Question

Propose a synthesis for obtaining alanine-tyrosine from alanine and tyrosine (free amino acids). Indicate which amino acid must be N-protected and C-protected. Indicate the reason for each of the steps.

Answer 1

Steps

a) protect the amino group in the N-terminal amino acid

b) protect the carboxyl group in the C-terminal amino acid

c) couple the two amino acids by forming the new amide bond

d) deprotect the terminal of the new peptide which were protected before.

Reason for protection: It masks specific functional group so that it will not interfere with required reaction.

Alanine - Cterminal terminal (cools (NH2 free) CHZEIT NN-CH, - NH Chacoon (cook of 1 group PL L Alanine Tyrosine / → To react cool group of Alanine with NHy of tyrosine. we need to protect NH₂ group of alanine of cool group

Nola group of - Protect / Block alanine;- СУгода » Reprene Си, осми-ра, сьор Р) -н-н-соор step II) Protect/Block or group 9 Тулья. MN-co-cool + Ron чо-н-а- о-в? Би и, чи, би

step 11) couple out to N-CH-cod 2 L I CH₂ A & Hy-on B-NH-CH " CHLOH step to reprotection / H2/12 I will deprotect & aq naon Ty Cz Og + H₂N-CH-G-NH-CH-cool & Hoon 3 it will deprotect cool grduf Vorut the N-CH-C H=CH-Cool + Ron Hyou