Tetrahydrofuran → HCID 22267236, compound

A solution of 6,7-dichloro-2-oxo-4-phenyl-2H-chromene-3-carboxylic acid (0.8 g) in THF (10 ml) was combined with DMF (1 drop) and oxalyl chloride (0.31 ml), and stirred at room temperature for 1 hour. After the reaction solution was concentrated under reduced pressure, the resultant residue was dissolved in THF (10 ml), and to which a solution of diazomethane prepared from N-methyl-N′-nitro-N-nitrosoguanidine (1.68 g) and potassium hydroxide (3.0 g) in ether (30 ml) was added dropwise. After the effervescence had ceased, the reaction solution was concentrated under reduced pressure. The resultant residue was dissolved in methanol (50 ml), combined with silver oxide, and heated under reflux for 30 minutes. After the insolubles were filtered off, the filtrate was concentrated under reduced pressure, and the residue was purified by a column chromatography (packing: silica gel, eluent: ethyl acetate-hexane=1:4). The resultant crude product of methyl (6,7-dichloro-2-oxo-4-phenyl-2H-chromen-3-yl)acetate was dissolved in acetic acid (5 ml) and concentrated hydrochloric acid (2.5 ml), and heated under reflux for 1 hour. The reaction solution was concentrated under reduced pressure, and the resultant residue was dissolved in a solvent mixture of THF (10 ml) and ethyl acetate (50 ml), and then washed with water followed by a saturated aqueous solution of sodium hydrogen carbonate and a saturated aqueous solution of sodium chloride. After drying over magnesium sulfate, the solvent was distilled off under reduced pressure, and the residue was purified by recrystallization from ethyl acetate to obtain the title compound (0.52 g, yield: 62%).

1. concentrationAfter the reaction solution was concentrated under reduced pressure
2. dissolutionthe resultant residue was dissolved in THF (10 ml)
3. customto which a solution of diazomethane prepared from N-methyl-N′-nitro-N-nitrosoguanidine (1.68 g) and potassium hydroxide (3.0 g) in ether (30 ml)
4. additionwas added dropwise
5. concentrationthe reaction solution was concentrated under reduced pressure
6. dissolutionThe resultant residue was dissolved in methanol (50 ml)
7. temperatureheated
8. temperatureunder reflux for 30 minutes
9. filtrationAfter the insolubles were filtered off
10. concentrationthe filtrate was concentrated under reduced pressure
11. customthe residue was purified by a column chromatography (packing: silica gel, eluent: ethyl acetate-hexane=1:4)
12. dissolutionThe resultant crude product of methyl (6,7-dichloro-2-oxo-4-phenyl-2H-chromen-3-yl)acetate was dissolved in acetic acid (5 ml)
13. temperatureconcentrated hydrochloric acid (2.5 ml), and heated
14. temperatureunder reflux for 1 hour
15. concentrationThe reaction solution was concentrated under reduced pressure
16. dissolutionthe resultant residue was dissolved in a solvent mixture of THF (10 ml) and ethyl acetate (50 ml)
17. washwashed with water
18. dry with materialAfter drying over magnesium sulfate
19. distillationthe solvent was distilled off under reduced pressure
20. customthe residue was purified by recrystallization from ethyl acetate

ORD record

ord-24b6e9efb4144c0da0e9ee58ac0c6749

Source dataset

uspto-grants-2005_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06974806B2