Hydrochloric Acid → 1,2,5-Oxadiazole-3,4-dicarbonyl dichloride

Participants

Reaction Steps

In a glass reactor under a blanket of nitrogen was placed 120 ml of thionyl chloride and 15.8 g of 1,2,5-oxadiazole-3,4-dicarboxylic acid (Grundmann, Ber. 97 (2), 575-8, 1964). The mixture was heated to reflux and 0.5 ml of dimethylformamide was added. In the ensuing vigorous reaction HCl and SO2 were given off. Refluxing was continued for about 1 hour until all the free acid was dissolved. Excess thionyl chloride was removed at 50° C under vacuum and the residue distilled at 35° C/0.5 mm. Two redistillations gave 13.5 g of 1,2,5-oxadiazole-3,4-dicarbonyl chloride in the form of a colorless liquid boiling at 62°-64° C/9 mm. Infrared absorption at 1760 cm-1 (C=O) and at 1525 cm-1 and 1440 cm-1 (-C=N) was consistent with the proposed structure.

Provenance & Evidence