[NH2:1][CH2:2][C@H:3]([NH:7][C:8]([O:10][CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)=[O:9])[C:4]([OH:6])=[O:5].N#N.[CH3:20][C:21](=[CH2:23])[CH3:22].OS(O)(=O)=O.C([O-])(O)=O.[Na+]>C(OCC)C.O1CCOCC1>[NH2:1][CH2:2][C@H:3]([NH:7][C:8]([O:10][CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)=[O:9])[C:4]([O:6][C:21]([CH3:23])([CH3:22])[CH3:20])=[O:5]10 g (42 mmol) of (2S)-3-amino-2-benzyloxycarbonylaminopropionic acid are shaken in an autoclave for 3 days, at an N2 pressure of 20 atm., in a mixture consisting of 100 ml of dioxane, 100 ml of isobutylene and 8 ml of conc. H2SO4. Excess isobutylene is blown off and 150 ml of diethyl ether and 150 ml of a saturated solution of NaHCO3 are added to the remaining solution. The phases are separated and the aqueous phase is extracted twice with 100 ml of diethyl ether on each occasion. The combined organic phases are washed with 2×100 ml of H2O and dried over Na2SO4. 9.58 g (78%) of (1.6) are obtained as a pale yellow oil after the solvent has been removed in vacuo.
Wird geladen…
