Dimethylformamide → HCID 22348184, compound

Temperature

70 °C

6,7-Dichloro-4-oxo-4H-chromene-2-carboxylic acid (19.1 mmol) and thionyl chloride (20 mL) were carefully combined. DMF (0.2 mL) was added, and the dark, hetereogeneous solution was warmed to 70° C. After 16 h, the black homogeneous solution was cooled to ambient temperature and concentrated to a dark residue. The residue was diluted with CH2Cl2 (75 mL), washed with saturated aqueous NaHCO3 (2×75 mL), washed with brine (1×50 mL), dried (MgSO4), filtered, and concentrated to an orange residue that was passed through a plug of silica gel (1:1 hexane:EtOAc). The filtrate was concentrated to a beige solid (3.2 g) that was recrystallized from CH3CN to provide the desired solid (2.6 g, 55%) as off-white crystals. MS (APCI) m/z 273 [M+Na]+; 1H NMR (300 MHz, DMSO-D6) δ ppm 7.06 (s, 1H) 7.99 (s, 1H) 8.06 (s, 1H).

1. temperaturethe black homogeneous solution was cooled to ambient temperature
2. concentrationconcentrated to a dark residue
3. additionThe residue was diluted with CH2Cl2 (75 mL)
4. washwashed with saturated aqueous NaHCO3 (2×75 mL)
5. washwashed with brine (1×50 mL)
6. dry with materialdried (MgSO4)
7. filtrationfiltered
8. concentrationconcentrated to an orange residue that
9. concentrationThe filtrate was concentrated to a beige solid (3.2 g) that
10. customwas recrystallized from CH3CN

ORD record

ord-d3e2ffcd934c4305a95dab18007b2a8a

Source dataset

uspto-grants-2005_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06921821B2