Citric Acid → tert-Butyl (4-ethynyl-2-nitrophenyl)carbamate

HRID 859287Notes

Reaction equation

HRID 859287 reaction equation
[C:1]([O:5][C:6](=[O:23])[NH:7][C:8]1[CH:13]=[CH:12][C:11]([C:14]#[C:15][Si](C)(C)C)=[CH:10][C:9]=1[N+:20]([O-:22])=[O:21])([CH3:4])([CH3:3])[CH3:2].[OH-].[Na+].C(O)(=O)CC(CC(O)=O)(C(O)=O)O>CO.C1COCC1>[C:1]([O:5][C:6](=[O:23])[NH:7][C:8]1[CH:13]=[CH:12][C:11]([C:14]#[CH:15])=[CH:10][C:9]=1[N+:20]([O-:22])=[O:21])([CH3:4])([CH3:2])[CH3:3]

Participants

6

Reactant 3

HCID 311Citric AcidHCID 14798Sodium HydroxideHCID 67289195(2-Nitro-4-trimethylsilanylethynyl-phenyl)-carbamic acid tert.-butyl ester

Product 1

HCID 23554338tert-Butyl (4-ethynyl-2-nitrophenyl)carbamateYield 86.3%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of (2-nitro-4-trimethylsilanylethynyl-phenyl)-carbamic acid tert.-butyl ester (Example F1) (3.54 g, 10.6 mmol) in MeOH (10 mL) and THF (20 mL) at 0° C. was added 1N NaOH (13 mL) and stirring was continued at 23° C. for 30 min. Poured into cold 5% citric acid, extracted with EtOAc (300 mL), washed with sat. NaHCO3-sol. and brine, dried over MgSO4. Removal of the solvent in vacuum left a dark brown oil, which was purified by silica gel column chromatography with hexane/EtOAc 19:1. Obtained as a yellow solid (2.4 g).

Workup

  1. extractionextracted with EtOAc (300 mL)
  2. washwashed with sat. NaHCO3-sol
  3. dry with materialand brine, dried over MgSO4
  4. customRemoval of the solvent in vacuum
  5. waitleft a dark brown oil, which
  6. customwas purified by silica gel column chromatography with hexane/EtOAc 19:1

Sources & evidence

ORD record
ord-073c7373f7cc4efb93f799e1881e4544
Source dataset
uspto-grants-2006_12
Patent number
US07151098B2

Reaction notes

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