Reaction #7053

Reaction equation

methyl alcohol

dimethylformamide

water

ethyl acetate

5-bromothiophene-2-sulfonamide

dimethylformamide

→

title compound

5-(Cyano)thiophene-2-sulfonamide

Solvents

methylene chloride

Conditions

Workup

1. 1
   workup.WAITplaced under microwave radiation (under nitrogen atmosphere at 160° C.) for 37 min
2. 2
   OtherThe organic phase is separated
3. 3
   Extractionthe aqueous layer is extracted with 20 mL ethyl acetate
4. 4
   DryingThe combined organic layers are dried over sodium sulfate
5. 5
   Concentrationconcentrated in vacuo
6. 6
   Otherchromatographed on silica (0–5% methyl alcohol in methylene chloride)

Procedure

A mixture of 5-bromothiophene-2-sulfonamide (0.50 g, 2.1 mmol), zinc cyanide (0.25 g, 2.1 mmol), tetrakis(triphenylphosphine)palladium(0) (0.072 g, 0.06 mmol) in dimethylformamide (5 mL, anhydrous) is placed under microwave radiation (under nitrogen atmosphere, 160° C.) for 15 min. Thin layer chromatography (5% methyl alcohol in methylene chloride) demonstrates the reaction is incomplete. Additional tetrakis-(triphenylphosphine)palladium(0) (0.24 g, 0.2 mmol) and dimethylformamide (10 mL) are added to the reaction mixture and placed under microwave radiation (under nitrogen atmosphere at 160° C.) for 37 min. 10 mL of water and 20 mL of ethyl acetate are added to the reaction mixture. The organic phase is separated and the aqueous layer is extracted with 20 mL ethyl acetate. The combined organic layers are dried over sodium sulfate, concentrated in vacuo, and then chromatographed on silica (0–5% methyl alcohol in methylene chloride) to give the title compound, as a white solid (0.22 g, 57% yield).

Source