peri-Naphthylenediamines 22. Synthesis of 1,4,5-tris(dimethylamino)naphthalene and other "proton sponge" 4-amino derivatives

Article abstract of DOI:10.1007/BF02505681

Catalytic hydrogenation of 4-nitro-1,8-bis(dimethylamino)naphthalene afforded the previously unknown 1-amino-4,5-bis(dimethylamino)naphthalene, subsequent methylation of which gave 1-methylamino and 1-dimethylamino "proton sponge" derivatives. The pK_a values of 1-amino-, 1-methylamino-, and 1-dimethylamino-4,5-bis(dimethylamino)-naphthalenes estimated by ¹H NMR in DMSO-d₆ are equal to 9.8, 10.1, and 8.0, respectively.