Formation of Cyclohexano[c]1,2,5-oxadiazole from 1,2-Cyclohexanedione Dioxime. An Attempted Beckmann Rearrangement with Thionyl Chloride in Liquid Sulfur Dioxide

An attempted Beckmann rearrangement of 1,2-cyclohexanedione dioxime with thionyl chloride in liquid sulfur dioxide resulted in the formation of cyclohexano [c] 1,2,5-oxadiazole in 70% yield. The structure of the oxadiazole was established by oxidation, reduction, and synthesis. The reason why the condensation was predominant over the rearrangement was discussed in comparison with the case of benzil dioxime.