反应详情

温度

55 °C

To a stirred mixture of the product of Step A (0.4 g; 1.21 mmol) in 35% HCl (0.2 ml) an ice cold solution of NaNO2 (0.1 g, 1.3 mmol) in H2O (1 ml) was added at 0° C., followed by a solution of K-ethylxhanthate, freshly prepared by rapid stirring of a mixture of KOH (0.085 g, 1.5 mmol) and CS2 (0.173 g, 1.5 mmol) in a mixture of EtOH and H2O (1 ml: 1.5 ml) for 2.5 h at room temperature. The resulting mixture was stirred for 5 h at 55° C., than cooled to room temperature and extracted with EtOAc (50 ml). The organic layer was separated, washed with H2O, dried over MgSO4 and filtered. The filtrate was evaporated and the residue was diluted to 20 ml with EtOH and KOH (0.5 g, 3.62 mmol) was added. This was stirred for 5 h at reflux and the mixture was evaporated to dryness and the residue was treated with 1M HCl and extracted with EtOAc (20 ml). The organic layer was separated, dried over MgSO4 and filtered. The filtrate was evaporated and the residue was purified by FCC (SiO2, hexane/EtOAc) to give the title compound (0.1 g, 24%), as a yellow paste, which was used as such in next step. 1H NMR (CDCl3) 7.75 (b, 1H); 7.28 (d, 1H, J=7.95 Hz); 7.00 (dd, 1H, J=7.95, 2.0 Hz); 7.02 (s, 1H); 2.51-2.45 (m, 2H); 1.53 (b, 2H); 1.25 (b, 10H); 0.86 (t, 3H, J=6.42 Hz).

1. additionwas added at 0° C.
2. customfreshly prepared
3. temperaturethan cooled to room temperature
4. extractionextracted with EtOAc (50 ml)
5. customThe organic layer was separated
6. washwashed with H2O
7. dry with materialdried over MgSO4
8. filtrationfiltered
9. customThe filtrate was evaporated
10. additionwas added
11. stirringThis was stirred for 5 h
12. temperatureat reflux
13. customthe mixture was evaporated to dryness
14. additionthe residue was treated with 1M HCl
15. extractionextracted with EtOAc (20 ml)
16. customThe organic layer was separated
17. dry with materialdried over MgSO4
18. filtrationfiltered
19. customThe filtrate was evaporated
20. customthe residue was purified by FCC (SiO2, hexane/EtOAc)