[Hypnotic drugs. 2. Reaction of guanidine carboxamide with fluorinated beta-diketones].

Since in the compound class of 2-ureidopyrimidines accessible through condensation of guanidinecarboxamide (1) with beta-diketones, representatives occur possessing hypnotic activity, the range of applicability of this synthesis on the one hand and the properties of the end products as related to their substitution pattern on the other have been investigated further. Thus, it was found tht while condensations of 1 with beta-diketones carrying short-chain fluorinated substituents proceed at room temperature, change to chain elongation requires more drastic reaction conditions. The interaction of 1 with 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione (2) requiring a reaction time of 2 h and a reaction temperature of 80 degrees C results in carbamoylguanidinium 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4-octen-6-one-4-olate (3).