1-(Substituted-aminoalkoxyphenyl)-2-methylene-1-alkanones, a class of compounds possessing antiallergic propertiesfor use in the treatment of allergic conditions, such as asthma prepared by etherifying an alkanoylphenol with an aminoalkyl halide, converting the ether formed to a salt of Mannich base by reacting it with a salt of a secondary amine in the presence of formaldehyde or paraformaldehyde and treating the Mannich salt with a weak base todeaminate the same and form the final product.