Reaction of 3-hydroxyquinoline-2,4-diones with inorganic thiocyanates in the presence of ammonium or alkylammonium ions: The unexpected replacement of a hydroxy group by an amino group

Abstract

3-Hydroxyquinoline-2,4-diones react with KSCN in the presence of the NH4+ ions to generate 2,3-dihydro-3-thioxoimidazo[1,5-c]quinazolin-5(6H)-ones, 2,3-dihydro-2-thioxo-1H-imidazo[4,5-c]quinolin-4(5H)-ones, and products of molecular rearrangement of the 3-aminoquinolinedione intermediates. Starting compounds with a benzyl (Bn) group at C(3) afford 3-aminoquinolinediones, even when only AcONH4 is used. The results of the reaction between 3-hydroxyquinoline-2,4-diones and KSCN in the presence of BuNH2 show that replacing a OH group with a secondary NH2 group is also possible. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.