Catalyst-Free Phosphorylation of Acridine with Secondary Phosphine Chalcogenides: Nucleophilic Addition vs S_N^HAr Reaction

Abstract

Acridine adds secondary phosphine chalcogenides HP(X)R 2 (X = O, S, Se; R = Ar, ArAlk) under catalystfree conditions at 70−75 °C (both in the presence and absence of the electron-deficient acetylenes) to give 9chalcogenophosphoryl-9,10-dihydroacridines in 61−94% yields. This contrasts with pyridines, which under similar conditions undergo an S N H Ar reaction, wherein electron-deficient acetylenes play the role of oxidants. For acridine, the S N H Ar step has been accomplished by the oxidation of the intermediate 9phosphoryl-9,10-dihydroacridines (X = O) with chloranil.

Recent Advances in the Construction of Phosphorus‐Substituted Heterocycles, 2009–2019

“…Howerer, only a few phosphorylated acridines are the focus of chemists, possibly due to the lack of conventional methods for their synthesis. To cross this gap, the Trofimov group described a facile nucleophilic phosphorylation of acridines with secondary phosphine chalcogenides, which provided an efficient method to generate 9‐chalcogenophosphoryl‐9,10‐dihydroacridines 205 . This reaction proceded without any catalyst, external oxidants and with or without solvent to give the products 205 in good to excellent yields (Scheme ).…”

Electrochemical Aromatization of Dihydroazines: Effect of Chalco­genophosphoryl (CGP) Substituents on Anodic Oxidation of 9-CGP-9,10-dihydroacridine

“…It should be noted that the chemical oxidation of dihydroacridines 2 occurs similarly, giving close yields of P-substitution products 3. 17 To explain the revealed features of the electrochemical (as well as chemical) behavior of P-substituted dihydroacridine intermediates, their physicochemical properties were studied in detail using the methods of X-ray diffraction analysis, cyclic voltammetry, and also quantum-chemical calculations.…”

“…Compounds 2e-i were prepared by the reported methods. 17 Compounds 2a-d were prepared in the same way. Acridine (1; 2.0 mmol) and the appropriate phosphonate (2.1 mmol) were stirred without solvent under an argon atmosphere at 75-80 °C for 1-10 h (see also Scheme 2).…”

“…16 It is also important to note that the addition of a nucleophile is not a guarantee of a successful aromatization stage. For example, it was previously shown that acridine easily interacts with CGPs to form stable dihydroacridine intermediates; 17 however, attempts at their oxidative aromatization under the action of chloranil have been only partially successful.…”

A HClO4‐Catalyzed Substitutive Phosphorylation of Anthracene‐9‐ols with P(O)−H Compounds to Phosphorylated 9,10‐Dihydroanthracenes

“…[1e] Accordingly, developing elegant protocols for the construction of these molecules remains an ever-increasing point of interest for synthetic chemists. [2][3][4][5] On the other hand, as a special class of organophosphorus compounds, phosphorus-substituted heterocycles have attracted considerable attention because of the importance and great synthetic value in many areas of science including biologically pharmaceuticals, agrochemicals, materials and ligands. [6] Thus, it is suspected that phosphorylated 9,10dihydroanthracenes, which integrate both the 9,10-dihydroanthracene skeleton and phosphoryl group at a tri-or tetrasubstituted carbon center, potentially have some unique properties.…”