REACTION OF 1-AMINO-2-PHENYLETHYNYL-9,10-ANTHRAQUINONE AND 2-ACYLETHYNYL-1-AMINO-9,10-ANTHRAQUINONE WITH HNO2 - SYNTHESIS OF 1H-3-ACYLNAPHTHO[2,3-G]INDAZOLE-6,11-DIONES

The reactions of 1-amino-2-phenylethynyl- and 2-acylethynyl-1-amino-9, 10-anthraquinones with HNO2 in a mixture of dioxane and a mineral acid at 20 degrees C were studied. Under these conditions, 2-alkynyl-1-ami no-9,10-anthraquinones, irrespective of the structure of the C=CR subs tituent, are cyclized into 3-substituted 1H-naphtho[2,3-g]indazole-6,1 1-diones. The nature of the acetylenic group in the initial compound a nd the choice of the mineral acid determine the structure of the subst ituent in position 3 of the product (1,1-dichloroalkyl or acyl) but ha ve no effect on the regiospecificity of cyclization.