Construction of variant 3b wherein the Aib-3 residue of 1 is replaced by Ala is summarized in Scheme 5. Hydrogenolysis of the dipeptide Cbz-Ser-Ala-OMe ( ) was followed by coupling with dipeptide 13, furnishing tetrapeptide 17 in moderate yield. As in the coupling of 11, protection of the alcohol moiety in 16 was eschewed in favor of a short and direct synthetic route to 3b. Mesylation and elimination of the primary alcohol in 17 was lower-yielding than the analogous transformation of dipeptide 9 (see Scheme 2), as 3b was obtained in 36% yield.