Triethylamine → (S)-3-[3-(benzo[b]thien-2-yl)-1-oxopropyl]-4-(phenylmethyl)-2-oxazolidinone

Temperature

0 °C

To a solution of benzo[b]thiophene-2-propanoic acid (1.10 g, 5.33 mmol) and Et3N (0.89 mL, 6.4 mmol) in dry THF (22 mL) at -78° C. was added dropwise pivaloyl chloride (0.66 mL, 5.4 mmol). After the resultant white suspension was stirred for 10 min at -78° C. and 30 min at 0° C., it was recooled to -78° C. and a precooled (-78° C.) solution of metallated oxazolidinone, prepared by addition of n-BuLi (1.6M in hexane, 3.66 mL, 5.85 mmol) to a -78° C. solution of (S)-(-)-4-benzyl-2-oxazolidinone (1.05 g, 5.87 mmol) in THF (22 mL), was added via a cannula. The reaction mixture was stirred for an additional 1 h and then was quenched by addition of saturated aq. NH4Cl (36 mL). The mixture was concentrated and the residue was extracted with CH2Cl2 (3×100 mL). The combined organic phases were washed with saturated aq. NaHCO3 (85 mL), dried (Na2SO4) and concentrated to dryness. The crude solid (2.31 g) was purified by flash chromatography, eluting with EtOAc-hexane (1:2.5) to give (S)-3-[3-(benzo[b]thien-2-yl)-1-oxopropyl]-4-(phenylmethyl)-2-oxazolidinone (1.82 g, 4.98 mmol) in 93% yield as a solid, mp 119°-122° C. [α]25D +54.9° (c 0.55, CHCl3).

1. customwas recooled to -78° C.
2. additionwas added via a cannula
3. stirringThe reaction mixture was stirred for an additional 1 h
4. customwas quenched by addition of saturated aq. NH4Cl (36 mL)
5. concentrationThe mixture was concentrated
6. extractionthe residue was extracted with CH2Cl2 (3×100 mL)
7. washThe combined organic phases were washed with saturated aq. NaHCO3 (85 mL)
8. dry with materialdried (Na2SO4)
9. concentrationconcentrated to dryness
10. customThe crude solid (2.31 g) was purified by flash chromatography
11. washeluting with EtOAc-hexane (1:2.5)

ORD record

ord-78010a6bfa82435aa1844bfd015dff54

Source dataset

uspto-grants-1992_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05128448