Hydrochloric Acid → (2S,3S)-toluene-4-sulfonic acid 3-(3-tert-butyl-2-oxo-2,3-dihydro-benzimidazol-1-yl)-2-hydroxy-3-phenyl-propyl ester

HRID 2110387Notes

Reaction equation

HRID 2110387 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:19]2[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=2)[C@H:15]([OH:18])[CH2:16][OH:17])[C:6]1=[O:25])([CH3:4])([CH3:3])[CH3:2].[C:26]1([CH3:36])[CH:31]=[CH:30][C:29]([S:32](Cl)(=[O:34])=[O:33])=[CH:28][CH:27]=1.Cl>N1C=CC=CC=1>[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:19]2[CH:20]=[CH:21][CH:22]=[CH:23][CH:24]=2)[C@H:15]([OH:18])[CH2:16][O:17][S:32]([C:29]2[CH:30]=[CH:31][C:26]([CH3:36])=[CH:27][CH:28]=2)(=[O:34])=[O:33])[C:6]1=[O:25])([CH3:4])([CH3:2])[CH3:3]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 73974-Toluenesulfonyl chlorideHCID 442547721-tert-butyl-3-[(1S,2S)-2,3-dihydroxy-1-phenyl-propyl]-1,3-dihydro-2H-benzimidazol-2-one

Product 1

HCID 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

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

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. extractionextracted with ethyl acetate (50 mL)
  2. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  3. filtrationfiltered
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-f6714099c3c3449a8068db3bdfc83a57
Source dataset
uspto-grants-2009_04
Patent number
US07517899B2

Reaction notes

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