3-Cyanomethylthiophene

Chemical Properties

Uses

• (E)-3-phenyl-2-(3-thienyl) acrylonitrile
• (Z)-3-(4-methylphenyl)-2-(3-thienyl) acrylonitrile

Synthesis

34846-44-1

7677-24-9

13781-53-8

General procedure for the synthesis of 3-thiophene acetonitrile from 3-methylthiophene and trimethylcyanosilane: N-bromosuccinimide (NBS, 9.07 g, 50.9 mmol, 1 eq.) and azobisisobutyronitrile (AIBN, 836 mg, 5.1 mmol, 0.1 eq.) were added to 3-methylthiophene (5 g, 50.9 mmol, 1 eq.) in carbon tetrachloride ( CCl4, 20 mL) solution. The reaction mixture was refluxed for 1 hour. After completion of the reaction, it was cooled to room temperature and the solvent was removed by evaporation under reduced pressure. The residue was dissolved in anhydrous acetonitrile (40 mL). Trimethylcyanosilane (TMSCN, 20 mL, 153 mmol, 3 eq.) and tetrabutylammonium fluoride (TBAF, 1 M solution of THF, 153 mL, 153 mmol, 3 eq.) were added slowly and dropwise to the solution at 0 °C and under argon protection. The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the solvent was removed by evaporation under reduced pressure. The residue was purified by fast column chromatography (eluent: 5% ethyl acetate/cyclohexane) to afford the orange oily product 3-thiophene acetonitrile (4.06 g, 33 mmol, 65% overall yield in two steps). The product was characterized as follows: 1H NMR (300 MHz, CDCl3): δ 7.22 (dd, J = 5.0, 3.0 Hz, 1H), 7.10 (dd, J = 2.8, 1.1 Hz, 1H), 6.90 (dd, J = 5.0, 1.2 Hz, 1H), 3.58 (s, 2H) ppm; 13C NMR (100 MHz CDCl3): δ 129.4, 127.0, 126.9, 122.9, 117.7, 18.4 ppm; IR (neat): ν 3104, 2360, 2340, 2255, 1688, 1415, 832, 771, 692 cm-1; GC-MS: m/z C6H5NS [M+] 122.

References