Synthesis of 2-aryl-3-nitro-4H-1-benzopyran-4-ones

Article abstract of DOI:10.1055/s-1992-26198

2-Aryl-3-nitro-4H-1-benzopyran-4-ones (or 3-nitroflavones) 3 are conveniently prepared in good yields using a two-step approach starting from 2-aryl-3-chloro-3,4-dihydro-4-hydroxy-3-nitro-2H-1-benzopyrans 1. A general synthesis of the novel 2-aryl-3-chlor