Hydrochloric Acid → 9-Bromo-2-methyl-5,6,7,8-tetrahydro-1H-cyclopenta[b]naphthalene

Temperatur

0 °C

To a solution of 18.2 g (65.3 mmol) of 4-bromo-2-methyl-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]naphthalen-1-one in 100 ml of THF-methanol (2:1, vol.), 3.47 g (91.3 mmol) of NaBH4 was added, while vigorously stirring, over 1 h at 0° C. This mixture was stirred overnight at room temperature and then added to 300 ml of cold water and acidified with 1 M HCl to pH 1. The organic layer was separated, and the aqueous layer was extracted with 2×100 ml of methyl-tert-butyl ether. The combined extract was dried over K2CO3 and evaporated to dryness, and 300 ml of toluene was added to the yellowish oil obtained. This toluene solution was treated with a catalytic amount of pTolSO3H (ca. 0.5 g) for 15 h at reflux, cooled to room temperature, and evaporated to dryness. The crude product was purified using flash chromatography on Silica Gel 60 (40-63 μm, d 70 mm, l 150 mm; eluent: hexanes). Yield 14.1 g (82%) of white crystalline solid.

1. stirringThis mixture was stirred overnight at room temperature
2. customThe organic layer was separated
3. extractionthe aqueous layer was extracted with 2×100 ml of methyl-tert-butyl ether
4. extractionThe combined extract
5. dry with materialwas dried over K2CO3
6. customevaporated to dryness, and 300 ml of toluene
7. additionwas added to the yellowish oil
8. customobtained
9. temperatureat reflux
10. temperaturecooled to room temperature
11. customevaporated to dryness
12. customThe crude product was purified

ORD-Eintrag

ord-9290845bce8b4b88b7935c67455cd2e5

Quelldatensatz

uspto-grants-2008_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07446216B2