Reacción #909

Ecuación de reacción

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

Methyl chloroformate

HCl

n-butyllithium

→

title compound

Methyl 3-[[(1,1-dimethylethyl)amino]sulfonyl]-1-methyl-1H-pyrrole-2-carboxylate

Disolventes

THF

—

hexanes

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added dropwise at such a rate as
2. 2
   Otrothe temperature below -65° C
3. 3
   Temperaturato warm to room temperature
4. 4
   workup.STIRRINGstirred for ca. 1.5 hours
5. 5
   Temperaturawas cooled to 0° C.
6. 6
   OtroThe THF phase was separated
7. 7
   Lavadowashed with brine
8. 8
   Secadodried (MgSO4)
9. 9
   Concentraciónconcentrated to an ember oil
10. 10
    OtroThe NMR of the crude reaction product

Procedimiento

To a solution of I g (4.62 mol) 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 -65° C. 4.1 mL (9.48 mmol) 2.32M n-butyllithium in hexanes. The resulting amber turbid solution was stirred at -78° C. for ca. 30 minutes. Methyl chloroformate (0.37 mL, 4.86 mmol) was added in one portion and the resulting gold reaction mixture was allowed to warm to room temperature and stirred for ca. 1.5 hours. The gold reaction mixture was cooled to 0° C. and acidified with 1N HCl. The THF phase was separated washed with brine, dried (MgSO4) and concentrated to an ember oil. The NMR of the crude reaction product was consistent with the title compound, additionally the NMR indicated that a trace of the starting material was also present. The crude material was combined with the product from a similar reaction run on the scale described below and chromatographed to give the title compound.

Fuente