Réaction #56344

Équation de réaction

sodium chloride

L-thyroxine

trifluoroacetic acid

trifluoroacetic anhydride

→

thyroxine

N-Trifluoroacetylthyroxine

Solvants

H2O

ethyl acetate

Conditions de réaction

Traitement

1. 1
   Autrea suspension formed which
2. 2
   AutreThe organic phase of the mixture was separated
3. 3
   Lavagewashed with saturated aqueous sodium chloride solution
4. 4
   Séchagedried over anhydrous magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Autreevaporated

Mode opératoire

A solution of 20 g [25.6 millimoles (mmol)] of L-thyroxine (Sigma Chemical Co., St. Louis, Missouri USA) in 240 ml of dry ethyl acetate containing 46 ml of trifluoroacetic acid and 7.6 ml of trifluoroacetic anhydride was stirred at 0° C. for one hour. Upon warming to room temperature and adding 200 ml of H2O, a suspension formed which was then saturated with sodium chloride. The organic phase of the mixture was separated, washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered and evaporated to give 21.3 g of the N-protected thyroxine derivative (6). A sample was recrystallized from ether-pentane to give fine crystals, m.p. 233°-235° C. (decomposed).

Source