Synthesis and calming activity of helicid derivatives containing the 3,4-dihydropyrimidin-2( H)-one and 3,4-dihydropyrimidine-2( H)-thione moiety.

A series of novel helicid derivatives containing 3,4-dihydropyrimidin-2(1 H)-one and 3,4-dihydropyrimidine2(1 H)-thione moiety ( 3a–3f and 4a–4f) were synthesized starting from helicid. The structure of the new compounds were characterized by ¹H NMR, IR and HR-MS spectra. The sedative-hypnotic activities of the target compounds were evaluated using the test of spontaneous locomotor activity in mice. All of the derivatives produced moderate to high activities; in particular, compound 4a presented the most potent sedative-hypnotic effect in comparison to the other derivatives, and derivatives 3a, 3c, 3d, 3e and 3f also showed potent activities. [ABSTRACT FROM AUTHOR]