Benzoic acid, 4-amino-3-hydroxy-, methyl ester → Methyl 2-methylbenzo[d]oxazole-6-carboxylate

Temperature

160 °C

In a 50 ml round-bottomed three-necked flask equipped with a 12-inch Vigraux column and a Dean Stark trap assembly were placed methyl 4-amino-3-hydroxybenzoate (10.0 g, 60 mmole), trimethylorthoacetate (10.8 g, 90 mmole), and concentrated sulfuric acid (0.25 g, 2.6 mmole). The resulting well-stirred mixture was heated at 115° C. until approximately 8 ml of methanol were collected in the Dean Stark trap. The reaction mixture was heated at 160° C. for another 60 minutes. The reaction mixture was cooled to room temperature and dissolved in ethyl acetate. The resulting organic solution was extracted sequentially with saturated aqueous sodium bicarbonate (1×100 ml), water (2×50 ml), brine, and dried over anhydrous magnesium sulfate. The solvent was removed in the rotary evaporator yielding 7.1 g of the expected methyl 2-methylbenzoxazole-6 carboxylate used as such in the next step.

1. customIn a 50 ml round-bottomed three-necked flask equipped with a 12-inch Vigraux column
2. customwere collected in the Dean Stark trap
3. temperatureThe reaction mixture was cooled to room temperature
4. dissolutiondissolved in ethyl acetate
5. extractionThe resulting organic solution was extracted sequentially with saturated aqueous sodium bicarbonate (1×100 ml), water (2×50 ml), brine
6. dry with materialdried over anhydrous magnesium sulfate
7. customThe solvent was removed in the rotary evaporator

ORD record

ord-8f69e8788a74488fb6ccd845b3bcc152

Source dataset

uspto-grants-1998_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05811427