[swordlord]

i wanna synthesize  12-(1-carboxyethylamino)-12-oxododecanoic acid, from dodecanedioic acid and alanine.

what i've thinking of is: firstly using thionyl chloride(SOCl2) to turn odecanedioic acid into  dodecanedioyl dichloride, then  into the latter alanine be added.

How can i guarantee only one carboxy group of dodecanedioic acid reacts with alanine(i think it may be impossible, so what can i do to make it the major product)?

How should alanine been preprocessed?(ie. is it necessary for the carboxyl group of alanie to be protected, for example using bzl)?

Any suggestion is appriciated! thank u fellows

[sjb]

Can you make (or buy) the anhydride of the diacid? A similar example to an extent is in Clayden (p773, 1st edn), though this is succinic anhydride (5 membered ring)...?

You may need to protect the CO2H of alanine, perhaps as an ester?

S

[Sam (NG)]

Protect the carboxylic acid group of the amino acid using by converting it to a Benzyl Ester (OBn).

could use dicyclohexylcarbondiimide (DCC) and 1-hydroxybenzotriazole (HOBt) to link the two molecules.

Don't know how you get past the problem of protecting one side of a symmetrical molecule without using a different starting material that has two different ends.

@sjb, if you make the anhydride, won't it cyclise?

[sjb]

Hmm, good point!

I think you can selectively reduce an cyclic anhydride to the hydroxy-acid or simlar, so that will differentiate the two ends of the molecule - don't have my notes handy at the moment.

More digging in the files...

S