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Topic: Handling small azides  (Read 8843 times)

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Offline Johte

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Re: Handling small azides
« Reply #15 on: May 24, 2014, 09:21:19 AM »
It was suggested to me that at the micro-milli scale the acid wash wouldn't be dangerous.

I attempted in pyridine and lost the product when trying to remove pyridine in vacuo. I retried replacing the pyridine with methanol. I'm also still learning how much silica to use per g product. I was told as a general rule 25-30 g silica / 1 g product. With that ratio and just hexane, there was multiple co-elutions and still at that none of them seemed to correlate to a higher polarity species of starting material.

I used PMA wash and I2/silica jar to develop the plates. I have no doubt that most of my problems come down to my technique. I'm just trying to pinpoint where my issue is.

Offline discodermolide

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Re: Handling small azides
« Reply #16 on: May 24, 2014, 11:30:47 AM »
Really the best method is change to DCM/H2O or toluene/water, may be better as separation and work-up are easier. Good stirring and use tetra-n-butylammonium bromide as phase transfer catalyst. Sodium azide dissolved in water with catalyst keeping the pH around 9 should avoid any HN3 formation, halide in organic.
For work-up just separate organic, water wash if required and remove solvent. Or just do your next reaction in that solvent.
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Offline Johte

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Re: Handling small azides
« Reply #17 on: May 27, 2014, 11:34:26 PM »
Alrighty discodermolide,

I have ordered the TBABr. Would you have literature on this route so my only reasons for going this route arn't "some guy on the internet." :)

Offline discodermolide

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Re: Handling small azides
« Reply #18 on: May 28, 2014, 04:52:15 AM »
I have a method for benzyl azide preparation, which I know is applicable to aliphatic azides. PM me with a e-mail and I will send it to you.
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