Ethanol → 4-(9H-pyrido[2,3-b]indol-6-yl)thiazol-2(3H)-one

A solution of potassium thiocyanate (73 mg, 0.73 mmol, 2 equiv.) in Ethanol (1 mL), was added dropwise a solution of compound 2-Bromo-1-(9H-pyrido[2,3-b]indol-6-yl)ethanone (150 mg, 0.366 mmol) in ethanol (1 mL). The mixture was stirred at reflux for 1 hour. The resulting mixture was then cautiously quenched at 0° C. with H2O. It was extracted with EtOAc. The resulting organic layer was washed with NaCl saturated aqueous solution, dried over MgSO4, and filtered. Solvent was removed under reduced pressure The crude product was triturated and filtered. The resulting product (82 mg, 0276 mmol) was dissolved in glacial acetic acid (1 mL), 50% sulfuric acid (200 μL) was added, and then the mixture was heated to reflux for 1 hour. The resulting mixture was quenched at 0° C. with H2O. The aqueous layer is treated with Na2CO3 until pH=6 and then extracted with AcOEt (3×20 ml). The organic layers was washed with NaCl saturated aqueous solution, dried over MgSO4, and filtered. Solvent was removed under reduced pressure. A white powder was obtained in 23% yield after trituration of the crude product in MeOH and filtration; 1H NMR (300 MHz, DMSO-d6): δ 11.96 (bs, 1H), 11.78 (bs, 1H), 8.48-8.43 (m, 3H), 7.74 (dd, 1H, J=1.9, 8.5 Hz), 7.52 (d, 1H, J=8.5 Hz), 7.25 (dd, 1H, J=5.5, 7.2 Hz), 6.69 (d, 1H, J=1.9 Hz), 4.75 (bs, 1H); MS (ESI) m/z 268.1 [M+H+]

1. temperatureat reflux for 1 hour
2. customThe resulting mixture was then cautiously quenched at 0° C. with H2O
3. extractionIt was extracted with EtOAc
4. washThe resulting organic layer was washed with NaCl saturated aqueous solution
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. customSolvent was removed under reduced pressure The crude product
8. customwas triturated
9. filtrationfiltered
10. dissolutionThe resulting product (82 mg, 0276 mmol) was dissolved in glacial acetic acid (1 mL)
11. addition50% sulfuric acid (200 μL) was added
12. temperaturethe mixture was heated
13. temperatureto reflux for 1 hour
14. customThe resulting mixture was quenched at 0° C. with H2O
15. additionThe aqueous layer is treated with Na2CO3 until pH=6
16. extractionextracted with AcOEt (3×20 ml)
17. washThe organic layers was washed with NaCl saturated aqueous solution
18. dry with materialdried over MgSO4
19. filtrationfiltered
20. customSolvent was removed under reduced pressure
21. customA white powder was obtained in 23% yield
22. filtrationafter trituration of the crude product in MeOH and filtration

ORD record

ord-701fd2885c0543a99a44ae31d976e655

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08895744B2