Carbon Dioxide → Methyl 4-methylthiazole-2-carboxylate

Temperature

-78 °C

To a solution of 4-methylthiazole (10 g) in anhydrous tetrahydrofuran (200 ml) was added n-butyl lithium in hexane (34.65 ml of 1.6M solution) dropwise at −78° C. The solution was stirred at −78° C. for 1 hour, at which point carbon dioxide gas was passed through the solution for 20 mins at −78° C. The solution was then allowed to warm to room temperature over 2 hours, the precipitate was filtered off, dissolved in methanol (200 ml) and added to methanolic hydrogen chloride (200 ml). The solution was stirred at room temperature overnight. The solvent was removed under vacuum and diethyl ether was added to the residue. The resultant solid was filtered off to yield the title compound as a white solid (2.2 g). 1H NMR (250 MHz, DMSO) δ 2.44 (3H, s), 3.89 (3H, s), 7.74 (1H, s).

1. waitwas passed through the solution for 20 mins at −78° C
2. temperatureto warm to room temperature over 2 hours
3. filtrationthe precipitate was filtered off
4. dissolutiondissolved in methanol (200 ml)
5. additionadded to methanolic hydrogen chloride (200 ml)
6. stirringThe solution was stirred at room temperature overnight
7. customThe solvent was removed under vacuum and diethyl ether
8. additionwas added to the residue
9. filtrationThe resultant solid was filtered off

ORD record

ord-02471f0b778843d6bd1ae9ea0b67acff

Source dataset

uspto-grants-2002_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06444666B1