Reaktion #910

Reaktionsgleichung

HCl

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

n-butyllithium

methyl chloroformate

→

title compound

Ausbeute 55.9%

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

Ausbeute 55.9%

Lösungsmittel

THF

—

hexanes

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   Temperaturto warm to room temperature
3. 3
   workup.STIRRINGstir for ca. 1.5 hours
4. 4
   Temperaturwas cooled to 0° C.
5. 5
   SonstigeThe THF phase was separated
6. 6
   Waschenwashed with brine
7. 7
   Trocknendried (MgSO4)
8. 8
   Einengenconcentrated to an amber oil
9. 9
   Sonstigechromatographed on silica (30% ethyl acetate/70% hexanes)

Vorschrift

To a solution of 5 g (23 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., 20 mL (47.4 mmol) 2.32M n-butyllithium in hexanes. The resulting amber turbid solution was stirred at -78° C. for ca. 30 minutes. 1.87 mL (24.3 mmol) of methyl chloroformate was add in one portion and the resulting gold reaction mixture was allowed to warm to room temperature and stir 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 amber oil. The oil was combined with the crude product from the previous example and chromatographed on silica (30% ethyl acetate/70% hexanes) affording 3.53 g of the title compound as a solid.

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