Ethyl thiooxamate → Ethyl 4-isopropylthiazole-2-carboxylate

1-Bromo-3-methylbutan-2-one (3.72 g) in ethanol (15 mL) was added dropwise over 15 minutes to a refluxing solution of ethyl 2-amino-2-thioxoacetate (3 g) in ethanol (120 mL). The mixture was heated at reflux for 2 hours and then cooled to room temperature. The solvent was evaporated down under reduced pressure to a volume of 30 mL, this solution was added to ice/water (200 mL) and the mixture neutralised by dropwise addition of ‘880’ concentrated aqueous ammonia. The mixture was extracted twice with ethyl acetate, the combined organics were washed with brine, dried over sodium sulphate, filtered and the solvent evaporated under reduced pressure. The crude product was purified by flash silica chromatography eluting with 20% ethyl acetate in isohexane. Pure fractions were evaporated to dryness to afford the subtitled compound. Yield 2.2 g.

1. temperatureThe mixture was heated
2. temperatureat reflux for 2 hours
3. customThe solvent was evaporated down under reduced pressure to a volume of 30 mL
4. additionthis solution was added to ice/water (200 mL)
5. additionthe mixture neutralised by dropwise addition of ‘880’ concentrated aqueous ammonia
6. extractionThe mixture was extracted twice with ethyl acetate
7. washthe combined organics were washed with brine
8. dry with materialdried over sodium sulphate
9. filtrationfiltered
10. customthe solvent evaporated under reduced pressure
11. customThe crude product was purified by flash silica chromatography
12. washeluting with 20% ethyl acetate in isohexane
13. customPure fractions were evaporated to dryness

ORD-Eintrag

ord-58e413c2f5024fc68c8072edb22b80fa

Quelldatensatz

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08629271B2