modified oligos

Lawrence Washington lwashing at sunflower.bio.indiana.edu
Fri Sep 16 16:01:29 EST 1994


In article <Pine.3.88.9409121811.B13542-0100000 at merck.BCH.UMontreal.CA>,
dragonf at MERCK.BCH.UMONTREAL.CA (Francois DRAGON) wrote:
> 
> What is the best and quickest way to deprotect oligonucleosid 
> methylphosphonates?
> Is it possible to use concentrated ammonia/ethanol?

	This topic is discussed extensively by Hogrefe et al in Protocols for
Oligonucleotides and Analogs vol 20.  Their "best" way is pretty involved,
including changing the dC protecting group from benzoyl to isobutyryl.
	
	A simpler method (they say gives low yields) is:

2 h room temp in concentrated ammonium hydroxide
4-6 h room temp in ethylenediamine/95% EtOH (1:1)

I have not tried this so I cannot say how well it works, but there it is.



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