Synthesis of the symmetrical methylene diesters from carboxylic ionic liquids

The reaction between carboxylic ionic liquids and dichloromethane, which provokes the formation of symmetrical methylene diesters, was carried out. The synthesis of these ionic liquid compounds was carried out in a microwave reactor, and the characterization by spectroscopic techniques of methylene diesters (methylene di-2-furoate, methylene di-2-picolinate, methylene dianthranilate, and methylene dioleate) is described and the crystal structures discussed. The crystal packing of methylene dianthranilate is characterized by trimer formation due to hydrogen bonding via interactions between the hydrogen atom of the primary amine group and the oxygen of the carboxylic group.