Malonic Acid → 6-Bromo-4-hydroxy-7-methoxyquinolin-2(1H)-one

Temperature

105 °C

POCl3 (5.07 ml, 54.4 mmol) was added to a mixture of 4-bromo-3-methoxyaniline (10 g, 49.5 mmol) and malonic acid (5.15 g, 49.5 mmol) with thorough mixing, and the solution was then heated to 105° C. After 5 min, the reaction began to bubble vigorously and eventually formed a hard foam, and heating was continued for 1 h. After cooling, water (200 mL) was added, and the mixture was stirred for 30 min. The solid was filtered off and washed with water. 2N NaOH (300 mL) was added to the solid, and stirring was continued overnight. The remaining solid was filtered off. EtOH (5 mL) was then added to the filtrate, and the basic layer was then acidified with concentrated HCl to pH 2. The resulting solid was then filtered off and washed with water. The solid was then transferred to a flask, and the remaining water was removed by stripping off EtOH (200 mL×2). The solid was then further dried under high vacuum for 15 h to yield 8.75 g (66%) of the title compound as an off-white solid. LRMS EST (M+H)+270.2/272.2.

1. customto bubble vigorously
2. customeventually formed a hard foam
3. temperatureheating
4. waitwas continued for 1 h
5. temperatureAfter cooling
6. filtrationThe solid was filtered off
7. washwashed with water
8. addition2N NaOH (300 mL) was added to the solid
9. stirringstirring
10. waitwas continued overnight
11. filtrationThe remaining solid was filtered off
12. additionEtOH (5 mL) was then added to the filtrate
13. filtrationThe resulting solid was then filtered off
14. washwashed with water
15. customThe solid was then transferred to a flask
16. customthe remaining water was removed
17. customThe solid was then further dried under high vacuum for 15 h

ORD record

ord-7c8a879e40c945cbb638d62326e4f61b

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08591878B2