24小時(shí)熱門版塊排行榜

返回列表

yyy911019

新蟲 (小有名氣)

應(yīng)助: 1 (幼兒園)
金幣: 22.5
散金: 160
紅花: 1
帖子: 188
在線: 120.6小時(shí)
蟲號(hào): 3458828
注冊: 2014-10-07
性別: MM
專業(yè): 中藥學(xué)其他科學(xué)問題

[求助] 幫忙翻譯一下這個(gè)合成實(shí)驗(yàn)步驟

Synthesis of Ginkgotoxine-5'-Glucoside
   Acetic anhydride (0.8 mL) was added dropwise to a solution of ginkgotoxin
(1.90 g), triethylamine (1.6 mL), and dimethylaminopyridine (0.38 g) in
dichloromethane (60 mL), under ice-cooling. The mixture was stirred under
ice-cooling for 20 min, and then the solvent was evaporated in vacuo. The
residue was diluted with saturated sodium hydrogen carbonate and extracted
with ethyl acetate. The organic layer was washed with saturated sodium
hydrogen carbonate and dried over anhydrous sodium sulfate. After evaporation
of the solvent, the crude product was purified by column chromatography
on silica gel, using chloroform/methanol (50/1, v/v) as an eluent,
to give 3-acetoxy-5-hydroxymethyl-4-methoxymethyl-2-methylpyridine
(ginkgotoxin-3-acetate) (1.16 g) as a pale yellow oily product. IR
(neat):3300 (OH), 1775 (C55O). 1H-NMR (CDCl3):2.34 (3H, s, CH3CO-),
2.36 (3H, s, 2-CH3), 3.33 (3H, s, 4-CH2OCH3), 4.45 (2H, s, 4-CH2OCH3),
4.64 (2H, s, 5-CH2OH), 8.31 (1H, s, 6-H).
      A mixture of ginkgotoxin-3-acetate (1.82 g), 2, 3, 4, 6-tetra-O-acetyl-a-
D-glucopyranosyl bromide (3.99 g),[12] silver carbonate (2.68 g), and
Molecular Sieves 3A (14 g) in dry dichloromethane (50 mL) was refluxed
for 3 days in the dark. After removal of insoluble materials by filtration,
the solvent was evaporated in vacuo. The crude product was purified by
column chromatography on silica gel using benzene/acetone (5/1) and recrystallization from ethyl acetate/hexane, to give ginkgotoxin-50-glucoside
pentaacetate (2.0 g) as colorless prisms. mp: 126–1278C. IR (nujol):1750
(C55O). 1H-NMR (CDCl3):1.96, 1.98, 1.99, 2.08, 2.33 (each 3H, s, CH3CO-),
2.39 (3H, s, 2-CH3), 3.26 (3H, s, 4-CH2OCH3), 3.67 (1H, ddd, J ¼ 2.3, 4.6,
10.0 Hz, Glc H-5), 4.14 (1H, dd, J ¼ 2.3, 12.0 Hz, Glc H-6), 4.24 (1H, dd,
J ¼ 4.6, 12.0 Hz, Glc H-6), 4.36, 4.40 (2H, AB, J ¼ 12.0 Hz, 4-CH2O-),
4.54 (1H, d, J ¼ 8.0 Hz, Glc H-1), 4.69, 4.97 (2H, AB, J ¼ 12.6 Hz,
5-CH2O-), 4.98-5.09 (3H, m, Glc H-2, H-3, H-4), 8.31 (1H, s, 6-OH).
   Potassium hydroxide, 2M(2 mL) was added to a solution of ginkgotoxin-
50-glucoside pentaacetate (222 mg) in methanol (4 mL). The mixture was
stirred at room temperature overnight in the dark. The pH was adjusted to
8–9 with acetic acid, and the solvent was evaporated in vacuo. The residue
was dissolved in a minimal amount of water and was applied to a reversedphase
column (240 15 mm) equilibrated with water. After washing the
column with water, elution was accomplished with 3% methanol. The
eluate was lyophilized to give ginkgotoxin- 50-glucoside as white crystals
(115 mg). mp: 128–1338C. IR (nujol):3400 (OH). 1H-NMR (D2O-DMSOd6):
2.32 (3H, s, 2-CH3), 2.92-3.11 (4H, m, Glc H-2, H-3, H-4, H-5), 3.23
(3H, s, 4-CH2OCH3), 3.42 (1H, dd, J ¼ 5.7, 11.7 Hz, Glc H-6), 3.65 (1H,
dd, J ¼ 1.7, 11.7 Hz, Glc H-6), 4.13 (1H, d, J ¼ 7.4 Hz, Glc H-1), 4.52, 4.55
(2H, AB, J ¼ 11.4 Hz, 4-CH2O-), 4.54, 4.78 (2H, AB, J ¼ 12.0 Hz, 5-CH2O-),
7.92 (1H, s, 6-H). UV lmax (5mM potassium phosphate, pH 2.5) nm:291.
ESI-MS m/z:346 [M þ H]þ.

