4-Toluenesulfonyl chloride → 3-(2-Azidoethyl)thiophene

Participants

Reaction Conditions

Reaction Steps

2-(3-Thienyl)ethyl alcohol (2.62 g, 20.4 mmol) was dissolved in DCM (100 mL) and cooled to 0° C. After addition of triethylamine (3.10 g, 30.6 mmol) and solid tosyl chloride (3.89 g, 20.4 mmol), the reaction was stirred at room temperature overnight. DCM was evaporated, the mixture was diluted with EtOAc and washed subsequently with aqueous hydrochloric acid (1 N), water, saturated sodium hydrogen carbonate and brine. Drying and evaporation afforded an oil, which was dissolved in anhydrous DMF (20 mL). Sodium azide (2.65 g, 40.8 mmol) was added and the mixture heated to 40° C. for 3 h. After cooling to room temperature, EtOAc was added and the solution was washed with water (4×) and brine, then dried and evaporated. The resulting oil was filtered over silica gel (100 g) with the aid of PE/EtbAc (10:1) to obtain 2-(3-thienyl)ethyl azide (2.45 g, 78% ) as a colorless liquid. 1H-NMR (CDCl3) δ 7.3 (dd, J=2.9, 4.9 Hz, 1 H), 7.07 (m, 1 H), 6.98 (dd, J=1.2, 4.9 Hz, 1 H), 3.51 (t, J=7.1 Hz, 2 H), 2.94 (t, J=7.1 Hz, 2 H).

Provenance & Evidence