Model Reactions for the Biosynthesis of Thyroxine. V. Reaction of 4-Hydroxy-3-iodophenylpyruvic Acid and of 4-Hydroxy-3,5-diiodophenylpyruvic Acid with L-Tyrosine or Its Iodinated Congeners. A Novel Synthesis of 3,3',5'-Triiodo-L-thyronine^1,2