Synthesis and spectroscopic characterization of 5-diaminomethylidene barbiturates

the reaction of amines with dithiocyclohexylidenes is a general reaction for the synthesis of diaminomethylidene barbiturates. when diamines of the type h2n-(ch2)n-nh 2 are used as nucleophiles bicyclic compounds are the major reaction products, with yields increasing as n decreases, n = 2, 3, 4. when n = 6, macrocyclic compounds, novel 18 and 27 member rings, are obtained in very good yields. the 1h and 13c nmr assignment for all products is discussed.