Reacción #921

Ecuación de reacción

ammonium chloride

n-butyllithium

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

N,N-dimethylcarbamyl chloride

HCl

→

title compound

Rendimiento 50.2%

3-[[-(1,1-Dimethylethyl)amino]sulfonyl]-N,N,1-trimethyl-1H-pyrrole-2-carboxamide

Rendimiento 50.2%

Disolventes

—

hexanes

THF

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   Temperaturato maintain the temperature below -65° C
3. 3
   Temperaturato warm to room temperature
4. 4
   workup.STIRRINGstir for ca. 1.5 hours
5. 5
   TemperaturaThe reaction mixture was cooled to ca. 5° C.
6. 6
   workup.STIRRINGThe reaction mixture was stirred for ca. 15 minutes
7. 7
   Otrothe aqueous phase was separated from the THF phase
8. 8
   Extracciónextracted with ethyl acetate
9. 9
   LavadoThe combined THF and ethyl acetate extracts were washed with brine
10. 10
    Secadodried (MgSO4)
11. 11
    Concentraciónconcentrated in vacuo to an oil
12. 12
    OtroThe oil was chromatographed on silica with (20% ethyl acetate/80% n-butyl chloride)

Procedimiento

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 a nitrogen atmosphere cooled to -78° C. was added dropwise, at such a rate as to keep the temperature below -60° C., 25 mL (61.5 mmol) 2.46M n-butyllithium in hexanes. The reaction mixture was stirred at -78° C. for ca. 30 minutes. To the reaction mixture was added dropwise a solution of 3.1 mL (33 mmol) of N,N-dimethylcarbamyl chloride in 10 mL of THF at such a rate as to maintain the temperature below -65° C. The reaction mixture was allowed to warm to room temperature and stir for ca. 1.5 hours. The reaction mixture was cooled to ca. 5° C. and 60 mL of 50% ammonium chloride solution was added. The reaction mixture was stirred for ca. 15 minutes. The pH was adjusted to ca. 3 with 1N HCl (ca. 30 mL), and the aqueous phase was separated from the THF phase and extracted with ethyl acetate. The combined THF and ethyl acetate extracts were washed with brine, dried (MgSO4) and concentrated in vacuo to an oil. The oil was chromatographed on silica with (20% ethyl acetate/80% n-butyl chloride) affording 4.33 g of the title compound as a pale yellow solid.

Fuente