Methylamine → 1-t-Butyl-3-[(1S,2R)-2-hydroxy-3-(methylamino)-1-phenylpropyl]-1,3-dihydro-2H-benzimidazol-2-one

HRID 2110388Notes

Reaction equation

HRID 2110388 reaction equation
[C:1]([N:5]1[C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=2[N:7]([C@@H:14]([C:29]2[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=2)[C@H:15]([OH:28])[CH2:16]OS(C2C=CC(C)=CC=2)(=O)=O)[C:6]1=[O:35])([CH3:4])([CH3:3])[CH3:2].[CH3:36][NH2:37]>CO>[C:1]([N:5]1[C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=2[N:7]([C@@H:14]([C:29]2[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=2)[C@H:15]([OH:28])[CH2:16][NH:37][CH3:36])[C:6]1=[O:35])([CH3:2])([CH3:4])[CH3:3]

Participants

4

Reactant 2

HCID 6329MethylamineHCID 87618528(2S,3S)-toluene-4-sulfonic acid 3-(3-tert-butyl-2-oxo-2,3-dihydro-benzimidazol-1-yl)-2-hydroxy-3-phenyl-propyl ester

Product 1

HCID 442550501-t-Butyl-3-[(1S,2R)-2-hydroxy-3-(methylamino)-1-phenylpropyl]-1,3-dihydro-2H-benzimidazol-2-one

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent2×

Procedure

A solution of 1-tert-butyl-3-[(1S,2S)-2,3-dihydroxy-1-phenyl-propyl]-1,3-dihydro-2H-benzimidazol-2-one (0.55 g, 1.6 mmol) and para-toluenesulfonyl chloride (0.37 g, 1.9 mmol) in anhydrous pyridine (5 mL) was stirred at room temperature under nitrogen for 12 hours. The reaction was poured into a cold 1N aqueous solution of hydrochloric acid (50 mL) and extracted with ethyl acetate (50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to give (2S,3S)-toluene-4-sulfonic acid 3-(3-tert-butyl-2-oxo-2,3-dihydro-benzimidazol-1-yl)-2-hydroxy-3-phenyl-propyl ester. To a solution of (2S,3S)-toluene-4-sulfonic acid 3-(3-tert-butyl-2-oxo-2,3-dihydro-benzimidazol-1-yl)-2-hydroxy-3-phenyl-propyl ester (0.8 g, 1.6 mmol) in methanol (10 mL) was added a 2N solution of methylamine in methanol (4 mL, 8 mmol) and the reaction mixture stirred for 12 hours at room temperature in a sealed tube. Upon completion, the reaction was partitioned between a saturated aqueous solution of sodium bicarbonate (50 mL) and ethyl acetate (50 mL). The organic layer was separated, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The residue was purified via flash column chromatography (silica, 20% MeOH in dichloromethane) to give 1-tert-butyl-3-[(1S,2R)-2-hydroxy-3-methylamino-1-phenylpropyl]-1,3-dihydro-2H-benzimidazol-2-one as a clear oil. The free base was dissolved in a minimum amount of ethanol and treated with a 2N ethereal solution of hydrochloric acid and stirred for 1 hour s. The ethanol was removed in vacuo and the clear oil was triturated with diethyl ether/dichloromethane to give 1-tert-butyl-3-[(1S,2R)-2-hydroxy-3-(methylamino)-1-phenylpropyl]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride as a white solid. HRMS: calcd for C21H27N3O2+H+, 354.21760. Found (ESI, [M+H]+), 354.2179.

Workup

  1. customUpon completion, the reaction was partitioned between a saturated aqueous solution of sodium bicarbonate (50 mL) and ethyl acetate (50 mL)
  2. customThe organic layer was separated
  3. dry with materialdried over anhydrous sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. customThe residue was purified via flash column chromatography (silica, 20% MeOH in dichloromethane)

Sources & evidence

ORD record
ord-dec28823bf9445318706cb2f85ad0f33
Source dataset
uspto-grants-2009_04
Patent number
US07517899B2

Reaction notes

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