Isobutylene → HCID 19095414, compound

Participants

Reaction Conditions

Reaction Steps

Isobutylene (11.0 g) was condensed under argon into a solution of 1.0 g of 5,6,10,11-tetrahydro-8-methyl-benzo[g]pyrazino[1,2-a]indol-3-ol in 50 ml of methylene chloride. The solution was cooled to -78° C. and treated with 0.4 ml of trifluoromethanesulphonic acid while stirring. The mixture was stirred at -78° C. for 8 hours and at -5° C. for 30 minutes. Subsequently, 50 ml of methanol were added and the mixture was neutralized with powdered sodium hydroxide. The reaction mixture was freed from solvent and chromatographed over 100 g of aluminium oxide (neutral, III) with methylene chloride as the eluent. The crude product, 0.3 g of yellow oil, was dissolved in a 20-fold amount of ethanol and treated with 1.1 equivalents of a saturated solution of fumaric acid in ethanol. The solution was concentrated to half and treated with 5 ml of ethyl acetate. There was obtained 0.11 g (6%) of 3-tert-butoxy-5,6,10,11-tetrahydro-8-methyl-benzo[g]pyrazino[1,2-a]indole fumarate (1:1); m.pt.: 179°-181° C. (dec.).

Provenance & Evidence