反応 #3996

反応方程式

NaHCO3

2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene-1-ol

trimethyl orthoformate

methanol

trifluoroacetic acid

→

1-methoxy-2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene

溶媒

THF

THF

反応条件

後処理

1. 1
   抽出extracted with chloroform three times
2. 2
   抽出The combined organic extract
3. 3
   洗浄is washed with water
4. 4
   乾燥dried over Na2SO4
5. 5
   その他evaporated in vacuo
6. 6
   その他to give a residue, which
7. 7
   その他is purified by HPLC (4% ether in hexane, silica gel column)

実験手順

To a solution of 2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene-1-ol (1.6 g, 5 mmol), 106 g (10 mmol) of trimethyl orthoformate and 160 mg (5 mmol) of dry methanol in 5 ml of dry THF is added dropwise a solution of 40 μL of trifluoroacetic acid in 1 ml of dry THF over a 1 minute period at room temperature. After overnight standing, the reaction mixture is poured into cold aqueous 5% NaHCO3 and extracted with chloroform three times. The combined organic extract is washed with water, dried over Na2SO4 and evaporated in vacuo to give a residue, which is purified by HPLC (4% ether in hexane, silica gel column) to afford of 1-methoxy-2,5,9-trimethyl-11-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8,10-undecapentaene as an oil.

出典