To a solution of 245.0 mg (0.63 mmol) (4R,9aR)-6-(2-ethoxycarbonyl-vinyl)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (Example 12, intermediate) in 10 ml diethyl ether were added 50.0 mg (1.32 mmol) lithium aluminium hydride. After 2 h the reaction mixture was poured into saturated aqueous potassium sodium tartrate solution and ethyl acetate then filtered through a short pad of dicalite speed plus. The aqueous phase was extracted four times with ethyl acetate and the combined organic layers were washed with brine, dried over magnesium sulfate, filtered and evaporated. The residue was purified by chromatography on silica gel (0.032–0.063 mm) with ethyl acetate:n-hexane as eluant to afford the compound as a colorless solid (50.5%).
