxed for another 4 hrs. The crude is concentrated and is redissolved in MeOH (10 mL). To this crude is added 1 N NaOH (10 ml). The crude is stirred at room temperature for 3 hrs. The crude is quenched with concentrated HCl, PH adjusted to 7 via PH paper indicator. The crude is concentrated and diluted in water. The aq. layer is acidified with concentrated HCl and diluted in EtOAc. The organic layer is washed with water, brine, dried over MgSO4, filtered, and concentrated to give 2-methoxyoxazole-5-carboxylic acid (290 mg). HPLC retention time=0.58 minutes (condition D); MS (m+1)=144.0.

1. temperatureat reflux for 2 hrs
2. temperatureThe crude is refluxed for another 4 hrs
3. concentrationThe crude is concentrated
4. dissolutionis redissolved in MeOH (10 mL)
5. additionTo this crude is added 1 N NaOH (10 ml)
6. stirringThe crude is stirred at room temperature for 3 hrs
7. customThe crude is quenched with concentrated HCl, PH
8. concentrationThe crude is concentrated
9. additiondiluted in water
10. additiondiluted in EtOAc
11. washThe organic layer is washed with water, brine
12. dry with materialdried over MgSO4
13. filtrationfiltered
14. concentrationconcentrated

ORD record

ord-9e2adef7b8304a7ead01d446d3c16311

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08394853B2