Abstract A series of 1-(substituted benzyl)-3, 4, 5, 6-tetrahydro-2 (1H)-pyrimidonea was synthesized primarily by catalytic hydrogenation of the corresponding 1-(substituted benzyl)- 2 (1H)-pyrimidone. The pharmacological evaluation of these compounds in mice revealed a unique profile that included evidence of CNS stimulation and depression within the series and in the same compounds. Some members of this series induced signs of only CNS ...