3.8 g of 5-indanyl-2-nitropropene is dissolved in 100 mL of MeOH with stirring. Then 0.9 g of NaBH4 is added a spatula tip full at a time, over a period of 20 minutes. 20 mL of 20% HCl and a spatula tip full of Hg(NO2)2 are added to the solution. Then 5 g of 1×1 cm aluminum foil pieces are added over a period of 45 minutes with stirring. After an hour after the addition, 5 g more of the aluminum foil pieces are added and the mixture is stirred overnight. The mixture is then diluted with MeOH with stirring and filtered, the filtrate is collected. The step is repeated 3 times. Then the solvents are removed using a rotary evaporator, the residue is basified with 300 mL of 30% aq. NaOH solution. Then the freebase is extracted using 3x 40 mL of ether, the extracts are washed with 3x 40 mL of 5% HCl. The aqueous extracts are basified with sodium hydroxide until the pH reaches 14, and the freebase is extracted using 3x 30 mL of DCM. The DCM extracts are dried with anhydrous MgSO4 and the solvent is removed using a rotary evaporator. The residue is then diluted with 15 mL of cold dry ether and gassed with dry HCl gas to precipitate the pure product as the hydrochloride salt. A highly pure product is obtained by a recrystallization from boiling IPA.
Addition of the borohydride
The solution after the addition of the borohydride
The mixture after completion
The crude product as a freebase
The mixture after addition of HCl gas
The crude product as an HCl salt
The recrystallized product as an HCl salt