The resin was washed with
DCM (three times) and Distribution Media Format (DMF) (three times) and then allowed to swell
in DMF for 30 min. After draining the DMF solution out, a DMF
solution of the mixture of Fmoc-protected amino acid (0.6 equiv
relative to resin loading) and DiEA (3 equiv) was added to the resin
and shaken for 30 min at room temperature.