Hydrochloric Acid → Benzyl 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-2-carboxylate

HRID 510959Notes

Reaction equation

HRID 510959 reaction equation
[CH3:1][C:2]1([CH3:31])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[C:11]([C:21]([O:23][CH2:24][C:25]3[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=3)=[O:22])[N:12]([C:14](OC(C)(C)C)=O)[CH:13]=2)[O:3]1.Cl.[H-].[Na+].CI>C(Cl)Cl.O1CCOCC1>[CH3:14][N:12]1[CH:13]=[C:9]([B:4]2[O:3][C:2]([CH3:1])([CH3:31])[C:6]([CH3:8])([CH3:7])[O:5]2)[CH:10]=[C:11]1[C:21]([O:23][CH2:24][C:25]1[CH:26]=[CH:27][CH:28]=[CH:29][CH:30]=1)=[O:22]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 6328Methyl iodideHCID 24758Sodium hydrideHCID 594023871-(1,1-Dimethylethyl) 2-(phenylmethyl) 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-1,2-dicarboxylate

Product 1

HCID 59402364Benzyl 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-2-carboxylate

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 312751,4-DioxaneSolvent

Procedure

2-Benzyl 1-tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrrole-1,2-dicarboxylate (0.5 g) was dissolved in CH2Cl2 (1 mL) and then 4 N HCl in dioxane (1 mL) was added. The reaction was stirred at room temperature for 1 hour. The solvent was removed under vacuum. The residue was redissolved in DMF (4 mL). To the resulting solution was added NaH (60% dispersion in mineral oil, 0.08 g, 2.0 mmol) at 0° C. The reaction mixture was stirred at 0° C. for 10 minutes. Methyl iodide (0.11 mL, 2.0 mmol) was added and the reaction was stirred at room temperature for 3 hours. The reaction was quenched with sat. NH4Cl solution and then diluted with EtOAc. After separation of layers, the organic phase was washed with water (twice) and brine; dried over Na2SO4. The solvent was removed to provide the desired crude product which was used in the next step without further purification. LCMS calculated for C19H25BNO4 (M+H)+: m/z=342.2. found: 342.2.

Workup

  1. customThe solvent was removed under vacuum
  2. dissolutionThe residue was redissolved in DMF (4 mL)
  3. stirringThe reaction mixture was stirred at 0° C. for 10 minutes
  4. stirringthe reaction was stirred at room temperature for 3 hours
  5. customThe reaction was quenched with sat. NH4Cl solution
  6. additiondiluted with EtOAc
  7. customAfter separation of layers
  8. washthe organic phase was washed with water (twice) and brine
  9. dry with materialdried over Na2SO4
  10. customThe solvent was removed

Sources & evidence

ORD record
ord-e9236be65f6947e98d6b80dd81f25cd3
Source dataset
uspto-grants-2015_08
Patent number
US09096600B2

Reaction notes

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