Methyl chloroformate → Boc-DTrp(COOMe)-OBzl

HRID 977526

Reaction equation

HRID 977526 reaction equation
[NH:1]([C:23]([O:25][C:26]([CH3:29])([CH3:28])[CH3:27])=[O:24])[C@@H:2]([C:13]([O:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)=[O:14])[CH2:3][C:4]1[C:12]2[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=2)[NH:6][CH:5]=1.Cl[C:31]([O:33][CH3:34])=[O:32].[OH-].[Na+]>ClCCl.CCCC[N+](CCCC)(CCCC)CCCC.OS([O-])(=O)=O>[NH:1]([C:23]([O:25][C:26]([CH3:29])([CH3:28])[CH3:27])=[O:24])[C@@H:2]([C:13]([O:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)=[O:14])[CH2:3][C:4]1[C:12]2[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=2)[N:6]([C:31]([O:33][CH3:34])=[O:32])[CH:5]=1

Participants

6

Reactant 3

HCID 6586Methyl chloroformateHCID 14798Sodium HydroxideHCID 10739405Boc-DTrp-OBzl

Product 1

HCID 10813513Boc-DTrp(COOMe)-OBzl

Reagents, catalysts & solvents 2

HCID 94433Tetrabutylammonium hydrogen sulfateCatalystHCID 6344DichloromethaneSolvent

Procedure

To a solution of Boc-DTrp-OBzl (12.19 g) in dichloromethane (60 ml) were added methyl chloroformate (4.8 ml), pulverized sodium hydroxide (4.1 g) and TBAHS (9.2 g), and the mixture was stirred at room temperature for 4 h. The reaction mixture was washed with water, dried over MgSO4 and evaporated in vacuo. The residue was crystallized from dichloromethane and hexane to give Boc-DTrp(COOMe)-OBzl (12.57 g). Boc-DTrp(COOMe)-OBzl (4.52 g) was dissolved in 4N-hydrogen chloride/1,4-dioxane (50 ml) and the mixture was stirred at room temperature for 45 min. Ethyl ether (50 ml) was added to the mixture to complete the precipitation. The precipitate was collected by filtration and dried in vacuo to give H-DTrp(COOMe)-OBzl.HCl (3.71 g). To a suspension of H-DTrp(COOMe)-OBzl.HCl (1.94 g) in dichloromethane (50 ml) were added NMM (0.55 ml), 2,6-dimethylpiperidinocarbonyl-γMeLeu-OH (1.42 g), HOBT.H2O (0.84 g) and EDCI.HCl (1.05 g) under ice cooling. The mixture was stirred at the same temperature for 2 h and at room temperature over night. The reaction mixture was washed with sat. aq NaHCO3 (50 ml), 10% aq. citric acid (50 ml) and brine (50 ml) successively, dried over MgSO4 and evaporated. The residue was purified by MPLC (Merck, LiChroprep Si 60) with hexane/ethyl acetate=2/1 for elution to give 2,6-dimethylpiperidinocarbonyl-γMeLeu-DTrp(COOMe)-OBzl (1.17 g). A solution of 2,6-dimethylpiperidinocarbonyl-γMeLeu-DTrp(COOMe)-OBzl (1.10 g) in methanol (30 ml) was hydrogenated over 10% Pd/C (50 mg) at an atmospheric pressure of hydrogen for 1.5 h. After removal of the catalyst by filtration, the filtrate was evaporated in vacuo to give the product (0.93 g).

Workup

  1. washThe reaction mixture was washed with water
  2. dry with materialdried over MgSO4
  3. customevaporated in vacuo
  4. customThe residue was crystallized from dichloromethane and hexane

Sources & evidence

ORD record
ord-075f753f987e4b8cb13bc3affb601854
Source dataset
uspto-grants-1997_03
Patent number
US05614498

Linked notes

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