反応 #92671

反応方程式

5,6α-epoxicholestan-3β-yl butyrate

histamine

1-Butanol

→

5α-Hydroxy-6β-[2-(1H-imidazol-4-yl)-ethylamino]-cholestan-3β-yl butyrate

収率 60.4%

溶媒

methyl-tertbutyl-ether

反応条件

後処理

1. 1
   その他equipped with a magnetic stirrer bar
2. 2
   温度the mixture heated
3. 3
   温度to reflux for 40 h
4. 4
   洗浄washed with water (5 vol) and with brine (5 vol)
5. 5
   洗浄eluted with methyl-tertbutyl-ether (3 vol)
6. 6
   その他the solvent was removed under reduced pressure

実験手順

5,6α-epoxicholestan-3β-yl butyrate (10.4 g, 22.1 mmol, 1 eq) and histamine (4.9 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-[2-(1H-imidazol-4-yl)-ethylamino]-cholestan-3β-yl butyrate as a white solid (7.8 g, 57%). In same conditions, use of ethanol as solvent (40 vol) and Ca(OTf)2 as catalyst gave a 13% yield.

出典