Ethyl chloroformate → Ethyl 3-bromo-5-fluoropyridine-4-carboxylate

To a −78° C. solution of LDA (2 M solution in heptane/THF, 14.2 mL, 28.4 mmol) in anhydrous THF (45 mL) was added a solution of the 3-bromo-5-fluoropyridine (5.0 g, 28.4 mmol) in anhydrous THF (20 mL). The reaction mixture was stirred at −78° C. for 45 minutes. Then, a solution of ethyl chloroformate (24 mL, 284 mmol) was added slowly over 10 minutes. After stirring for 20 minutes, the reaction mixture was quenched with a saturated solution of NaHCO3. The mixture was extracted into ethyl acetate (3×100 mL). The combined organic extracts were extracted with water (2×200 mL), dried over MgSO4, filtered, evaporated, and dried in vacuo, affording ethyl 3-bromo-5-fluoropyridine-4-carboxylate (4.8 g, 69% yield). The product was used without further purification.

1. stirringAfter stirring for 20 minutes
2. customthe reaction mixture was quenched with a saturated solution of NaHCO3
3. extractionThe mixture was extracted into ethyl acetate (3×100 mL)
4. extractionThe combined organic extracts were extracted with water (2×200 mL)
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. customevaporated
8. customdried in vacuo

ORD-Eintrag

ord-d642620e56f04d61b3b55d5d58a2a963

Quelldatensatz

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09315521B2