Ethyl bromopyruvate → Ethyl 2-aminothiazole-4-carboxylate

2-Amino-thiazole-4-carboxylic acid ethyl ester was prepared by a modification to the procedure of Kumar, R.; Rai, D. et al., Heterocyclic Communications 2002, 8, 521-530. Thiourea (18.45 g, 240 mmol) was suspended in absolute ethanol (192 mL) and to this was added ethyl bromopyruvate (52 g, 240 mmol) over 5 minutes. The solution was stirred at room temperature overnight and then concentrated in vacuo and taken into water (400 mL) and 6 N aqueous hydrochloric acid (44 mL). The aqueous mixture was washed with ethyl acetate (2×) and back extracted with water (50 mL). The combined aqueous solution was adjusted to pH=10 with sodium hydroxide and extracted with 10% dichloromethane in tetrahydrofuran (3×200 mL). The combined organic extracts were dried over sodium sulfate, concentrated and dried in vacuum. The pale yellow solid was taken into dichloromethane (25 mL) and to the slurry was added hexanes (300 mL). The mixture was vigorously stirred for 15 minutes then filtered on a 9 cm funnel and dried in vacuum to give 2-amino-thiazole-4-carboxylic acid ethyl ester as an off white solid (38 g, 92%).

1. custom2-Amino-thiazole-4-carboxylic acid ethyl ester was prepared by a modification to the procedure of Kumar, R
2. concentrationconcentrated in vacuo
3. washThe aqueous mixture was washed with ethyl acetate (2×)
4. extractionback extracted with water (50 mL)
5. extractionextracted with 10% dichloromethane in tetrahydrofuran (3×200 mL)
6. dry with materialThe combined organic extracts were dried over sodium sulfate
7. concentrationconcentrated
8. customdried in vacuum
9. additionwas added hexanes (300 mL)
10. stirringThe mixture was vigorously stirred for 15 minutes
11. filtrationthen filtered on a 9 cm funnel
12. customdried in vacuum

ORD record

ord-08957fe698d84ef7a5ef78168f964377

Source dataset

uspto-grants-2008_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07371869B2