Dimethylformamide → 2,1,3-Benzoxadiazole-5-carbonyl chloride

Participants

Reaction Steps

In a 500 ml reactor fitted with mechanical stirring, thermometer, addition funnel, reflux condenser and nitrogen inlet, 2,1,3-benzoxadiazole-5-carboxylic acid (28 g) was suspended in toluene (245 ml). To this suspension was added thionyl chloride (39.4 g) and DMF (0.35 ml). The resulting mixture was heated to reflux and maintained for 3 hours. A short pass column was installed and toluene was distilled (atmospheric pressure, 124 ml) off to remove excess reagent. After cooling the remaining toluene was distilled off, which resulted in a thick oil. This oil was distilled (90° C., 2 mm Hg) to remove impurities and the product crystallized on standing (79.8% yield), mp: 55-58° C.

Provenance & Evidence