[NH:1]([C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])[C@H:2]([C:6]([OH:8])=O)[CH2:3][CH2:4][CH3:5].C1CCC(NC2CCCCC2)CC1.[NH2:29][C@H:30]([C:35]([O:37][CH3:38])=[O:36])[CH2:31][CH2:32][S:33][CH3:34].Cl.C(N(CC)CC)C.C1CCC(N=C=NC2CCCCC2)CC1>C(Cl)(Cl)Cl>[NH:1]([C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])[C@H:2]([C:6]([NH:29][C@H:30]([C:35]([O:37][CH3:38])=[O:36])[CH2:31][CH2:32][S:33][CH3:34])=[O:8])[CH2:3][CH2:4][CH3:5]BOC-Nva-OH, liberated from 4.78 g (12 mmoles) of the DCHA salt as described in Step 1 of Example 4, and 2.6 g (13 mmoles) of H-Met-OMe.HCl are dissolved in 40 ml of chloroform, and 1.82 ml (13 mmoles) of triethylamine are added. The mixture is cooled with ice, and a solution of 2.58 g (12.5 mmoles) of DCC in 20 ml of chloroform is added under stirring. The reaction mixture is allowed to stand at 5° C. overnight, thereafter the separated DCU is filtered off. The filtrate is washed thrice with 20 ml of n hydrochloric acid, each, thrice with 20 ml of n sodium hydrocarbonate solution, each, and then with 20 ml of water, dried over anhydrous sodium sulfate, and evaporated. The oily residue is crystallized from petroleum ether, and the resulting 3.42 g of crude product is recrystallized from a mixture of ethyl acetate and petroleum ether. 3.08 g (71%) of BOC-Nva-Met-OMe are obtained; m.p.: 69°- 70° C., Rf2 =0.81, [α]D25 =-42.7° (c=1%, in methanol).
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