A series of desloratadine derivatives were stereoselectively synthesized and evaluated for H1 antihistamine activity. For the evaluation of H1 antihistamine activity, the in vitro histamine-induced contraction of the guinea-pig ileum assay (HC) was used. The synthesized desloratadine derivatives 7, 8 and 9 are structurally related to rupatadine and were generated by replacement of the 5-methyl-3-pyridine