Dimethyl Sulfoxide → HCID 131711278, compound

Participants

Reaction Steps

Boc-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH (54.5 g, 61.7 mmol) was treated with HCl in THF (1.5 liters; 4.1 N; 40 min) and worked up as usual to give HCl.H-Thr(Bzl)-Ser(Bzl)-Ser(Bzl)-Glu(OBzl)-OH (46.3 g, 56.6 mmol) as a white powder. It was then stirred in DMF (500 ml) with Boc-Asp(OBzl)-OSu (23.7 g, 56 mmol) at 0° for 2 hours in the presence of Et3N (16 ml). The mixture was further stirred at 25° for 15 hours during which time 7.4 ml more of Et3N was added. The product was worked up as usual and crystallized from CH2Cl2 and petroleum ether: yield, 50.35 g (82.7%); mp 111°-113°; [α]D25 =+7.21° (c 1, DMSO).

Provenance & Evidence