تفاعل #92671

معادلة التفاعل

5,6α-epoxicholestan-3β-yl butyrate

histamine

1-Butanol

→

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

المردود 60.4%

المذيبات

methyl-tertbutyl-ether

ظروف التفاعل

المعالجة

1. 1
   أخرىequipped with a magnetic stirrer bar
2. 2
   درجة الحرارةthe mixture heated
3. 3
   درجة الحرارةto reflux for 40 h
4. 4
   غسيلwashed with water (5 vol) and with brine (5 vol)
5. 5
   غسيلeluted with methyl-tertbutyl-ether (3 vol)
6. 6
   أخرىthe solvent was removed under reduced pressure

الإجراء التجريبي

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.

المصدر