[ANDLOS]

HI to all members,

I try to make amide bond with
ester and amine or amino acid
but the yield of ester is toooooooooooo little
so i search for one sterp conversion
instead of making desterification then acid chloride then amide bond formation,
can any one help me for that item.
thanks alot

[democanarchis]

Found this paper using magnesium nitride to convert an ester directly to a primary amide, could be what you're looking for :http://dx.doi.org/10.1021/ol801398z

[sjb]

Found this paper using magnesium nitride to convert an ester directly to a primary amide, could be what you're looking for :http://dx.doi.org/10.1021/ol801398z

I think that only works for primary amides, so may not be that more useful for e.g. peptides. I have converted HetArCO₂Me to HetArCONHR with the amide salts formed from Me₃Al and amine fairly successfully in the past, tolerated things like 2-chloropyrimidines, but not so sure on the former amine side. May have the reference somewhere, if you'd like that.

[dunno260]

I have done this in the past several times using diethylaluminum chloride (a "safer" alternative to diethylaluminum chloride) in an equal ratio to the amine.  Its a variation of literature methods used to make Weinreb amides. 

[discodermolide]

HI to all members,

I try to make amide bond with
ester and amine or amino acid
but the yield of ester is toooooooooooo little
so i search for one sterp conversion
instead of making desterification then acid chloride then amide bond formation,
can any one help me for that item.
thanks alot

You don't say what kind of amide. But the best way is to heat the ester in a sealed tube with the amine and a catalytic amount of sodium cyanide.
I have done this on >100kg scale, yields >90%.

[chonfusion]

You don't say what kind of amide. But the best way is to heat the ester in a sealed tube with the amine and a catalytic amount of sodium cyanide.
I have done this on >100kg scale, yields >90%.
[/quote]


At what temperature for the reaction, may I ask? Thanks!

[discodermolide]

You don't say what kind of amide. But the best way is to heat the ester in a sealed tube with the amine and a catalytic amount of sodium cyanide.
I have done this on >100kg scale, yields >90%.

At what temperature for the reaction, may I ask? Thanks!
[/quote]

reflux or at least 100°C

[Curie-ous]

Hi,

I used an acyl anion experiment with DBU and 1,2,4-triazole and it worked very nice.

Org. Lett., 2009, 11(7), 1499-1502.

Let me know how you get on!