반응 #77238

반응 방정식

2-chloro-5-nitrobenzoyl chloride

N-methylpyrrole

n-butyllithium

→

title compound

수율 19.2%

2-Chloro-5-nitrophenyl 1-methylpyrrol-2-yl ketone

수율 19.2%

용매

tetrahydrofuran

tetrahydrofuran

반응 조건

후처리

1. 1
   기타does not exceed −60° C
2. 2
   온도to warm to 0° C.
3. 3
   온도to warm to room temperature
4. 4
   workup.STIRRINGstirred overnight
5. 5
   기타quenched with 10% aqueous hydrochloric acid
6. 6
   추출the aqueous layer is extracted with ethyl acetate
7. 7
   세척washed with saturated sodium bicarbonate and brine
8. 8
   건조dried over anhydrous magnesium sulfate
9. 9
   농축Concentration in vacuo
10. 10
    기타affords a maroon gum, which
11. 11
    기타is chromatographed on silica gel with hexanes-ethyl acetate

실험 절차

To a mixture of n-butyllithium (2.5 M in hexanes, 100 ml, 0.250 mol) and tetrahydrofuran at room temperature is added N-methylpyrrole (40.6 g, 0.500 mol) dropwise over 30 minutes. The resultant mixture is stirred 90 minutes at 35-40° C. and cooled to −70° C. Zinc chloride (0.5 M in tetrahydrofuran, 500 ml, 0.25 mol) is added dropwise such that the temperature does not exceed −60° C. The resultant mixture is allowed to warm to 0° C. and stirred one hour at 0° C. A solution of 2-chloro-5-nitrobenzoyl chloride (60.5 g, 0.275 mol) in tetrahydrofuran is added, followed by tetrakis triphenylphosphine palladium (5.00 g). The resultant mixture is allowed to warm to room temperature, stirred overnight, and quenched with 10% aqueous hydrochloric acid. The organic layer is saved and the aqueous layer is extracted with ethyl acetate. The organic layers are combined, washed with saturated sodium bicarbonate and brine and dried over anhydrous magnesium sulfate. Concentration in vacuo affords a maroon gum, which is chromatographed on silica gel with hexanes-ethyl acetate to afford the title compound as a yellow solid (12.7 g, 19.2%, mp 108.5-109.5° C.) which is identified by IR and NMR spectral analysis. Using an essentially identical procedure and the appropriate heterocycle the following ketones are prepared:

출처