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

Temperature

105 °C

To a mixture of 4-bromo-3-methoxyaniline (10 g, 49.5 mmol) and malonic acid (5.15 g, 49.5 mmol) was added POCl3 (5.07 ml, 54.4 mmol) with thorough mixing, and it 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. To the solid was added 2N NaOH (300 mL) and stirring was continued overnight. The remaining solid was filtered off, and EtOH (5 mL) was then added to the filtrate and the basic layer was then acidified with conc. HCl to pH 2. The resulting solid was then filtered off, 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 ESI+ (M+H)+ 270.2.

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. additionTo the solid was added 2N NaOH (300 mL)
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-1c1fed9a08144d96afcb03a8b7cefd7d

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08927569B2