Sciencemadness Discussion Board

N-Acetylation of taurine

CrimpJiggler - 11-4-2013 at 18:15

Heres taurine:

and heres acamprosate, its acetylated analogue:


From what I read, esters can be used instead of acid anhydrides or acyl halides for N-acylations. So if one were to reflux a solution of taurine in ethyl acetate, would acamprosate and ethanol be produced?

Prometheus23 - 12-4-2013 at 08:10

Esters can indeed be used to n-acylate amines. Ethyl acetate would probably work fine, and even esters like aspirin can sometimes be used.

The only probably is that acamprosate is not n-acetyltaurine but n-acetylhomotaurine. So you would need to use homotaurine instead of taurine for the synthesis.

DraconicAcid - 12-4-2013 at 08:33

Taurine, however, is not HOS(O)2CH2CH2NH2 (as you've drawn it), but the zwitterion -O3SCH2CH2NH3+, with a negative charge on the sulphate end and a positive charge on the nitrogen. I expect that you'd need to deprotonate the nitrogen before it reacted with the ester.

[Edited on 12-4-2013 by DraconicAcid]

unionised - 12-4-2013 at 08:45

I wonder if ethyl acetate would be likely to acetlyate the nitrogen or ethylate the sulphonic acid.

DraconicAcid - 12-4-2013 at 08:50

Quote: Originally posted by unionised  
I wonder if ethyl acetate would be likely to acetlyate the nitrogen or ethylate the sulphonic acid.

If you had the anion, the nitrogen would be far more nucleophilic than the sulphate end. I don't think the acetyl-sulphate compound would form (and if it did, it would be very reactive towards nucleophiles).

Prometheus23 - 12-4-2013 at 08:57

Yes the taurine or homotaurine would obviously need to be in the anionic state to react with ethyl acetate. And I agree with DraconicAcid, I don't think the sulfonate group would react with the ethyl acetate to any appreciable amount.

CrimpJiggler - 12-4-2013 at 11:23

Whoops, I didn't notice that extra carbon in acamprosate. Homotaurine isn't as readily available as taurine.

ScienceSquirrel - 16-4-2013 at 04:06

Homotaurine is cheaply and readily made;

http://www.nrcresearchpress.com/doi/pdf/10.1139/v62-339