[falcon]

Prompt please, how to synthesize 2-aminooxazolidinenone-4
One described method involve interaction a butyl ester of glycolic acid with urea, that results to 2-aminooxazolidinenone-4, but output of a product less than 5%.
I think, may be that there are more "fashionable" methods.

[movies]

How about urea + chloroacetyl chloride?

[falcon]

I have tried so to do, thus was formed
NH2CONHCOCH2Cl but chloromethyl - group did not attack the "urea" carbonyl (at least heating to ~120 `C). May be necessary iodoacetyl chloride (but...   is a very "cheerful" substance). Also I have lead reaction between urea and methyliodoacetate in DMF (isourea derivative -> intramolecular attack imino - group to ester group). I began to heat up and... iodine was allocated. May be air oxidation iodide anion in boiling solution  

[movies]

What conditions did you try to cyclize the product from the chloroacetyl chloride reaction?

How about a DCC coupling with urea and glycolic acid, then treat the product with tosyl chloride + triethylamine.  Procedures similar to that are the most common way to make oxazolines.

[falcon]

After neutralization NH2CONHCOCH2Cl*HCl,  heated up at presence NaHCO3 (is described method, but in cases saturated ureas) in ~50% EtOH, cyclization failed. At now I think that It is necessary to use (can be) stronger bases (KOtBu or KOiPr) in DMSO.
As to glycolic acid... is a problem for me. I think to try so: NH2CONHCOCH2Cl -> NH2CONHCOCH2OH ->
as you have offered (MsCl/Et3N).

[movies]

Maybe you could try urea + bromoacetyl bromide.  That should be significantly more reactive than the chloride version.

[falcon]

Well, I shall try so to make. Probably this substance should be heated up to ~ 120-150 `C.
About results I shall inform