Facile isomerization of 2-(dicyanomethylene)-1,3-indandione to 2,3-dicyano-1,4-naphthoquinone

Abstract

There is considerable interest in highly conjugated, planar, electron-acceptor molecules that form stable anion radical salts with appropriate cationic species, as many of these salts are organic semiconductors or organic metals.1

Recent Heterocyclic Compounds from (1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile

“…It was reported earlier that 1 is isomerized to 2,3‐dicyano‐1,4‐naphthoquinone 3 when brought in contact with electron donors (Figure ). Additionally, the reaction of 1 with arylazoaminopyrazoles , 2‐mercaptobenzazoles , thiocarbohydrazides, and thiocarbazones as well as N ‐arylisoindolines has been reported.…”

“…The formation of 81a , 81b , 81c , 81d may be assumed to arise from a minor fraction of the amidine 79a , 79b , 79c , 79d that undergoes the Michael addition–elimination sequence giving 81a , 81b , 81c , 81d . On the other hand, the possibility exists that CNIND ( 1 ) in the presence of electron donors as 79a , 79b , 79c , 79d underwent an electron transfer rearrangement to the 2,3‐dicyano‐1,4‐naphthoquinone 3 . Consequently, the reaction between 1 and 79a was carried out under the same conditions as earlier.…”

Novel Reaction Products from Thiobarbituric Acid of Biological Interest

“…Continuation of our studies on the reactions of 2-dicyanomethyleneindane-1,3-dione (15) with compounds containing active methylene groups such as N-arylisoindolines [45], arylaminomethylbenzimidazole-2-thiols [46], thioxopyrimidine derivatives [40], benzimidazolylacetonitrile [47], and 2-mercaptobenzazoles [48] prompted us to investigate the behavior of 2-dicyanomethyleneindane-1,3-dione (15) and its facile isomer 2,3-dicyano-1,4-naphthoquinone [49,50] The 1 H-NMR spectrum of 19 displayed two broad singlets at 11.80 and 12.15 ppm due to pyrimidine-NH's, in addition to the aromatic protons. In its 13 C-NMR spectrum, C-6 and C-5 resonate at δ 166.44 and 105.00 respectively; further peaks at δ 143.20, 149.90 (Ar-C-OH), 167.34 (C = O) and 182.50 (C = S) were also observed.…”

Recyclisation of carbo- and heterocyclic compounds involving malononitrile and its derivatives

“…A scheme for the transformation of 2-dicyanomethyleneindane-1,3-dione 55 into salts 56 has been proposed. 59 The transformation is attained by refluxing 55 in acetonitrile in the presence of lithium iodide or methyltriphenylphosphonium iodide or by stirring it in dry THF with finely divided sodium. The reaction scheme includes a single-electron transfer in the indanedione 55 resulting in symmetrical radical anion 57, which cyclises to give spirocyclopropane intermediate 58.…”