Methyl chloroformate → Methyl 1-methyl-2-oxopyrrolidine-3-carboxylate

Temperatur

-78 °C

A 250 mL round-bottomed flask was charged with 1-methylpyrrolidin-2-one (5.05 mL, 52.5 mmol), LDA (43.8 mL, 78.8 mmol, 1.8 M), and THF (125 mL). The reaction mixture stirred at −78° C. for 1 hour. Methyl chloroformate (6.06 mL, 78.8 mmol), was added, and the reaction mixture was stirred at room temperature until LC-MS showed that the starting material had been consumed (4 hours). Water (125 mL) was added, and the aqueous layer was extracted with EtOAc (3×250 mL). The combined organic layers were dried over Na2SO4 and concentrated to afford the crude product 7.35 g (89%), which was used in the next step without further purification. 1H NMR (400 MHz, CDCl3) δ 3.37 (s, 3H), 3.28-3.25 (m, 2H), 2.85 (s, 3H), 2.62-2.67 (m, 1H), 2.13-2.22 (m, 1H), 1.99-2.06 (m, 1H).

1. stirringthe reaction mixture was stirred at room temperature until LC-MS
2. customhad been consumed (4 hours)
3. additionWater (125 mL) was added
4. extractionthe aqueous layer was extracted with EtOAc (3×250 mL)
5. dry with materialThe combined organic layers were dried over Na2SO4
6. concentrationconcentrated

ORD-Eintrag

ord-97dd6ff1529e4101beb5f4137f1d7f20

Quelldatensatz

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07723330B2