5-Bromoisatin → HCID 68990201, compound

Temperature

40 °C

To a 500 mL round-bottomed flask, was added 5-bromoisatin (5.00 g, 22.1 mmol), formaldehyde dimethyl acetal (111 mL, 22.1 mmol), and boron trifluoride diethyl etherate (16.7 mL, 133 mmol). The resulting mixture was heated at 40° C. TLC (1:1 hexane:EtOAc) showed starting material was consumed. The mixture was then diluted with EtOAc (100 mL) and washed with brine/water (60 mL), brine (60 mL) and brine/bicarbonate (60 mL). The organic layer was dried over sodium sulfate and evaporated to provide an orange solid. The solid was taken up in EtOAc (50 mL) with heating, and hexane (10 mL) was added until the mixture became cloudy. A black precipitate formed immediately that should have been removed. The mixture was heated to reflux and allowed to stand at room temperature and then at −20° C. Orange red crystals were filtered washing with hexane and manually separated from the black precipitate to provide the title compound (2.97 g, 49.7% yield) as a red crystalline solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 3.29 (s, 3H), 5.08 (s, 2H), 7.19 (d, J=8.22 Hz, 1H), 7.77 (s, 1H), 7.85 (s, 1H).

1. customwas consumed
2. additionThe mixture was then diluted with EtOAc (100 mL)
3. washwashed with brine/water (60 mL), brine (60 mL) and brine/bicarbonate (60 mL)
4. dry with materialThe organic layer was dried over sodium sulfate
5. customevaporated
6. customto provide an orange solid
7. temperaturewith heating
8. customA black precipitate formed immediately
9. customthat should have been removed
10. temperatureThe mixture was heated
11. temperatureto reflux
12. customto stand at room temperature
13. customat −20° C
14. filtrationOrange red crystals were filtered
15. washwashing with hexane
16. custommanually separated from the black precipitate

ORD record

ord-64587bfdd6f44aa5a55b0e2281340b4f

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07514566B2