Tetrahydrofuran → (+) (2aS,4R)-6-acetyl-4-(di-n-propylamino)-1,2,2a,3,4,5-hexahydrobenz[cd]indol

A solution of 2.4 g (4.6 mmol) (+)-1-trityl-6-cyano-4-(di-n-propylamino)-1,2,2a,3,4,5-hexahydrobenz[cd]indole in 100 mL of THF was treated with 25 mL of 2.0M methylmagnesium bromide in diethyl ether. The reaction mixture was refluxed for 16 hr. The reaction mixture was cooled and excess Grignard reagent was decomposed with addition of saturated NH4Cl solution. The reaction mixture was extracted with ethyl acetate. The organic solution was evaporated to an oil. The oil was dissolved in 25 mL of 5N HCl and the solution was stirred at room temperature for 30 min. The acidic solution was made alkaline with the addition of excess concentrated NH4OH solution. The basic mixture was extracted twice with ethyl acetate. The combined organic solution was washed once with saturated NaCl solution and dried over MgSO4. The ethyl acetate solution was evaporated to yield 1.4 g of an oil. Chromatography of this oil over silicia gel with ethyl acetate as eluent gave 1.2 g (87%) of product. Recrystallization from hexanes yielded 840 mg of the product (+) ketone.

1. temperatureThe reaction mixture was refluxed for 16 hr
2. temperatureThe reaction mixture was cooled
3. extractionThe reaction mixture was extracted with ethyl acetate
4. customThe organic solution was evaporated to an oil
5. dissolutionThe oil was dissolved in 25 mL of 5N HCl
6. additionwith the addition of excess concentrated NH4OH solution
7. extractionThe basic mixture was extracted twice with ethyl acetate
8. washThe combined organic solution was washed once with saturated NaCl solution
9. dry with materialdried over MgSO4
10. customThe ethyl acetate solution was evaporated

ORD record

ord-42b89d4ecc9c4ad3a03f64ca5c2ac1f8

Source dataset

uspto-grants-1993_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05244911