title: Structure-activity relationships in a series of 8-substituted xanthines as bronchodilator and A1-adenosine receptor antagonists.
abstract: Four new derivatives of 8-piperazine ethyl xanthine were synthesized and their bronchospasmolytic activity and A1-adenosine affinity were studied. Their relaxant action in the tracheal muscle was lower than that of theophylline and that of theophylline derivatives substituted at the 7-position. Only compound 9, where the methyl group in the 1-position of the theophylline was substituted by an isobutyl group, shows a good affinity towards the A1-adenosine receptor.
mesh_terms: D000818:Animals; D001993:Bronchodilator Agents / Q000737:chemistry / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D015394:Molecular Structure; D058915:Purinergic P1 Receptor Antagonists; D013329:Structure-Activity Relationship; D013806:Theophylline / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects; D014970:Xanthines / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001993:Bronchodilator Agents; D058915:Purinergic P1 Receptor Antagonists; D014970:Xanthines; D013806:Theophylline