Synthesis and CNS activity of tricyclic theophylline derivatives. 8-substituted imidazo[2,1-f]theophyllines

Based on previously described results of pharmacological in vitro and in vi vo tests of some series of pyrimido- and diazepino-[2,1-f]theophylline deri vatives, Ns-unsubstituted, N8-benzyl and N8-arylpiperazino-alkyl derivative s of imidazo[2,1-f]theophyllines were synthesized and tested for their CNS activity. It has been shown that tricyclic [2,1-f]theophyllines possess sed ative and analgesic activity. N8-Phenylpiperazinopropyl-1,3,6,7-tetrahydro- (8H)-imidazo[2,1-f]theophylline 6 showed significant anti-serotonin and lon g-lasting hypothermic effects. N8-Benzyl-1,3,6,8-tetrahydroimidazo-7-on[2,1 -f]theophylline 8 possess anticonvulsant properties. (C) 1999 Editions scie ntifiques et medicales Elsevier SAS.