New N4-substituted piperazides and morpholide of pyrimidin-8-on [2,1-f]-theophylline-9-propanoic acids amides 4- 9 were synthesized and evaluated for their affinity at 5-HT1A and 5-HT2A receptor subtypes. Compound 6 containing benzyl substituted nitrogen (N4) was the most active one.