Search

The crystal structures of new salt forms of the known nitrogen-containing pharmaceuticals (dacarbazine, metoclopramide, and acetylcholine) in which 1,1,2,3,3-pentacyanopropenide anion acts as a counterion are analyzed by X-ray diffraction. It is found that in the crystals of studied salts with dacarbazine (in the form of a monohydrate) and metoclopramide, the mentioned anion plays the role of a structure-forming spacer, linking with more than one cation by classical hydrogen bonds. The types of cation and anion localization in the studied salts are revealed. They are: layered in the crystals with dacarbazine, stacked with the cation and anion alternation in the crystals with metoclopramide, and anion columns surrounded by cations in the crystals with acetylcholine. The tendency of the pentacyanopropenide anion to disordering in the crystals of metoclopramide and acetylcholine salts is detected.

Aseries of cyclobutane-1,1,2,2-tetracarbonitriles contained a compound with significant activity against various cancer cell lines. The compound featured a thiosemicarbazide and the α,β-unsaturated aldehyde myrtenal in its structure and showed the highest activity against leukemia cells, the average growth inhibition against which was 88%. The proposed mechanism of action was associated with alkylation of the nucleophilic regions of tumor-cell DNA. The results showed that compounds with an ethyl-1,1,2,2-tetracarbonitrile fragment inhibited proliferation of malignant cells.

We discovered a new method to methylate tertiary amines such as urotropine, triethylamine, pyridine, 2-methylpyridine, 4-acetylpyridine, and isonicotinamide, up to quaternary ammonium compounds, with 1,1-dicyano-2-methoxy-2-oxoethane-1-ide being the counterion. Methyl-1,3,5,7-tetraazaadamantan-1-ium 1,1-dicyano-2-methoxy-2-oxoethane-1-ide, N,N-diethyl-N-methylethanaminium 1,1-dicyano-2-methoxy-2-oxoethane-1-ide, and substituted-methylpyridinium 1,1-dicyano-2-methoxy-2-oxoethane-1-ides were synthesized. Quaternary ammonium compounds of 1,1-dicyano-2-methoxy-2-oxothane-1-ide were synthesized within a single stage by stirring methanol solutions of tertiary amines with ethene-1,1,2,2-tetracarbonitrile (ETCN) at room temperature. In the reaction of ETCN with tertiary amines in methanol, processes occur that form the 1,1-dicyano-2-methoxy-2-oxoethane-1-ide fragment with simultaneous N-methylation. Crystal structures based on X-ray diffraction analysis of the obtained compounds were studied.

Base-catalyzed nucleophilic addition of carbon nucleophiles to the exocyclic double bond of 2-(5-aryl-4-methyl-2-oxo-1,2-dihydro-3H-pyrrol-3-ylidene)malononitriles afforded spiro-fused pyrrole derivatives, 7-amino-3-aryl-4-methyl-1-oxo-8-oxa-2-azaspiro[4.5]deca-3,6,9-triene-6-carbonitriles. The products can be regarded as rare structural analogs of biologically active spirans based on isatin.

A library of 29 2-amino-6-sulfanylpyridine-3,5-dicarbonitriles functionalized with a pyridoxine moiety was synthesized using a three-component one-pot reaction of aldehyde derivative of pyridoxine,...

1-[2-(1H-indol-3-yl)ethyl]-4-acetyl-3-hydroxy-5-phenyl-1H-pyrrole-2(5H)-ones were synthesized by the short heating of a mixture of tryptamine, aromatic aldehyde, and methyl acetylpyruvate followed by stirring at room temperature for one day.

A procedure has been developed for the synthesis of methyl 6-alkyl-3-cyano-2-halopyridine-4-carboxylate by three-component reaction of 4-oxoalkane-1,1,2,2-tetracarbonitriles with hydrogen halides in methanol.

A simple method for the synthesis of inaccessible gem-dinitro derivatives of pyridine is described. A wide range of 2-halogencycloalka[b]pyridine-3,4-dicarbonitriles are produced by the three-component reaction (ketone, TCNE, hydrohalic acid), side-chain nitration of latter with 60% nitric acid in a solvent-free conditions leads to the formation of gem-dinitro derivatives with high selectivity and without disturbing of other reaction centers.

4-Aryl-2-aminobuta-1,3-diene-1,1,3-tricarbonitriles (benzylidene derivatives of malononitrile dimer) reacted with bromo(cyano)acetic acid amide and esters to give the corresponding 2-amino-6-aryl-5-cyano-4-(dicyanomethylidene)-3-azabicyclo[3.1.0]hex-2-ene-1-carboxylic acid amides and esters.

