On the structure of 1 : 1 adducts of mesoionic compounds with isocyanates

The reactions of the mesoionic species (1) with isocyanates yield the acylated mesoionic derivatives, formed via unstable cycloadducts, with thioisocyanates, reacting similarly; the products of reactions between other similar mesoionic systems and isocyanates, previously described as cycloadducts, are also shown to be acylated mesoionic compounds on the basis of their physical data.