反应详情

温度

0 °C

A total of 145 g (0.63 mol) of 2-bromo-2-methylpropanoyl bromide were added dropwise to a suspension of 223 g (1.67 mol) AlCl3 in 200 ml of CH2Cl2 with vigorous stirring for 15 min at 0° C. This mixture was stirred for 45 min at this temperature; then a solution of 83.4 g (0.63 mol) of tetraline in 200 ml of CH2Cl2 was added dropwise. The mixture was slowly warmed to ambient temperature, stirred additionally overnight, and, then, poured on 1000 cm3 of ice. The organic layer was separated, the aqueous layer was extracted with 3×300 ml of CH2Cl2. The combined organic fractions were dried over MgSO4 and evaporated to dryness. Fractional distillation gave a yellowish mixture of the title indanones, b.p. 183-190° C./7 mm Hg. This mixture was recrystallized from 300 ml of n-hexane. Crystals of 2-methyl-1,2,6,7,8,9-hexahydro-3H-cyclopenta[a]naphthalen-3-one that precipitated at −30° C. were filtered off, washed with 2×25 ml of cold n-hexane, and dried in vacuum. Yield 56.5 g (45%). The filtrate was evaporated to dryness and dried in vacuum. This procedure gave 39.3 g (31%) of pure 2-methyl-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]naphthalen-1-one.

1. stirringThis mixture was stirred for 45 min at this temperature
2. temperatureThe mixture was slowly warmed to ambient temperature
3. stirringstirred additionally overnight
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with 3×300 ml of CH2Cl2
6. dry with materialThe combined organic fractions were dried over MgSO4
7. customevaporated to dryness
8. distillationFractional distillation
9. customgave
10. customThis mixture was recrystallized from 300 ml of n-hexane
11. customCrystals of 2-methyl-1,2,6,7,8,9-hexahydro-3H-cyclopenta[a]naphthalen-3-one that precipitated at −30° C.
12. filtrationwere filtered off
13. washwashed with 2×25 ml of cold n-hexane
14. customdried in vacuum
15. customThe filtrate was evaporated to dryness
16. customdried in vacuum