Dimethyl Sulfate → Methyl 2-hydroxy-3-nitrobenzoate

To a solution of 2-hydroxy-3-nitrobenzoic acid (25 g, 136 mmol) in DMF (125 mL) was added K2CO3 (37.8 g, 273 mmol). Then dimethyl sulfate (48.2 g, 382 mmol) was added dropwise to the mixture at rt. The mixture was stirred at rt overnight. Then the reaction was quenched by the addition of the saturated aqueous NH4Cl (800 mL) at 0° C. The reaction mixture was extracted with EtOAc (500 mL×2). The combined organic layers were washed with water successively, dried over Na2SO4, filtered and concentrated under reduced pressure to give the title compound of Step A (26.8 g, 99.6% yield). 1H NMR (400 MHz, CDCl3) δ ppm 8.10-8.18 (m, 2H), 7.97-8.03 (br, 1H), 6.95-7.03 (m, 1H), 4.00 (s, 3H).

1. customThen the reaction was quenched by the addition of the saturated aqueous NH4Cl (800 mL) at 0° C
2. extractionThe reaction mixture was extracted with EtOAc (500 mL×2)
3. washThe combined organic layers were washed with water successively
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure

ORD-Eintrag

ord-862d2fc2c8854960a52e95b5f8799c66

Quelldatensatz

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08642759B2