[Synthesis of pyrido [1,2-a] pyrimidinone series of compounds, potential agents on the nervous system].

In an effort to modify the structure of edulinine so to seek compounds exhibiting higher potency toward inhibition of central nervous system, we designed and synthesized several analogous compounds: 2-methoxy-3-(3-methyl-2-butenyl)-4-oxo-4 H-pyrido [1,2-a] pyrimidine (IV), 3-methoxy-3-(3-methyl-2-butenyl)-2-oxo-2H-pyrido[1,2-a]pyrimidine (V), 2-methoxy-3-(2,3-dihydroxy-3-methyl-1-butyl)-4-oxo-4H-pyrido[1,2-a] pyrimidine (VI), and 4-methoxy-3-(2,3-dihydroxy-3-methyl-1-butyl)-2-oxo-2H-pyrido[1,2-a] pyrimidine (VII). Animal experiments revealed that compound (IV) has anticonvulsant activity, compounds (V) and (VI) have far lower activity than compound (IV).