Reaction SMILES: [CH2:1]([S:3][S:4][C:5]1[CH:10]=[CH:9][CH:8]=[C:7]([CH3:11])[C:6]=1[OH:12])[CH3:2].C(=NC(C)C)=NC(C)C.[CH2:22]([C@@H:29]([C:86](=[O:150])[NH:87][CH2:88][C:89](=[O:149])[N:90]([CH3:148])[C@@H:91]([CH2:144][CH:145]([CH3:147])[CH3:146])[C:92](=[O:143])[N:93]([CH3:142])[C@@H:94]([CH:139]([CH3:141])[CH3:140])[C:95](=[O:138])[NH:96][C@@H:97]([CH2:131][C:132]1[CH:137]=[CH:136][CH:135]=[CH:134][CH:133]=1)[C:98](=[O:130])[NH:99][C@H:100]([C:105](=[O:129])[N:106]([CH3:128])[C@@H:107]([CH2:121][C:122]1[CH:127]=[CH:126][CH:125]=[CH:124][CH:123]=1)[C:108](=[O:120])[NH:109][C@@H:110]([CH3:119])[C:111](=[O:118])[N:112]1[CH2:117][CH2:116][CH2:115][CH2:114][CH2:113]1)[CH2:101][C:102](O)=[O:103])[N:30]([CH3:85])[C:31](=[O:84])[C@H:32]([C@H:62]([O:64][C:65]([C:78]1[CH:83]=[CH:82][CH:81]=[CH:80][CH:79]=1)([C:72]1[CH:77]=[CH:76][CH:75]=[CH:74][CH:73]=1)[C:66]1[CH:71]=[CH:70][CH:69]=[CH:68][CH:67]=1)[CH3:63])[NH:33][C:34](=[O:61])[C@H:35]([CH2:57][CH:58]([CH3:60])[CH3:59])[N:36]([CH3:56])[C:37](=[O:55])[C@H:38]([CH:52]([CH3:54])[CH3:53])[NH:39][C:40](=[O:51])[C@H:41]([CH3:50])[NH:42][C:43](=[O:49])[O:44][C:45]([CH3:48])([CH3:47])[CH3:46])[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1>CN(C)C1C=CN=CC=1.ClCCl>[CH2:22]([C@@H:29]([C:86](=[O:150])[NH:87][CH2:88][C:89](=[O:149])[N:90]([CH3:148])[C@@H:91]([CH2:144][CH:145]([CH3:147])[CH3:146])[C:92](=[O:143])[N:93]([CH3:142])[C@@H:94]([CH:139]([CH3:141])[CH3:140])[C:95](=[O:138])[NH:96][C@@H:97]([CH2:131][C:132]1[CH:137]=[CH:136][CH:135]=[CH:134][CH:133]=1)[C:98](=[O:130])[NH:99][C@H:100]([C:105](=[O:129])[N:106]([CH3:128])[C@@H:107]([CH2:121][C:122]1[CH:123]=[CH:124][CH:125]=[CH:126][CH:127]=1)[C:108](=[O:120])[NH:109][C@@H:110]([CH3:119])[C:111](=[O:118])[N:112]1[CH2:117][CH2:116][CH2:115][CH2:114][CH2:113]1)[CH2:101][C:102]([O:12][C:6]1[C:7]([CH3:11])=[CH:8][CH:9]=[CH:10][C:5]=1[S:4][S:3][CH2:1][CH3:2])=[O:103])[N:30]([CH3:85])[C:31](=[O:84])[C@H:32]([C@H:62]([O:64][C:65]([C:66]1[CH:71]=[CH:70][CH:69]=[CH:68][CH:67]=1)([C:72]1[CH:73]=[CH:74][CH:75]=[CH:76][CH:77]=1)[C:78]1[CH:83]=[CH:82][CH:81]=[CH:80][CH:79]=1)[CH3:63])[NH:33][C:34](=[O:61])[C@H:35]([CH2:57][CH:58]([CH3:60])[CH3:59])[N:36]([CH3:56])[C:37](=[O:55])[C@H:38]([CH:52]([CH3:54])[CH3:53])[NH:39][C:40](=[O:51])[C@H:41]([CH3:50])[NH:42][C:43](=[O:49])[O:44][C:45]([CH3:46])([CH3:47])[CH3:48])[C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1
