A. V. Eremkin

Three-component synthesis of 2-chloropyridine-3,4-dicarbonitriles

According to published data, tetracyanoethylene reacts with ketones in the presence of a catalytic amount of hydrochloric acid to give 4-oxoalkane1,1,2,2-tetracarbonitriles [1, 2]. It is also known that concentrated hydrochloric acid reacts with 4-oxoalkane-1,1,2,2-tetracarbonitriles to produce 2-chloropyridine-3,4-dicarbonitriles [3]. These data suggest that 2-chloropyridine-3,4-dicarbonitriles could be prepared via one-pot procedure, i.e., without isolation of 4-oxoalkane-1,1,2,2-tetracarbonitriles, which should make their preparation simpler and less expensive.

Reaction of tetracyanoethylated cyclohexanones with water in acidic medium

It was reported earlier that 4-oxoalkane-1,1,2,2tetracarbonitriles depending on different factors react with hydrohalic acids to form 2-halopyridine-3,4dicarbonitriles [1–3], 2-halo-6-hydroxy-5,6-dihydroxypyridine-3,4,4(1Н)-tricarbonitriles [4], pyrrolo[3,4-c] pyrrole-1,3,4,6(2H,3аH,5H,6аH)-tetraones [1], 3-halo6-oxo-2,7-diazabicyclo[3.2.1]oct-3-ene-4,5-dicarbonitriles [5]. At the same time the influence of the structure of 4-oxoalkane-1,1,2,2-tetracarbonitriles on the reaction with aqueous sulfuric acid was not studied. Only reaction of 50% sulfuric acid with 3-methyl-4oxopentane-1,1,2,2-tetracarbonitrile to afford 5,6-dimethyl-2-oxo-1,2-dihydropyridine-3,4-dicarbonitrile in 10% yield has been reported [3].

Reaction of 4-aryl-2-aminobuta-1,3-diene-1,1,3-tricarbonitriles with CH-nucleophiles. I. Synthesis of 5-aryl-2,4-diamino-8,8-dimethyl-6-oxo-6,7,8,9-tetrahydro-5H-chromeno-[2,3-b]pyridine -3-carbonitriles

Abstract5-Aryl-2,4-diamino-8,8-dimethyl-6-oxo-6,7,8,9-tetrahydro-5H-chromeno[2,3-b]pyridine-3-carbonitriles were synthesized from 4-aryl-2-aminobuta-1,3-diene-1,1,3-tricarbonitriles and dimedone.

Regioselective reaction of 5,6-dialkyl-2-halopyridine-3,4-dicarbonitriles with ammonia

The reaction of 5,6-dialkyl-2-halopyridine-3,4-dicarbonitriles with alcoholic ammonia under elevated pressure gave 5,6-dialkyl-2-aminopyridine-3,4-dicarbonitriles as a result of nucleophilic replacement of the halogen atom by amino group. 6,7-Dialkyl-4-halo-1H-pyrrolo[3,4-c]pyridine-1,3(2H)-diimines were formed in analogous reaction at room temperature in the presence of potassium carbonate.

Synthesis of diethylammonium 3,4-dicyano-5,6,7,8-tetrahydroquinolin-2-olates

4-Oxoalkane-1,1,2,2-tetracarbonitriles are products of addition of tetracyanoethylene to ketones. Their molecules possess several electrophilic centers capable of reacting with nucleophiles. However, studies on reactions of these compounds with nitrogen-centered nucleophiles are very few in number. It was reported that reactions of 4-oxoalkane-1,1,2,2-tetracarbonitriles with aqueous ammonia lead to formation of isonicotinic acid derivatives [1] and 2,7-diazabicyclo[3.2.1]oct-3-enes [2].

Synthesis of 5-amino-3H-pyrrole-3,4-dicarbonitriles from 4-aryl-4-oxobutane-1,1,2,2-tetracarbonitriles

It is known that 4-oxoalkane-1,1,2,2-tetracarbonitriles react with nitrogen-centered nucleophiles, such as ammonia and amines, to give 3-amino-7-oxo-4,6-diazabicyclo[3.2.1]oct-2-ene-1,2-dicarbonitriles [1], 3-amidinio-2-aminopyridine-4-carboxylates [2], diethylammonium 3,4-dicyano-5,6,7,8-tetrahydroquinolin-2-olates [3], and ammonium 4-aryl-4-oxo-1,1,2-tricyanobut-2-en-1-ides [4]. However, these results do not allow us to draw a definite conclusion on the direction of attack by N-nucleophiles on the reaction centers in polyelectrophilic 4-oxoalkane-1,1,2,2-tetracarbonitriles.

