Studies on pyrimidine derivatives. Michael addition of β-nitrostyrenes to substituted 6-aminouracils

A series of 5-(2-nitro-l-phenyl)ethyluracils were obtained when β-nitrostyrenes were reacted with 1,3-di-methyl-6-substituted uracil derivatives, instead of cyclic compounds. The structures of the compounds 5, 6 , and 7 were proved by spectroscopic methods and their mass fragmentation patterns are discussed.