What precursor will produce this lithium thiol salt?

[nbritton]

Hi,

 

Does anyone know what lithium precursor is strong enough to pop off the hydrogens from di-hydro lipoic acid (DHLA)? Lipoic acid is normally a disulfide bond, DHLA is the reduced form with the disulfide bond cleaved to produce two free thiol groups.

 

The following is the structure of the compound I would like to make, it's simply DHLA with the hydrogen bonds replaced with lithium:

 

C(CCC(=O)[O-].[Li+])CC(CC[s-])[s-].[Li+].[Li+]

 

 

I tried lithium hydroxide and a white precipitate formed. However, I think this was merely lithium carbonate: 2LiOH + CO2 -> Li2CO3 + H2O. For both of the thiols in DHLA, they reportedly have a pKa of 10.7 (25C).

 

Thanks.

 

Anyone want to take a stab at this one?:

 

C(CCC(=O)[O-].[Li+])CC(CC[s-])[s-].[Mg++]

 

 

Edited January 11, 2014 by nbritton

[nbritton]

What would the pH be if you added 4 grams of elemental lithium to 600 mL of distilled water? With a pKa of 10.7, it appears I may not have had enough lithium hydroxide to deprotonate the thiol groups. I suppose the more relevant question is how much lithium hydroxide do I need to deprotonate, 1 gram, dihydro-lipoic acid in a solution of, 100 mL, distilled water?