Reactant: CC(C)C[C@@H](C(=O)N(C)[C@H](C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](CC(=O)O)C(=O)N(C)[C@@H](Cc1ccccc1)C(=O)N[C@@H](C)C(=O)N1CCCCC1)C(C)C)N(C)C(=O)CNC(=O)[C@H](Cc1ccccc1)N(C)C(=O)[C@@H](NC(=O)[C@H](CC(C)C)N(C)C(=O)[C@@H](NC(=O)[C@H](C)NC(=O)OC(C)(C)C)C(C)C)[C@@H](C)OC(c1ccccc1)(c1ccccc1)c1ccccc1
Reactant: CCSSc1cccc(C)c1O
Agent: CC(C)N=C=NC(C)C
Agent: CN(C)c1ccncc1
Solvent: ClCCl
Product: CCSSc1cccc(C)c1OC(=O)C[C@H](NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](C(C)C)N(C)C(=O)[C@H](CC(C)C)N(C)C(=O)CNC(=O)[C@H](Cc1ccccc1)N(C)C(=O)[C@@H](NC(=O)[C@H](CC(C)C)N(C)C(=O)[C@@H](NC(=O)[C@H](C)NC(=O)OC(C)(C)C)C(C)C)[C@@H](C)OC(c1ccccc1)(c1ccccc1)c1ccccc1)C(=O)N(C)[C@@H](Cc1ccccc1)C(=O)N[C@@H](C)C(=O)N1CCCCC1
Temperature: 25 °C
Reaction time: 8 h
Yield: 80 %

Procedure:
2-(Ethyldisulfanyl)-6-methylphenol separately synthesized according to a conventional method (J. AM. CHEM. SOC. 2009, 131, 5432-5437) (10.3 mg, 0.051 mmol), N,N′-methanediylidenebis(propan-2-amine) (8.0 ul, 0.051 mmol) and N,N-dimethylpyridin-4-amine (4.2 mg, 0.034 mmol) were added to a solution of (6S,9S,12S,15S,18S,24S,27S,30S,33S)-18,30-dibenzyl-12,24-diisobutyl-9,27-diisopropyl-2,2,6,11,17,23,26-heptamethyl-33-(methyl((S)-1-oxo-1-(((S)-1-oxo-1-(piperidin-1-yl)propan-2-yl)amino)-3-phenylpropan-2-yl)carbamoyl)-4,7,10,13,16,19,22,25,28,31-decaoxo-15-((R)-1-(trityloxy)ethyl)-3-oxa-5,8,11,14,17,20,23,26,29,32-decaazapentatriacontan-35-oic acid (Boc-Ala-Val-MeLeu-Thr(Trt)-MePhe-Gly-MeLeu-MeVal-Phe-Asp-MePhe-Ala-piperidine, 60.9 mg, 0.034 mmol) synthesized by peptide synthesis by the Fmoc method previously described using Boc amino acid in place of Fmoc amino acid at the N-terminal in dichloromethane (300 ul), and the mixture was stirred at room temperature overnight. The reaction solution was then concentrated under reduced pressure and purified by reverse phase silica gel column chromatography (10 mM aqueous ammonium acetate solution/methanol=70/30→0/100) to afford 2-(ethyldisulfanyl)-6-methylphenyl (6S,9S,12S,15S,18S,24S,27S,30S,33S)-18,30-dibenzyl-12,24-diisobutyl-9,27-diisopropyl-2,2,6,11,17,23,26-heptamethyl-33-(methyl((S)-1-oxo-1-(((S)-1-oxo-1-(piperidin-1-yl)propan-2-yl)amino)-3-phenylpropan-2-yl)carbamoyl)-4,7,10,13,16,19,22,25,28,31-decaoxo-15-((R)-1-(trityloxy)ethyl)-3-oxa-5,8,11,14,17,20,23,26,29,32-decaazapentatriacontan-35-oate (Compound P-138) (53.8 mg, 80%).