Hydrogen Bromide → 6,6-Difluorospermine

Participants

Reaction Steps

The compound 1,12-diamino-6,6-difluoro-4,9-di-p-toluenesulfonyl-4,9-diaza-dodecane (2.7 g, 4.36 mM) and 47% aqueous HBr are refluxed (bath temperature: 110° C.) for 17 hours. After cooling to room temperature, the solution is carefully extracted with ether (three times) and finally with chloroform. Evaporation of the aqueous phase, followed by stripping with isopropanol (twice) and ethanol (twice) produces a solid residue which is digested with acetone, collected, and washed with acetone (three times), ethanol (three times) and finally with ether: white crystals, 1.8 g (74%). This material is recrystallized by dissolving in hot (80° C.) aqueous ethanol (100 mL, H2O: ethanol 1:9), filtering through paper, and adding additional ethanol (10-20 mL) to yield the desired 6,6-difluoro-1,12-diamino-4,9-diaza-dodecane as the tetrahydrobromide salt: white crystals 1.2 g, (49%).

Provenance & Evidence