Which of the following tripeptides is formed when serine is treated with (Boc)₂O and threonine is treated with benzyl alcohol/acid first and the resulting intermediates are reacted in the presence of DCC followed by treatment with aqueous NaOH. The dipeptide is then reacted with the benzyl ester of isoleucine in the presence of DCC followed by treatment with trifluoroacetic acid and then aqueous NaOH?

Question

Quizplus · Accepted Answer

Starting with serine and (Boc)₂O, we can form the dipeptide Ser-Tyr by reacting the protected tyrosine with the unprotected serine. Starting with threonine and benzyl alcohol/acid, we can form the benzyl ester of threonine, which can react with the unprotected serine to form the dipeptide Ser-Thr. Next, we can react the dipeptide Ser-Thr with the benzyl ester of isoleucine in the presence of DCC to form the tripeptide. After removing the protecting groups with trifluoroacetic acid and aqueous NaOH, we get the final product Ser-Thr-Ile.

Which of the Following Tripeptides Is Formed When Serine Is