Methyl 2-bromo-4-methylbenzoate → Methyl 2-isopropyl-4-methylbenzoate

Temperatur

-48 °C

To a stiffed mixture of dibromozinc (39.0 g, 173 mmol, 4.00 equiv) in THF (500 mL) under nitrogen at −48° C. was added dropwise isopropylmagnesium bromide (3 M in THF, 170 mmol) over a period of 30 min Pd(dppf)Cl2 (0.5 g, 0.05 equiv) and methyl 2-bromo-4-methylbenzoate (10.0 g, 43.7 mmol, 1.00 equiv) were added to the above reaction mixture. After stirring for 1 h at −48° C., the reaction mixture was quenched by the careful addition of 500 mL of NH4Cl (aq.). The resulting mixture was extracted with 3×500 mL of ethyl acetate. The combined organic layers were washed with 3×500 mL of brine and concentrated in vacuo. The residue was purified using silica gel column chromatography with petroleum ether (1:1) as eluent. This resulted in 6.50 g (77%) of methyl 2-isopropyl-4-methylbenzoate as a yellow oil.

1. additionwere added to the above reaction mixture
2. customthe reaction mixture was quenched by the careful addition of 500 mL of NH4Cl (aq.)
3. extractionThe resulting mixture was extracted with 3×500 mL of ethyl acetate
4. washThe combined organic layers were washed with 3×500 mL of brine
5. concentrationconcentrated in vacuo
6. customThe residue was purified
7. customThis resulted in 6.50 g (77%) of methyl 2-isopropyl-4-methylbenzoate as a yellow oil

ORD-Eintrag

ord-20212813c911466ab351572052110faf

Quelldatensatz

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08871790B2