1,9-Disubstituted phenalenes-I. Synthesis of n- and s-derivatives of 9-hydroxy-1-phenalenone

Article abstract of DOI:10.1016/0040-4020(78)89016-4

The reaction of 9-hydroxy-1-phenalenone with Ag₂O and alkyliodides gives the analogous β-keto-ethers from which synthetic pathways have been devised to isolate and characterise some nitrogen and sulphur derivatives. As intermediates stable phenalenium cations can be isolated by the reaction of 9-substituted 1-phenalenones with [(C₂H₅)₃O]+BF₄-. Whenever possible, a strong intramolecular H-bond is formed between the 1-and 9-substituents as shown by the low-field resonances of the respective hydrogens in the ¹H NMR and the stability of the compounds towards reduction.