The nucleoside derivatives possessing sedative and hypnotic effects.

N3-Substituted oxopyrimidines and their related compounds were synthesized. The central nervous system (CNS) depressant activities of the compounds such as hypnotic activity and barbiturate-induced narcosis have been evaluated. N3-Benzyl, o,m,p-xylyl, alpha-phenylethyl, phenacyl substituted and related oxopyrimidine nucleosides exhibited potent hypnotic activity by intracerebroventricular (i.c.v.) administration to mice. The results indicate that hypnotic action of oxopyrimidine nucleoside derivatives might relate to functional group at the N3 position on oxopyrimidine ring and stereospecificity of sugar moiety.