Formation of cyclopropylazoarenes in the azo coupling reactions of the cyclopropanediazonium ion with active aromatic compounds

The decomposition of N-cyclopropyl-N-nitrosourea with K₂CO₃ generates a cyclopropyldiazonium intermediate, which is trapped in situ with 1- and 2-naphthols, 2,7-dihydroxynaphthalene or 8-hydroxyquinoline to afford azo coupling products.