文摘
The first classical heterocyclic ionic liquid (IL) promoted C鈥揌 bond oxidant cross-coupling reaction for the intramolecular annulation of 5-(aryloxy)-1H-pyrazole-4-carbaldehydes to chromeno[2,3-c]pyrazol-4(1H)-ones has been disclosed. The promoter 1,3-dibutyl-1H-benzo[d][1,2,3]triazol-3-ium bromide can be easily recycled and reused with the same efficacies for at least five cycles in aqueous medium. The strategy works smoothly and provides an applicable protocol to construct a wide range of products.