Reaction #912

Reaction equation

HCl

n-butyllithium

N-(1,1-dimethylethyl)-1-methyl-1H-pyrrole-3-sulfonamide

dimethyldisulfide

→

title compound

Yield 58.8%

N-(1,1-Dimethylethyl)-1-methyl-2-(methylthio)-1H-pyrrole-3-sulfonamide

Yield 58.8%

Solvents

—

hexanes

THF

Conditions

Workup

1. 1
   workup.ADDITIONwas added dropwise at such a rate as
2. 2
   Otherthe temperature below -65° C
3. 3
   Otherthe resulting reaction mixture
4. 4
   Temperatureto warm to room temperature
5. 5
   workup.STIRRINGstir for ca. 1.5 hours
6. 6
   TemperatureThe reaction mixture was cooled to 0° C.
7. 7
   OtherThe THF phase was separated
8. 8
   Washwashed with brine
9. 9
   Dryingdried (MgSO4)
10. 10
    Concentrationconcentrated in vacuo
11. 11
    OtherThe crude residue was chromatographed on silica (20% ethyl acetate/80% hexanes)

Procedure

To a solution of 6.48 g (30 mmol) of N-(1,1-dimethylethyl)-1-methyl-1H-pyrrole-3-sulfonamide in 150 mL THF under nitrogen atmosphere cooled to -78° C. was added dropwise at such a rate as to keep the temperature below -65° C. 25.52 mL (61.5 mmol) 2.41M n-butyllithium in hexanes. The reaction was stirred at -78° C. for ca. 30 minutes. To the reaction mixture was added 2.97 mL (33 mmol) of dimethyldisulfide in one portion and the resulting reaction mixture was allowed to warm to room temperature and stir for ca. 1.5 hours. The reaction mixture was cooled to 0° C. and acidified with 1N HCl. The THF phase was separated washed with brine, dried (MgSO4) and concentrated in vacuo. The crude residue was chromatographed on silica (20% ethyl acetate/80% hexanes) affording 4.63 g of the title compound as an off white solid, m.p. 116°-119° C.

Source