Abstract: The novel polymers of the present invention are prepared by reacting a heterocyclic nitrogen compound containing at least one --N(H)-- group in the ring, an aldehyde and amino-substituted polymer (e.g., an ethylene alpha-olefin interpolymer substituted by primary amino or secondary amino groups) to form an oil soluble Mannich base derivative useful as antioxidant additive in oleaginous compositions such as lubricating oils and fuels. Preferred heterocyclic nitrogen compound are azoles such as benzotriazoles and alkyl-substituted benzotriazoles. Preferred amino-substituted interpolymers comprise amino-substituted ethylene propylene norbornene terpolymers. The polymers of this invention are oil soluble and are useful as dispersants, viscosity index improver dispersants, and as antiwear and antioxidant additives in oleaginous compositions.