反応 #162018

反応方程式

3β-cholestanol

potassium t-butoxide

propargyl bromide

→

product

3β-(Prop-2-ynyloxy)cholestanol

溶媒

toluene

hexane

EtOAc

反応条件

後処理

1. 1
   workup.STIRRINGThe mixture was stirred at r.t. for 3 days
2. 2
   洗浄washed with water (2×60 mL) and brine (60 mL)
3. 3
   抽出The aqueous phase was extracted once with EtOAc (20 mL)
4. 4
   乾燥The combined organic phases were dried (Na2SO4)
5. 5
   ろ過filtered
6. 6
   その他the filtrate was evaporated onto silica gel
7. 7
   その他purified by column chromatography (silica gel 2.5×24 cm, gradient elution with hexane 250 mL, hexane-EtOAc 125:5)

実験手順

3β-cholestanol (1.23 g, 3.16 mmol) was completely dissolved in anhydrous toluene (7 mL, 0.45 M) at r.t. Powdered potassium t-butoxide (1.06 g, 9.49 mmol, 3 eq) was added in one portion. The mixture was stirred at r.t. for 3 h. A solution of propargyl bromide (80 wt % in toluene, 0.94 g, 6.32 mmol, 2 eq) was added. The mixture was stirred at r.t. for 3 days. The mixture was diluted with hexane (30 mL) and EtOAc (10 mL), washed with water (2×60 mL) and brine (60 mL). The aqueous phase was extracted once with EtOAc (20 mL). The combined organic phases were dried (Na2SO4), filtered and the filtrate was evaporated onto silica gel and purified by column chromatography (silica gel 2.5×24 cm, gradient elution with hexane 250 mL, hexane-EtOAc 125:5) to give the product as a yellow solid. Recrystallization from EtOAc (3 mL) gave off-white crystals (736 mg, 55%). 1H NMR (CDCl3, 400 MHz) δ 4.18 (d, 2H, J=2.2), 3.45 (m, 1H), 2.38 (t, 1H, J=2.2), 1.99-0.57 (m, 31H), 0.89 (d, 3H, J=6.6), 0.86 (d, 3H, J=6.6), 0.86 (d, 3H, J=6.6), 0.79 (s, 3H), 0.64 (s, 3H).

出典