The present invention relates to compounds of formula (I), and salts thereof and the pharmaceutical composition containing them in treatment of various diseases, as allergic rhinitis where R1 and R2 are, independently, hydrogen, halogen, C1_3 alkyl or C1-3alkoxy; R3 is phenyl optionally substituted by R4 and R5 which are, independently hydrogen, halogen, C1-3 alkyl, C1-3-alkoxy, fluoro-, difluoro- and trifluoromethyl, nitrile group, N,N-diC1-3alkyl-amide, carboC1-3 alkoxy or C1-3alkylsulphone groups; R3 is pyridyl group containing nitrogen at various positions in the benzene ring, n is one of the integers 1 or 2.