Reaction SMILES: [NH:1]([C:111]([C:124]1[CH:129]=[CH:128][CH:127]=[CH:126][CH:125]=1)([C:118]1[CH:123]=[CH:122][CH:121]=[CH:120][CH:119]=1)[C:112]1[CH:117]=[CH:116][CH:115]=[CH:114][CH:113]=1)[C@H:2]([C:24]([NH:26][C@H:27]([C:35]([NH:37][C@H:38]([C:46]([NH:48][C@H:49]([C:56]([NH:58][C@H:59]([C:64]([NH:66][C@H:67]([C:89]([NH:91][C@H:92]([C:99]([NH:101][C@H:102]([C:107]([O:109]C)=[O:108])[CH2:103][CH:104]([CH3:106])[CH3:105])=[O:100])[CH2:93][O:94][C:95]([CH3:98])([CH3:97])[CH3:96])=[O:90])[CH2:68][S:69][C:70]([C:83]1[CH:88]=[CH:87][CH:86]=[CH:85][CH:84]=1)([C:77]1[CH:82]=[CH:81][CH:80]=[CH:79][CH:78]=1)[C:71]1[CH:76]=[CH:75][CH:74]=[CH:73][CH:72]=1)=[O:65])[C@H:60]([CH2:62][CH3:63])[CH3:61])=[O:57])[CH2:50][O:51][C:52]([CH3:55])([CH3:54])[CH3:53])=[O:47])[C@@H:39]([CH3:45])[O:40][C:41]([CH3:44])([CH3:43])[CH3:42])=[O:36])[CH2:28][S:29][CH2:30][NH:31][C:32]([CH3:34])=[O:33])=[O:25])[CH2:3][S:4][C:5]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)([C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.O.[OH-].[Na+].Cl>O1CCOCC1>[NH:1]([C:111]([C:124]1[CH:125]=[CH:126][CH:127]=[CH:128][CH:129]=1)([C:118]1[CH:119]=[CH:120][CH:121]=[CH:122][CH:123]=1)[C:112]1[CH:117]=[CH:116][CH:115]=[CH:114][CH:113]=1)[C@H:2]([C:24]([NH:26][C@H:27]([C:35]([NH:37][C@H:38]([C:46]([NH:48][C@H:49]([C:56]([NH:58][C@H:59]([C:64]([NH:66][C@H:67]([C:89]([NH:91][C@H:92]([C:99]([NH:101][C@H:102]([C:107]([OH:109])=[O:108])[CH2:103][CH:104]([CH3:106])[CH3:105])=[O:100])[CH2:93][O:94][C:95]([CH3:97])([CH3:96])[CH3:98])=[O:90])[CH2:68][S:69][C:70]([C:71]1[CH:72]=[CH:73][CH:74]=[CH:75][CH:76]=1)([C:77]1[CH:82]=[CH:81][CH:80]=[CH:79][CH:78]=1)[C:83]1[CH:84]=[CH:85][CH:86]=[CH:87][CH:88]=1)=[O:65])[C@H:60]([CH2:62][CH3:63])[CH3:61])=[O:57])[CH2:50][O:51][C:52]([CH3:53])([CH3:54])[CH3:55])=[O:47])[C@@H:39]([CH3:45])[O:40][C:41]([CH3:44])([CH3:43])[CH3:42])=[O:36])[CH2:28][S:29][CH2:30][NH:31][C:32]([CH3:34])=[O:33])=[O:25])[CH2:3][S:4][C:5]([C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)([C:6]1[CH:7]=[CH:8][CH:9]=[CH:10][CH:11]=1)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1
Reactant: CC[C@H](C)[C@H](NC(=O)[C@H](COC(C)(C)C)NC(=O)[C@@H](NC(=O)[C@H](CSCNC(C)=O)NC(=O)[C@H](CSC(c1ccccc1)(c1ccccc1)c1ccccc1)NC(c1ccccc1)(c1ccccc1)c1ccccc1)[C@@H](C)OC(C)(C)C)C(=O)N[C@@H](CSC(c1ccccc1)(c1ccccc1)c1ccccc1)C(=O)N[C@@H](COC(C)(C)C)C(=O)N[C@@H](CC(C)C)C(=O)OC
Agent: Cl
Agent: [Na+]
Agent: [OH-]
Solvent: C1COCCO1
Solvent: O
Product: CC[C@H](C)[C@H](NC(=O)[C@H](COC(C)(C)C)NC(=O)[C@@H](NC(=O)[C@H](CSCNC(C)=O)NC(=O)[C@H](CSC(c1ccccc1)(c1ccccc1)c1ccccc1)NC(c1ccccc1)(c1ccccc1)c1ccccc1)[C@@H](C)OC(C)(C)C)C(=O)N[C@@H](CSC(c1ccccc1)(c1ccccc1)c1ccccc1)C(=O)N[C@@H](COC(C)(C)C)C(=O)N[C@@H](CC(C)C)C(=O)O
Temperature: 0 °C

Procedure:
3.6 g of Trt-Cys(Trt)-Cys(Acm)-Thr(But)-Ser(But)-Ile-Cys(Trt)-Ser(But)-Leu-OMe are dissolved in 50 ml of dioxane and 17 ml of water and 4 ml of 1 N sodium hydroxide solution are added. After 1 hour at 20°C the mixture is cooled to 0°C and 4 ml of 1 N hydrochloric acid are added dropwise. The dioxane is then largely evaporated off at 20°C under reduced pressure, 20 ml of water are added and the precipitate is filtered off and dried over potassium hydroxide.