Trifluoroacetic acid → Methyl (1R,3R)-1-(1,3-benzodioxol-5-yl)-2,3,4,9-tetrahydro-1H-pyrido(3,4-b)indole-3-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of D-tryptophan methyl ester (11 g) and piperonal (7.9 g) in anhydrous CH2Cl2 (400 mL) cooled at 0° C. was added dropwise trifluoroacetic acid (7.7 mL) and the solution was allowed to react at ambient temperature. After 4 days, the yellow solution was diluted with CH2Cl2 (200 mL) and washed with a saturated aqueous solution of NaHCO3, then with water (3×200 mL) and dried over Na2SO4. The organic layer was evaporated under reduced pressure and the residue containing the two geometric isomers was purified by flash chromatography eluting with dichloromethane/ethyl acetate (97/3) to give as the first eluting product the title compound (6.5 g).

Herkunft & Nachweise