Réaction #909

Équation de réaction

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

Solvants

THF

—

hexanes

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONwas added dropwise at such a rate as
2. 2
   Autrethe temperature below -65° C
3. 3
   Températureto warm to room temperature
4. 4
   workup.STIRRINGstirred for ca. 1.5 hours
5. 5
   Températurewas cooled to 0° C.
6. 6
   AutreThe THF phase was separated
7. 7
   Lavagewashed with brine
8. 8
   Séchagedried (MgSO4)
9. 9
   Concentrationconcentrated to an ember oil
10. 10
    AutreThe NMR of the crude reaction product

Mode opératoire

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.

Source