[Hexahydroimidazo[1,5-a]-pyrazine. II. Synthesis of 7-phenyl-1,5,6,7,8,8a-hexahydroimidazo[,5-a]pyrazine-3(2H)-one and derivatives].

The synthesis and activity on the central nervous system of a series of 2-aryl or 2-alkyl-7-phenylhexahydroimidazo[1,5-a] pyrazin-3(2H)-ones (II a-f) are reported. The intermediate 3-carbomethoxy-1-phenylpiperazine (X) was prepared in six steps from aniline and methyl-2-chloroacrylate. Compared with that of derivatives of Zetidoline, the depressant activity of (II a-f) is markedly reduced.