July 11, 2020, 04:32:06 AM
Forum Rules: Read This Before Posting


Topic: Handling small azides  (Read 7203 times)

0 Members and 1 Guest are viewing this topic.

Offline Johte

  • Regular Member
  • ***
  • Posts: 23
  • Mole Snacks: +0/-0
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

  • Chemist
  • Sr. Member
  • *
  • Posts: 5038
  • Mole Snacks: +404/-70
  • Gender: Male
    • My research history
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.
Development Chemists do it on Scale, Research Chemists just do it!
My Research History

Offline Johte

  • Regular Member
  • ***
  • Posts: 23
  • Mole Snacks: +0/-0
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

  • Chemist
  • Sr. Member
  • *
  • Posts: 5038
  • Mole Snacks: +404/-70
  • Gender: Male
    • My research history
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.
Development Chemists do it on Scale, Research Chemists just do it!
My Research History

Sponsored Links