1-Butanol → 5alpha-Hydroxy-6beta-[4-(3-aminopropylamino)-butylamino]-cholestan-3beta-ol

Participants

Reaction Steps

5,6α-epoxicholestan-3β-ol (8.9 g, 22.1 mmol, 1 eq) and spermidine (6.4 g, 44.1 mmol, 2 eq) were charged in a round-bottomed flask equipped with a magnetic stirrer bar. 1-Butanol (70 ml, 5 vol) was added and the mixture heated to reflux for 40 h. The reaction mixture was cooled at r.t., diluted with methyl-tertbutyl-ether (5 vol) and washed with water (5 vol) and with brine (5 vol). The organic layer was passed through a silica pad (40 g) eluted with methyl-tertbutyl-ether (3 vol) then 10% Methanol/ethyl acetate (60 vol). Fractions of interest were pooled and the solvent was removed under reduced pressure to give 5α-Hydroxy-6β-[4-(3-aminopropylamino)-butylamino]-cholestan-3β-ol as a light yellow solid (6.1 g, 50%). In same conditions, use of ethanol as solvent (40 vol) and Ca(OTf)2 as catalyst gave a 11% yield.

Provenance & Evidence