Synthesis of a new organic anion by reaction of 4-aryl(hetaryl)-4-oxobutane-1,1,2,2-tetracarbonitriles with ammonia

4-Oxoalkane-1,1,2,2-tetracarbonitriles are known to react with concentrated aqueous ammonia to produce compounds of two types. Adducts of tetracyanoethylene and cyclic ketones (such as cyclopentanone and cyclohexanone) give rise to 2,7-diazabicyclic compounds [1], whereas from aliphatic tetracyanoethylated ketones isonicotinic acid derivatives are formed [2]. There are no published data on reactions of aqueous ammonia with tetracyanoalkanones derived from methyl aryl(hetaryl) ketones. When such reactions were carried out under the conditions reported in [1, 2], strong tarring occurred, and no individual products were isolated. By varying the conditions of this reaction we succeeded in obtaining ammonium 4-aryl1,1,2,2-tetracyano-4-oxobutan-1-ides IIa–IIc by mixing ketones Ia–Ic with a freshly prepared solution of ammonia in ethyl acetate at reduced temperature. Structures analogous to IIa–IIc but having singly charged metal cations were reported in [3, 4]. Compounds IIa–IIc turned out to be unstable in the solid state: on exposure to air they lost hydrogen cyanide with formation of ammonium 4-aryl-1,1,2-tricyano-4oxobut-2-en-1-ides IIIa–IIIc that are derivatives of a new organic anion. Intermediate formation of ammonium salts IIa–IIc is confirmed by their transformation into initial ketones Ia–Ic by the action of dilute hydrochloric acid immediately after isolation. Some structural similarity of salts IIIa–IIIc to betaines described in [5] may be noted. The latter were synthesized from tetracyanoethylene and pyridinium ylides. The structure of compounds IIIa–IIIc was confirmed by their IR, H NMR, and mass spectra and elemental analyses. The synthesis of salts III is an example of new reaction pathway of 4-oxoalkane1,1,2,2-tetracarbonitriles with ammonia. Ammonium 1,1,2-tricyano-4-(4-methoxyphenyl)4-oxobut-2-en-1-ide (IIIa). 4-(4-Methoxyphenyl)-4oxobutane-1,1,2,2-tetracarbonitrile (Ia), 0.139 g (0.5 mmol), was added to 2 ml of a freshly prepared solution of ammonia in ethyl acetate, cooled to –10°C, and the mixture was vigorously stirred until it became homogeneous. After several minutes, a solid separated and was filtered off, washed with cold ethyl acetate, and kept for 5–7 days on exposure to air. Yield 0.115 g (86%), mp 84–85°C. IR spectrum, ν, cm: 2230, 2199 (C≡N); 1667 (C=O). H NMR spectrum, δ, ppm: 3.81 s (3H, OCH3), 6.51 s (1H, CH), 7.01 d (2H, Harom), 7.07 br.s (4H, NH4), 7.79 d (2H, Harom). Mass spectrum: m/z 251 (Irel 49%) [M – NH3]. Found, %: C 62.51; H 4.77; N 20.95. C14H12N4O2. Calculated, %: C 62.68; H 4.51; N 20.88. Compounds IIIb and IIIc were synthesized in a similar way. Ammonium 1,1,2-tricyano-4-oxo-4-(2-thienyl)but-2-en-1-ide (IIIb). Yield 0.096 g (79%), mp 85– 87°C. IR spectrum, ν, cm: 2221, 2196 (C≡N); 1672 (C=O). H NMR spectrum, δ, ppm: 6.41 s (1H, CH), 7.16 d.d (1H, Harom), 7.19 br.s (4H, NH4), 7.65 d.d (1H, R = 4-MeOC6H4 (a), 2-thienyl (b), 3,4-(MeO)2C6H3 (c). ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 4, pp. 597–598.

Reaction of tetracyanoethylene with aldehydes. Synthesis of 6-imino-2,7-dioxabicyclo[3.2.1]octane-4,4,5-tricarbonitriles

It was discovered by means of dynamic NMR that the 1-(cis-1-methylprop-1-en-1-yl)-1,2-dimethyl-acenaphthylenonium ion generated under conditions of “long life” for carbocations underwent fast (ΔG#35.8 kJ mol−1 at −103°C) degenerate 1,2-shift of the cis-dimethylvinyl group. Quantum-chemical calculations by DFT method predict lower rate of 1,2-shift for the trans-dimethylvinyl group compared to cis-dimethylvinyl group and dependence on the cations conformation of the rates of these processes and of the rearrangement mechanism into the ions of phenalenyl type.

Three-component “domino” synthesis of 1,8-dialkyl-3-halo-8-methyl-6-oxo-2,7-diazabicyclo[3.2.1]oct-3-ene-4,5-dicarbonitriles

We previously reported on reactions of tetracyanoalkanones with hydrohalic acids, which could lead to formation of two types of compounds, depending on the substrate structure: α-unbranched ketones give rise to alkyl-substituted 2-halopyridine-3,4-dicarbonitriles [6], whereas alkyl-substituted 2-halo-6-hydroxy1,4,5,6-tetrahydropyridine-3,4,4-tricarbonitriles were obtained from ketones branched at the α-position [7].

Three-component synthesis of 2-(4-amino-2,5-dihydro-1H-imidazol-5-ylidene)malononitriles

Abstract2-(4-Amino-2,5-dihydro-1H-imidazol-4-ylidene)malononitriles were synthesized by three-component reaction of tetracyanoethylene, carbonyl compound, and ammonium acetate. The synthesis can be performed in two steps with intermediate isolation of 2-aminoethene-1,1,2-tricarbonitrile, as well as using preliminarily prepard 2-aminoethene-1,1,2-tricarbonitrile and 1,3,5-trisubstituted 2,4-diazapentadienes.