G. Mloston et al., Interception of a thiocarbonyl ylide by thiouracil and crystal structure of the 2 : 1 adduct, POL J CHEM, 73(7), 1999, pp. 1219-1225
The reaction of thiocarbonyl ylide 1, generated in situ by thermolysis of t
he corresponding 2,5-dihydro-1,3,4-thiadiazole, with a twofold excess of th
iouracil ( I) yielded a mixture of the 1:2 adduct 5 and the 1:1 adduct 6 in
a ratio of ca. 1:1. These interception products are formed by protonation
of 1 and nucleophilic addition via the S- or O-atom. The structure of 5 has
been established by X-ray crystallography.