Ethyl Acetate → Methyl 4-bromo-3-methyl-5-nitrobenzoate

4-Bromo-3-methylbenzoic acid methyl ester (10.13 g, 44 mmol) was dissolved in a mixture of H2SO4 120 mL and TFA (15 mL) at room temperature. The solution was cooled on an ice bath and KNO3 (4.65 g, 46 mmol) was added portionwise over 30 min. The mixture was stirred at ambient temperature for 4 hours during which it warmed to rt. TLC analysis (after mini aqueous workup) showed total disappearance of starting material (30% EtOAc/Hex). The solution was poured onto ice and the aqueous slurry was extracted with EtOAc (3×150 mL). The organic layer was washed with 5% Na2CO3 (3×75 mL), NaHCO3 (3×50 mL), water (2×100 mL), brine (100 mL), then was dried over sodium sulfate. Concentration of the solution yielded a yellowish solid/gel substance (11.6 g) which was one spot by TLC. 1H NMR analysis shows two (major) products in ˜2:1 ratio, corresponding to the o- and m-nitrobenzoate derivatives. The material was carried onto the next step without further purification.

1. temperatureThe solution was cooled on an ice bath
2. temperaturewarmed to rt
3. additionThe solution was poured onto ice
4. extractionthe aqueous slurry was extracted with EtOAc (3×150 mL)
5. washThe organic layer was washed with 5% Na2CO3 (3×75 mL), NaHCO3 (3×50 mL), water (2×100 mL), brine (100 mL)
6. dry with materialwas dried over sodium sulfate
7. customConcentration of the solution yielded a yellowish solid/gel substance (11.6 g) which
8. customThe material was carried onto the next step without further purification

ORD record

ord-1d1d1dc807174c0c93f2361c1029c2cd

Source dataset

uspto-grants-2006_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07138530B2