Z-Glu(OtBu)-Val-Val-Glu(OtBu)-Glu(OtBu)-Ala-Glu(OtBu)-Asn-OtBu → H-Glu(OtBu)-Val-Val-Glu(OtBu)-Glu(OtBu)-Ala-Glu(OtBu)-Asn-OtBu

Participants

Reaction Steps

A solution of Z-Glu(OtBu)-Val-Val-Glu(OtBu)-Glu(OtBu)-Ala-Glu(OtBu)-Asn-OtBu 42.6 g; 32.0 mmol) in DMF (650 mL) containing 10% Pd-BaSO4 (15.0 g) was hydrogenated in a Vibromixer apparatus for 3 h. The reaction mixture was filtered through a bed of celite which was washed with DMF (5×250 mL). The combined filtrate was evaporated to 600 mL and DMSO (300 mL) added. The resultant solution was used fo the next stage of synthesis. A portion was evaporated to dryness, taken up in MeOH and precipitated with Et2O. The resultant gel was filtered, washed with Et2O and dried in vacuo; mp 246°-249° dec; [α]D25 -18.78° (c 1, DMF); Rf 0.78 (n-BuOH:AcOH:Pyr:H2O; 1-1-1-1). Anal. calc. for C57H99N9O18 (1198.46): C, 57.13; H, 8.33; N, 10.52. Found: C, 56.83; H, 8.32; N, 10.39.

Provenance & Evidence