| abstract |
The invention provides compounds of formula ( I ) and pharmaceutically acceptable salts thereof, wherein R1 is H, chlorine, or bromine; R2 is electron attractive groups selected from the group consisting of CF3, CN, fluorine, CH3SO3, CF3SO3, and NO2; R3 is linear or branched alkyl having 1 to 10 carbon atoms, linear or branched alkoxyalkyl having 2 to 10 carbon atoms, aliphatic alcohol having 1 to 10 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms. The invention also relates to methods for preparing the said compounds and the composition comprising the same. The compounds of the present invention have the effect of beta 2- receptor agonist and can be used for the treatment of asthma and bronchitis. <CHEM> |