Synthesis and Spectral Properties of N‐Aryl‐5‐hydroxy‐1,4‐naphthoquinone 4‐Imines.

Abstract

Quinones Quinones Q 0910Synthesis and Spectral Properties of N-Aryl-5-hydroxy-1,4-naphthoquinone 4-Imines. -A comparative study of oxidative amination of hydroxynaphthalenes (I), (IV), and (VII) with arylamines (II) and (V) by using three different oxidants is performed. The effect of electronic and steric factors in the arylamine on the yield and spectral properties of naphthoquinone imines (III), (VI), and (VIII) is examined. In the presence of K 3 Fe(CN) 6 , the yield of imines decreases from 85 to 3% in parallel with the basicity of arylamines. Generally, the reaction of hydroxynaphthalenes with arylamines in the presence of HIO 3 or NaIO 4 is characterized by higher yields of imines. The imine formation between tetrabromodihydroxynaphthalene (VII) and butoxyaniline (V) is accompanied by bromine replacement in position 2 through the arylamine residue yielding side product (IX). -(BUKHTOYAROVA, A. D.; EKTOVA, L. V.; ALEKSEEV, S. N.; BEREGOVAYA, I. V.; Russ.

Synthesis and in Vitro Antiproliferative Activity of New Phenylaminoisoquinolinequinones against Cancer Cell Lines

“…However, after the aqueous work-up of the mixture reaction, aminoquinone 4a was recovered and no reaction products were detected (TLC, 1 H-NMR). A plausible explanation for the lack of bromination of compound 4a could be attributed to the oxidation of the p -hydroxyphenylamino group of 4a with NBS [ 13 , 14 , 15 ] to give the corresponding electron-attracting iminoquinoyl group, which probably inhibits the bromination reaction at the quinone double bond and, under aqueous media, undergoes a reversible reduction to the hydroxyphenylamino group. In order to avoid the interference of the phenylamino substituent on the bromination reaction at the 6-position of 4a , we attempted to prepare the target brominated regioisomer 9 through a three step sequence, which involved the protection of the hydroxyl group in 4a , as the acetate, followed by bromination of 7a with NBS and further base-induced deprotection of acetyl group in 8 , of the hydroxyl group ( Scheme 2 ).…”

“…In the light of these facts we and other authors have reported the preparation and antiproliferative evaluation of 6,7-substituted aminoquinoline- and aminoisoquinolinequinones. Evidences arising from these studies demonstrate that insertion and change of location of alkylamino and halogen substituents in the quinone nucleus of the corresponding N -heterocyclic cores induce difference in the antiproliferative activity [ 13 , 14 , 15 ].…”