The synthesis of 10-chloroethyl-2,3,4,10-tetrahydropyrimido[1,2-α] benzimidazole was described. The nucleophilic substitution of the chlorine atom by various amines was studied. As a result, 10-alkylaminoethyl-substituted derivatives of this tricycle containing alkylamines and 4-substituted piperazines were obtained. These compounds exhibited 5-HT ₂ antagonist activity; platelet antiaggregant properties; and moderate P2Y ₁ -antagonist, antiarrhythmic, and hypoglycemic action.