N–N Ring Opening of Diazabicyclo[3.1.0]hexanes with Aryl Isocyanates and Isothiocyanates

Diazabicyclo[3.1.0]hexanes were shown to react selectively with three equivalents of aryl isocyanate to form 2,4-dioxo-N,1,3-triarylhexahydro-1H-pyrimido[1,2-a][1,3,5]triazine-9(2H)-carboxamides. Reaction with aryl isothiocyanates under similar conditions gives N1,N3-diaryldihydropyrimidine-1,3(2H,4H)-bis(carbothioamides). The addition of boron trifluoride etherate...