Reacción #56344

Ecuación de reacción

sodium chloride

L-thyroxine

trifluoroacetic acid

trifluoroacetic anhydride

→

thyroxine

N-Trifluoroacetylthyroxine

Disolventes

H2O

ethyl acetate

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroa suspension formed which
2. 2
   OtroThe organic phase of the mixture was separated
3. 3
   Lavadowashed with saturated aqueous sodium chloride solution
4. 4
   Secadodried over anhydrous magnesium sulfate
5. 5
   Filtraciónfiltered
6. 6
   Otroevaporated

Procedimiento

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).

Fuente