Thiosemicarbazone and amidinohydrazone derivatives of some 1,4-naphthoquinones

Abstract

Syntheses of the 1-, 2-, and 4-thiosemicarbazones and the 1- and 4-amidinohydrazones of 2-hydroxy-1,4-naphthoquinone (I) are described. The position of condensation of the quinone (I) with thiosemicarbazide is pH dependent in contrast to condensation with aminoguanidine which is independent of pH. A possible explanation for this difference is presented. Chemical and spectral evidence is presented to support the structural assignments for the products.