Elongation of the peptide chain
Elongation of the peptide chain was based on deprotection
and acylation reactions. The reaction of activation
of α-carboxyl group of N-protected amino acids was carried
out using high purity coupling agents: DIC and HOBt
using a threefold excess of AA. The acylation reaction lasted
120 min, and then the resulting mixture was washed
according to the scheme: DMF (3 × 2 min), DCM : DMF
(3 × 2 min) and DCM (3 × 2 min).