Ap. Molchanov et al., Reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with aryl isocyanates and aryl isothiocyanates, SYNLETT, (12), 2000, pp. 1779-1780
Heating 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in the presence of aryl isocy
anates or aryl isothiocyanates leads to the formation of the corresponding
2,3-diarylperhydropyrazolo[1,2-a][1,2,4]triazol-1-one or 2,3-diarylperhydro
pyrazolo [1,2-a][1,2,4]triazol-1 -thione in good yield as a result of 1,3-d
ipolar cycloaddition of isocyanate (isothiocyanate) to an initially formed
ylide.