d**a 发帖数: 3715 | 1 我用 5-hexyl-2,2-bithiphene 在THF中, -78 degree 与 Bu3Li/Bu3SnCl反应合成5-
tributylstannyl-5-hexyl-2,2-bithiophene。 反应进行了两次。第一次我在常温下加
入BuSnCl,反应完毕后,溶液呈金黄色。往反应液中加入50mL hexane萃取,发现溶液颜
色逐渐变为黑褐色。(就象很浓的血的颜色)。不知道是什么原因。
今天我重复了一次试验。在-78 度的时候加入 Bu3SnCl, 其它都一样。反应完毕后,
溶液呈金黄色,带一点棕色。加入Hexane后,溶液变为蓝色。(有点像铜溶液的颜色)
。跟前一次反应得到产物的颜色很不一样。
不知道班上有没有thiophene合成经验的同学赐教一二。谢谢。 |
c****c 发帖数: 36 | |
t*******e 发帖数: 440 | 3 友情顶,虽然我这辈子还没碰过Thiophene,呵呵。 |
R******d 发帖数: 5739 | 4
did u check the completion of deprotonation? although it is difficult to
check, even if by D2O, unless u r fast enough to take sample at low temp.
at -78 degree ur deprotonation is very likely incomplete, u have to warm it
up to at least -50 deg for 30 mins before adding the stannate
【在 d**a 的大作中提到】 : 我用 5-hexyl-2,2-bithiphene 在THF中, -78 degree 与 Bu3Li/Bu3SnCl反应合成5- : tributylstannyl-5-hexyl-2,2-bithiophene。 反应进行了两次。第一次我在常温下加 : 入BuSnCl,反应完毕后,溶液呈金黄色。往反应液中加入50mL hexane萃取,发现溶液颜 : 色逐渐变为黑褐色。(就象很浓的血的颜色)。不知道是什么原因。 : 今天我重复了一次试验。在-78 度的时候加入 Bu3SnCl, 其它都一样。反应完毕后, : 溶液呈金黄色,带一点棕色。加入Hexane后,溶液变为蓝色。(有点像铜溶液的颜色) : 。跟前一次反应得到产物的颜色很不一样。 : 不知道班上有没有thiophene合成经验的同学赐教一二。谢谢。
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y***q 发帖数: 55 | 5 我觉得,丁基锂在室温下加就行了,否则活性不够啊! 然后室温下加氯化锡,我们用的
联噻吩纯度很低,都是带铜盐的,原料就是绿的。 |
b*********s 发帖数: 26 | 6 溶液呈金黄色 is a good sign.
You dont need to use BuLi, LDA is strong enough.
Add LDA to the thiophene solution at around -30C. Usually the deprotonation
would take 5 mins, but you can keep it stirred for about 20 mins then add
your tin.
【在 d**a 的大作中提到】 : 我用 5-hexyl-2,2-bithiphene 在THF中, -78 degree 与 Bu3Li/Bu3SnCl反应合成5- : tributylstannyl-5-hexyl-2,2-bithiophene。 反应进行了两次。第一次我在常温下加 : 入BuSnCl,反应完毕后,溶液呈金黄色。往反应液中加入50mL hexane萃取,发现溶液颜 : 色逐渐变为黑褐色。(就象很浓的血的颜色)。不知道是什么原因。 : 今天我重复了一次试验。在-78 度的时候加入 Bu3SnCl, 其它都一样。反应完毕后, : 溶液呈金黄色,带一点棕色。加入Hexane后,溶液变为蓝色。(有点像铜溶液的颜色) : 。跟前一次反应得到产物的颜色很不一样。 : 不知道班上有没有thiophene合成经验的同学赐教一二。谢谢。
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d**a 发帖数: 3715 | 7 Thank you for all of the replies. I ran this reaction by following the
literature. Some people used diethyl ether and claimed their product is
yellow (but didn't mentioned if they used hexane for purification or not). I
think my reaction was fine before hexane was added for extraction because
in both case, the resulting solutions are yellow. But I am not very sure
what is going on after hexane was added, which caused such a big change in
the solution color. |
b*********s 发帖数: 26 | 8 didn't you quench the reaction before exraction?
I
【在 d**a 的大作中提到】 : Thank you for all of the replies. I ran this reaction by following the : literature. Some people used diethyl ether and claimed their product is : yellow (but didn't mentioned if they used hexane for purification or not). I : think my reaction was fine before hexane was added for extraction because : in both case, the resulting solutions are yellow. But I am not very sure : what is going on after hexane was added, which caused such a big change in : the solution color.
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