Sodium Azide → 5-Chloro-4-nitrothiophene-2-carbonyl azide

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Reaction Steps

oxalyl chloride (460 mg, 3.62 mmol) followed by N,N-dimethylformide (0.05 mL) was added to a solution of 5-chloro-4-nitrothiophene-2-carboxylic acid (1.0 g, 14.0 mmol) in dichloromethane (20 mL) under nitrogen atmosphere and the resulting mixture was stirred at ambient temperature for 4 hours. TLC analysis showed no acid remaining so the mixture was allowed to be concentrated in vacuo. The resulting acid chloride was dissolved in dry tetrahydrofuran (10 mL). Sodium azide (190 mg, 2.89 mmol) was added to the above solution. The resulting mixture was stirred at ambient temperature for 10 hours. After this time, TLC analysis showed no acid chloride remaining so the mixture was diluted with ethyl acetate and washed with water and brine. The organic layer was separated, dried (Na2SO4), filtered and the solvent was removed to afford the title product as a brown solid (400 mg, 59% yield). 1H NMR (400 MHz, d6-DMSO) δ: 8.23 (2H, s).

Provenance & Evidence