[23SigmaTropic]

Hi All,

I'm trying to brominate pyrrole at the 2 position using AIBN and DBDMH and put a T-boc on the pyrrole nitrogen in situ. The Org Synth prep says to filter the 2-bromopyrrole solution, which is at -78 C, into a new flask which is also cooled to -78. To this solution you add the reagents to install the tboc.  I tried filtering with a cannula having filter paper secured on one end, but I got a bunch of what looks to the tribrominated product. I think i let it get too warm in the transfer.

Does anyone know a way to  filter a cold solution under inert conditions? I am trying to find something on it in my lab techniques book but there doesn't seem to be any well known ways of doing it.

Thanks!

[phth]

https://en.wikipedia.org/wiki/Schlenk-frit
Seems like you could be using a different reagent that is easier to handle such as trichlorocyanuric acid aka TCCA.