回復(fù)此樓

» 猜你喜歡

一志愿武理085500機(jī)械專業(yè)總分300求調(diào)劑已經(jīng)有6人回復(fù)
材料學(xué)求調(diào)劑已經(jīng)有5人回復(fù)
考研調(diào)劑已經(jīng)有4人回復(fù)
281求調(diào)劑已經(jīng)有4人回復(fù)
0805 316求調(diào)劑已經(jīng)有6人回復(fù)
085601求調(diào)劑總分293英一數(shù)二已經(jīng)有3人回復(fù)
08工學(xué)調(diào)劑已經(jīng)有17人回復(fù)
340求調(diào)劑已經(jīng)有4人回復(fù)
311求調(diào)劑已經(jīng)有3人回復(fù)
食品專碩一志愿雙一流 328 已經(jīng)有4人回復(fù)

1樓 2015-03-26 15:33:31

已閱關(guān)注TA 給TA發(fā)消息送TA紅花 TA的回帖

智能機(jī)器人

Robot (super robot)

我們都愛小木蟲

找到一些相關(guān)的精華帖子，希望有用哦~

這是審稿人的comments，不太明白啥意思，哪位大神能幫忙解釋下已經(jīng)有6人回復(fù)
麻煩各位蟲友幫我翻譯下這篇文獻(xiàn)，完整翻譯20金幣，分析文獻(xiàn)10金幣已經(jīng)有8人回復(fù)
導(dǎo)師回復(fù)中，這句話不能完全理解！請幫忙翻譯已經(jīng)有7人回復(fù)
求幫忙兩段德文翻譯已經(jīng)有3人回復(fù)
實(shí)驗(yàn)操作求翻譯已經(jīng)有13人回復(fù)
請問一下這句話用英語怎么說已經(jīng)有8人回復(fù)
編輯來信，不懂，求大俠幫忙翻譯！已經(jīng)有8人回復(fù)
請解釋一下這段話。關(guān)于能帶簡并的。謝謝已經(jīng)有11人回復(fù)
論文回信有這么一句話，求各位大神幫忙翻譯一下審稿人這句話是什么意思已經(jīng)有17人回復(fù)
請哪位幫我一下，這種字體是怎么打出來的？已經(jīng)有7人回復(fù)
德語實(shí)驗(yàn)操作翻譯已經(jīng)有2人回復(fù)
有機(jī)實(shí)驗(yàn)過程，求英文翻譯，大神們趕緊來看看啊已經(jīng)有8人回復(fù)
日語合成方法翻譯已經(jīng)有1人回復(fù)
AFM樣品制備英文文獻(xiàn)翻譯已經(jīng)有7人回復(fù)
請幫忙看看回復(fù)意見怎么翻譯（一句話）已經(jīng)有8人回復(fù)
跪求英語達(dá)人翻譯一下這個(gè)計(jì)算式已經(jīng)有4人回復(fù)
化學(xué)合成步驟，翻譯過了不是太明白！急求助已經(jīng)有5人回復(fù)
【求助】請教一步反應(yīng)的英文文獻(xiàn)操作！已經(jīng)有7人回復(fù)
大家?guī)兔Ψg一下，什么意思已經(jīng)有8人回復(fù)
【求助】誰幫我翻譯一下這段德文的有機(jī)合成文獻(xiàn)啊已經(jīng)有8人回復(fù)
【求助】有機(jī)合成中的Aqueous layer應(yīng)該如何翻譯已經(jīng)有5人回復(fù)
【求助】投稿中幾個(gè)翻譯（在線等）已經(jīng)有5人回復(fù)
【求助】幫忙翻譯一下文獻(xiàn)（有機(jī)合成）已經(jīng)有7人回復(fù)

點(diǎn)擊這里搜索更多相關(guān)資源

科研從小木蟲開始，人人為我，我為人人

相關(guān)版塊跳轉(zhuǎn) 我要訂閱樓主 yyy911019 的主題更新