反応 #924

反応方程式

methyl chloroformate

N-(1,1-dimethylethyl)-1-methyl-1H-pyrrole-2-sulfonamide

n-butyllithium

→

title compound

収率 14.3%

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

収率 14.3%

溶媒

THF

ethyl acetate

THF

反応条件

後処理

1. 1
   その他the temperature below -58° C
2. 2
   その他1 h
3. 3
   その他at 0° C.
4. 4
   その他was recooled to -70° C.
5. 5
   workup.STIRRINGThe reaction mixture was stirred overnight at ambient temperature
6. 6
   洗浄This solution was washed successively with two 60 mL portions of 1N HCl, brine
7. 7
   乾燥dried (Na2SO4)
8. 8
   その他evaporated to a dark oil
9. 9
   その他The crude product was purified by chromatography on silica gel (30% ethyl acetate/70% hexanes)
10. 10
    その他then collected from hexanes

実験手順

To a solution of 2.5 g (11.5 mmol) of N-(1,1-dimethylethyl)-1-methyl-1H-pyrrole-2-sulfonamide in 50 mL THF under nitrogen atmosphere cooled to below -70° C. was added dropwise 13 mL (32.5 mmol) of 2.5M n-butyllithium at such a rate as to keep the temperature below -58° C. After stirring at -20° C. to -10° C. for 30 min then 1 h at 0° C., the mixture was recooled to -70° C. and treated with a solution of 1.63 g (17.3 mmol) of methyl chloroformate in 6 mL THF causing an exotherm to -57° C. The reaction mixture was stirred overnight at ambient temperature then diluted with 200 mL of ethyl acetate. This solution was washed successively with two 60 mL portions of 1N HCl, brine, then dried (Na2SO4) and evaporated to a dark oil. The crude product was purified by chromatography on silica gel (30% ethyl acetate/70% hexanes) then collected from hexanes to afford 0.45 g of the title compound, m.p. 105°-108° C.

出典