Efficient and green synthesis of 2,2'(arylmethylene)bis-4-pyrones in an ionic liquid [bmim+][BF4-].

A series of sixteen 2,2'(arylmethylene)bis(3-hydroxy-6-methyl-4H-pyran-4-ones) have been prepared in high yield via an ammonium acetate-catalysed three-component reaction of an aromatic aldehyde (1 equiv.) and allomaltol (2 equiv.) in an ionic liquid [bmim⁺][BF₄^-]. The reaction work-up is simple and the ionic liquid can be easily separated from the product and reused. [ABSTRACT FROM AUTHOR]