[NH2:1][C@H:2]([C:4]([OH:6])=[O:5])[CH3:3].[NH:7]([C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])[C@H:8]([C:10](ON1C(=O)CCC1=O)=[O:11])[CH3:9].CN1CCOCC1>CN(C=O)C>[NH:7]([C:20]([O:22][C:23]([CH3:24])([CH3:26])[CH3:25])=[O:21])[C@H:8]([C:10]([NH:1][C@H:2]([C:4]([OH:6])=[O:5])[CH3:3])=[O:11])[CH3:9]L-Alanine (3.57 g, 40 mmol) was dissolved in 18.8 ml of Triton B (40 mmol), evaporated to dryness, and the oily residue re-evaporated twice with DMF (30 ml each). The salt obtained was stirred with 11.45 g of Boc-Ala-OSu (40 mmol) in 40 ml DMF, with 4 ml of NMM added, for 20 hours. The solvent was removed and the residue taken up in 10% HOAc (100 ml). The product was extracted into EtOAc (4 times 100 ml), washed twice with a small volume of H2O, dried over Na2SO4, evaporated to a small volume, and treated with petroleum ether until cloudiness developed. A crystalline product formed on storage in the refrigerator overnight: Yield, 8.2 g (76.3%); mp 115°-118°.
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