Sodium Azide → HCID 11778691, compound

Participants

Reaction Steps

To a solution of 2-carboxy-5-(4'-(1,1-dimethylethyl)phenyl)thiophene (11.42 g, 0.0439 mol), which was prepared according to this method described in European Patent Application 0 259 972, in ethyl acetate (125 mL) was added three drops of dimethylformamide and then stirred at room temperature. To this reaction mixture 1.2 equivalents of oxalyl chloride (20 mL) was added over a period of 15 minutes. The reaction mixture was then stirred at room temperature for 11/2 hours. The ethyl acetate was then removed under reduced pressure to afford a yellow solid, a compound of formula (H). The yellow solid was dissolved in methylene chloride (70 mL) and the resulting solution was cooled. To this solution tetrabutylammonium bromide (200 mg) was added and then an aqueous solution of sodium azide (4.0 g in 15 mL H2O) was added. The reaction mixture was stirred at 0° C. for 2 hours. The reaction mixture was then washed twice with water (150 mL) and then dried over magnesium sulfate. The product was then purified by chromatography on silica gel (400 g, elute with ethyl acetate/hexane (20/80)) and then recrystallized from t-butyl methyl ether and hexane to yield 3.64 g of 2-azidocarbonyl-5-(4'-(1,1-dimethylethyl)phenyl)thiophene, m.p. 162°-164.5° C.

Provenance & Evidence