Sulfuric Acid → (S)-1-{(E,3S,3aS,7aR)-7-(bromomethylene)-octahydro-3a-methyl-1H-indene-3-yl}ethanol

Temperature

0 °C

Under a nitrogen atmosphere, a suspension of bromomethyltriphenylphosphonium bromide (319 mg, 0.7304 mmol) in toluene (0.4 ml) was cooled in an ice bath, and potassium hexamethyldisilazide (0.5 M in toluene, 1.3 ml, 0.6492 mmol) was added dropwise thereto. The reaction mixture was stirred at 0° C. for 1 hour and 20 minutes, and at room temperature for 8 minutes, and then heated to 42° C. A solution of (S)-1-{(3S,3aR,7aR)-octahydro-3a-methyl-7-oxo-1H-indene-3-yl}ethyl formate (Compound 17: 36.4 mg, 0.1623 mmol) in toluene (0.25 ml) was added thereto. The vessel of (S)-1-{(3S,3aR,7aR)-octahydro-3a-methyl-7-oxo-1H-indene-3-yl}ethyl formate (Compound 17) was washed with toluene (0.1 ml×2) and the washings were added. The reaction mixture was stirred at from 41° C. to 46° C., and then cooled in an ice bath. Saturated aqueous ammonium chloride solution (2 ml), water (5 ml) and methanol (1.5 ml) were added thereto, and the resulting mixture was extracted with hexane (25 ml). The organic layer was washed with saturated brine (5 ml), dried over sodium sulfate, and evaporated under reduced pressure. The obtained crude product (169.4 mg) was dissolved in dioxane (0.5 ml), and the resulting mixture was cooled in an ice bath. To the mixture, 50 v/v % sulfuric acid (0.5 ml) was added, and the reaction mixture was stirred at room temperature (22° C.) for 1.5 hours. After cooling the resulting mixture in an ice bath, the mixture was diluted with ether (10 ml). Potassium carbonate (0.56 g) and water (5 ml) were added thereto. After separating the organic layer, the aqueous layer was extracted twice with ether (10 ml). The combined organic layer was washed with saturated brine (5 ml), dried over sodium sulfate, and evaporated under reduced pressure. The obtained crude product was purified by flash column chromatography to obtain (S)-1-{(E,3S,3aS,7aR)-7-(bromomethylene)-octahydro-3a-methyl-1H-indene-3-yl}ethanol (20.6 mg, 46.5%).

1. temperaturewas cooled in an ice bath
2. waitat room temperature for 8 minutes
3. temperatureheated to 42° C
4. washThe vessel of (S)-1-{(3S,3aR,7aR)-octahydro-3a-methyl-7-oxo-1H-indene-3-yl}ethyl formate (Compound 17) was washed with toluene (0.1 ml×2)
5. additionthe washings were added
6. stirringThe reaction mixture was stirred at from 41° C. to 46° C.
7. temperaturecooled in an ice bath
8. additionSaturated aqueous ammonium chloride solution (2 ml), water (5 ml) and methanol (1.5 ml) were added
9. extractionthe resulting mixture was extracted with hexane (25 ml)
10. washThe organic layer was washed with saturated brine (5 ml)
11. dry with materialdried over sodium sulfate
12. customevaporated under reduced pressure
13. customThe obtained crude product (169.4 mg)
14. temperaturethe resulting mixture was cooled in an ice bath
15. stirringthe reaction mixture was stirred at room temperature (22° C.) for 1.5 hours
16. temperatureAfter cooling the resulting mixture in an ice bath
17. customAfter separating the organic layer
18. extractionthe aqueous layer was extracted twice with ether (10 ml)
19. washThe combined organic layer was washed with saturated brine (5 ml)
20. dry with materialdried over sodium sulfate
21. customevaporated under reduced pressure
22. customThe obtained crude product
23. customwas purified by flash column chromatography

ORD record

ord-c9cdd2de98df4e2d92eb6fe74686cf6b

Source dataset

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08173824B2