3,4-Dimethyl-2-formyl-pyrrole-1-carboxylic acid tert-butyl ester → 3,4-Dimethyl-2-(1-hydroxy-prop-2-ynyl)-pyrrole-1-carboxylic acid tert-butyl ester

HRID 1861018Notes

Reaction equation

HRID 1861018 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH:12]=[C:11]([CH3:13])[C:10]([CH3:14])=[C:9]1[CH:15]=[O:16])=[O:7])([CH3:4])([CH3:3])[CH3:2].[C:17]([Mg]Cl)#[CH:18]>C1COCC1>[C:1]([O:5][C:6]([N:8]1[CH:12]=[C:11]([CH3:13])[C:10]([CH3:14])=[C:9]1[CH:15]([OH:16])[C:17]#[CH:18])=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

4

Reactant 2

HCID 865861033,4-Dimethyl-2-formyl-pyrrole-1-carboxylic acid tert-butyl esterHCID 178462451HCID 178462451, compound

Product 1

HCID 235502733,4-Dimethyl-2-(1-hydroxy-prop-2-ynyl)-pyrrole-1-carboxylic acid tert-butyl ester

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 3,4-dimethyl-2-formyl-pyrrole-1-carboxylic acid tert-butyl ester (3.18 g, 14.2 mmol) (prepared as described in Tietze et al., supra,) in dry THF(40 mL) was added ethynylmagnesium chloride (Aldrich, 0.5 M solution in THF, 57 mL, 28.5 mmol) dropwise at −65° C. and the reaction mixture was stirred at the same temperature for 0.5 hour. The cooling bath was then removed and the reaction mixture was stirred for another 2 hours to give a clear solution. The reaction was quenched by slowly adding EtOH (8 mL) and a saturated aqueous NH4Cl solution (26 mL) at 5° C. The mixture was extracted several times with ethyl acetate. The combined organic extract was washed with brine, dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. Flash chromatography (silica gel, 95:5 hexanes/ethyl acetate) purification of the crude oil afforded 3,4-dimethyl-2-(1-hydroxy-prop-2-ynyl)-pyrrole-1-carboxylic acid tert-butyl ester as a yellow oil. (Yield 3.54 g, 100.0%).

Workup

  1. customThe cooling bath was then removed
  2. stirringthe reaction mixture was stirred for another 2 hours
  3. customto give a clear solution
  4. customThe reaction was quenched by slowly adding EtOH (8 mL)
  5. customat 5° C
  6. extractionThe mixture was extracted several times with ethyl acetate
  7. extractionThe combined organic extract
  8. washwas washed with brine
  9. dry with materialdried over anhydrous magnesium sulfate
  10. filtrationfiltered
  11. concentrationconcentrated in vacuo
  12. customFlash chromatography (silica gel, 95:5 hexanes/ethyl acetate) purification of the crude oil

Sources & evidence

ORD record
ord-af1cdef41acf4fe6a4ada30a2d56e42e
Source dataset
uspto-grants-2003_03
Patent number
US06531598B1

Reaction notes

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