PHENAZINE SYNTHESES. II.¹ PHENAZINE ETHERS AND PHENAZINOLS

Abstract

The preparation of the simpler phenazines, as distinguished from the numerous more complex phenazines developed by the dye industry, has hitherto been hampered by cumbersome methods of synthesis and relatively poor yields. The general synthesis of Waterman and Vivian (1) has now, however, made more accessible a wide variety of phenazines (2), as well as a number of other nitrogen heterocycles. The nitro-group ring-closure of "Type A" (1), used in the synthesis of all the phenazine derivatives dealt with in this paper, is most simply represented3 by: i\r '' v +2 Fe 0 0 (220e-300°) (FeO from: Fe C204 • 2 H20-»~FeO + C02+C0 + 2H20)The present series of papers details the preparation of representative examples of these newly available compounds, so that with respect to the phenazine syntheses, the scope, flexibility, and limitations of the reaction may be more clearly delineated. SUMMARY 1. A number of new 2-nitrodiphenylamines and phenazines derived therefrom have been synthesized.

Phenazine Natural Products: Biosynthesis, Synthetic Analogues, and Biological Activity

“…Nucleophilic substitution of a 2-nitrophenyl halide with an aniline affords the corresponding 2-nitrodiphenylamine. The reaction conditions depend on the substitution pattern on the reagents and include normal base catalysis − or additional activation by copper metal, often referred to as Jourdan−Ullmann conditions (K 2 CO 3 , copper-bronze, neat or H 2 O) . Variations of Ullmann's reaction conditions have been reported by Denny and co-workers, who successfully applied anhydrous conditions implying CuCl/Cu, N- alkylmorpholine as a base, and high-boiling solvents such as butanediol. ,, This method was generally high-yielding except for very electron-deficient amines (8-aminoisoquinoline) 104 or sterically hindered anilines (e.g., 2-chloro-6-fluoroaniline) .…”

Preparation and Properties of Imido Intermediates (Imidogens)

“…A few limitations have been noted in these reactions. Thus, in the phenazine synthesis, an alkoxyl group is eliminated in preference to a hydrogen atom whenever both are in the appropriate position for reaction (319,321). Since an ethoxyl group meta to the position of cyclization is never eliminated this might indicate some form of complexing between the imido group and the 2'alkoxyl group, leading to the elimination.…”

“…Since an ethoxyl group meta to the position of cyclization is never eliminated this might indicate some form of complexing between the imido group and the 2'alkoxyl group, leading to the elimination. Advantage has been taken of this fact in the selective synthesis of 2-phenazinols (321). In some cases, 2'-chloro compounds give phenazines in which the chlorine atom has been lost (320).…”

Methanophenazin: Strukturaufklärung und Totalsynthese eines neuartigen Cofaktors aus methanogenen Archaea

“…6.1 Wege zu Phenazinen [60] Bei den meisten Synthesen von Phenazinderivaten ist der Aufbau des zentralen hetero- gen. Das in die angelsächsische Literatur auch als Vivian-Methode [63] eingegangene Verfahren wurde bereits viel früher von Nietzki und Ernst [64] zur Phenazin-Synthese durch Cyclisierung von 2-Aminodiphenylamin (30) eingesetzt. Die durch ipso-Substitution des reaktiven Vivian, Hartwell und Waterman [65] nutzten diese Methode zur Darstellung von 2-Chlorphenazin (33) Eine weitere, interessante Methode zur Synthese zahlreicher Phenazinderivate ist die Beirut-Reaktion. [66] Bei dieser Reaktion kondensiert man Benzofuroxan (36) 2) reduziert werden.…”

“…[66] Bei dieser Reaktion kondensiert man Benzofuroxan (36) 2) reduziert werden. [65] Ley und seine Mitarbeiter [67] nutzten Hydrochinon (41) zur Gewinnung von 42. Vorschrift von Kehrmann und Cherpillod [68] bzw.…”