By the action of 2-aminothiazole, 2-aminopyridines, and 2-aminopyrimid
ines, respectively, on 4-chloro-3-nitrocoumarin (3) the corresponding
4-heteroarylamino-3-nitrocoumarins 5-7 have been isolated in very good
yields. Reactions of coumarins 6 and 7 with either aqueous tetrabutyl
ammonium bisulfate/sodium hydroxide in a two phase system or 5% aqueou
s sodium hydroxide have been studied.