[NH:1](C(OC(C)(C)C)=O)[C@H:2]([C:11]([N:13]([CH3:38])[C@H:14]([C:18]([N:20]([CH3:37])[C@H:21]([C:34]([NH2:36])=[O:35])[CH2:22][C:23]1[CH:28]=[CH:27][C:26]([OH:29])=[C:25]([C:30]([CH3:33])([CH3:32])[CH3:31])[CH:24]=1)=[O:19])[CH:15]([CH3:17])[CH3:16])=[O:12])[CH2:3][C:4]1[CH:9]=[CH:8][C:7]([Cl:10])=[CH:6][CH:5]=1>C(Cl)Cl.C(O)(C(F)(F)F)=O>[NH2:1][C@H:2]([C:11]([N:13]([CH3:38])[C@H:14]([C:18]([N:20]([CH3:37])[C@H:21]([C:34]([NH2:36])=[O:35])[CH2:22][C:23]1[CH:28]=[CH:27][C:26]([OH:29])=[C:25]([C:30]([CH3:31])([CH3:32])[CH3:33])[CH:24]=1)=[O:19])[CH:15]([CH3:16])[CH3:17])=[O:12])[CH2:3][C:4]1[CH:5]=[CH:6][C:7]([Cl:10])=[CH:8][CH:9]=1To a solution of Boc-Phe(4-Cl)-N-Me-Val-N-Me-Tyr(3-tBu)-NH2 (0.45 g, 0.697 mmol) in methylene chloride (4 ml), TFA (3 ml) was added, stirred for 20 min. and evaporated to remove the solvent under reduced pressure. The thus obtained residue was mixed with a saturated aqueous NaHCO3 solution, and extracted with methylene chloride. The organic layer was dried over anhydrous sodium sulfate and evaporated to remove the solvent under reduced pressure; the thus obtained residue was subjected to silica gel column chromatography (developing solvent: chloroform:methanol:aqueous ammonia=30:1:0.1) to give Phe(4-Cl)-N-Me-Val-N-Me-Tyr(3-tBu)-NH2 (355 mg, 93%). EI-MS:544 and 546 (M+)
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