Reactions of 2-(2-aminoethoxy)ethanol with mixtures of an aromatic aldehyde and aroylpyruvic acid methyl ester have afforded 5-aryl-4-aroyl-3-hydroxy-1-[2-(2-hydroxyethoxy)ethyl]-3-pyrrolin-2-ones. Antihypoxic activity of the synthesized compounds has been studied.

Reactions of 3-amino-8-hydroxy-1,6-dioxo-2,7-diazaspiro[4.4]non-3-ene-4-carbonitriles with aqueous hydrohalic acid led to the formation of alkyl-substituted pyrrolo[3,4-c]-pyrrole-1,3,4,6-tetraones.

The reaction of sodium 2-acyl(aroyl)-1,1,3,3-tetracyanopropenides with hydroiodic acid at heating led to the formation of 1-alkyl(aryl)-4-amino-6-iodo-3-oxo-1,3-dihydrofuro[3,4-c]pyridine-7-carbonitriles.

2′-Oxo-1′,2′-dihydrospiro[cyclopropane-1,3′-indole]-2,2,3,3-tetracarbonitriles reacted with oxygencentered nucleophiles to form addition products at the cyano groups with conservation of the three-membered ring. Reactions of the title compounds with alcohols required the presence of base catalyst, and the products, 2-amino-4,4-dialkoxy-2′-oxo-1′,2′-dihydrospiro[3-azabicyclo[3.1.0]hex-2-ene-6,3′-indole]-1,5-dicarbonitriles, were converted into the corresponding 2-imino-2′,4-dioxospiro[3-azabicyclo[3.1.0]hexane-6,3′-indole]-1,5-dicarbonitriles and 2,2′,4-trioxospiro[3-azabicyclo[3.1.0]hexane-6,3′-indole]-1,5-dicarbonitriles by the action of acetic and sulfuric acids, respectively. The reactions with ketone oximes occurred in the absence of a catalyst, yielding 2-amino-4,4-bis(alkylideneaminooxy)-2′-oxo-1′,2′-dihydrospiro[3-azabicyclo[3.1.0]hex-2-ene-6,3′-indole]-1,5-dicarbonitriles. The reactions with thiols, aliphatic amines, and anilines were accompanied by opening of the three-membered ring. In the reactions with triphenylphosphine and thiols 2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)malononitrile was obtained, while morpholine and N,N-dimethylaniline gave rise, respectively, to 3,3-diaryl-and 3,3-dimorpholino-1H-indol-2(3H)-ones and tri- and dicyanoethylene derivatives.

We now propose a new synthetic approach to photochromic diarylethenes, which is based on the reaction of tetracyanoethylene with ketones as key intermediate step. Tetracyanoethylation of ketones has been well documented; however, there are almost no published data on reactions of aryl arylmethyl ketones with tetracyanoethylene. Adducts of tetracyanoethylene with ketones of the general formula R(CO)CH2R′ were used as starting compounds to obtain heterocycles containing an RC=CR′ fragment [4–10]. Analogous reactions with aryl arylmethyl ketones Ar(CO)CH2Ar could give rise to various 1,2-diarylethenes as new potential photochromes. We were the first to react tetracyanoethylene with 1,2-diarylethanones Ia and Ib in the presence of a catalytic amount of hydrochloric acid. As a result, we isolated 3,4-diaryl-4-oxobutane-1,1,2,2-tetracarbonitriles IIa and IIb. The substrates were deoxybenzoin (Ia), the parent compound of the 1,2-diarylethanone series, and 1,2-bis(2,5-dimethylthiophen-3-yl)ethanone (Ib). The latter was selected taking into account that diarylethenes containing thienyl substituents are most promising from the viewpoint of the design of practically useful photochromic devices [1]. Ketone Ib was synthesized in a number of steps starting from hexane2,5-dione [11].

In reaction of alkyl 2-amino-5,6-dialkyl-3-cyanopyridine-4-carboxylates with isocyanates formed unstable ureas, and with nitrous acid at 60–70°C alkyl 5,6-dialkyl-2-oxo-1,2-dihydro-4-pyidinecarboxylates were obtained. It was shown for the latter that their reactions with organic acids and amides occurred at the cyano group, and the alkaline hydrolysis involved the ester group.

A simple method for the synthesis of inaccessible gem-dinitro derivatives of pyridine is described. A wide range of 2-halogencycloalka[b]pyridine-3,4-dicarbonitriles are produced by the three-component reaction (ketone, TCNE, hydrohalic acid), side-chain nitration of latter with 60% nitric acid in a solvent-free conditions leads to the formation of gem-dinitro derivatives with high selectivity and without disturbing of other reaction centers.

An unusual direction has been found for the interaction of alkyl 5,6-dialkyl-2-amino-3-cyanopyridine-4-carboxylates with primary amines leading to the formation of 2,6,7-trialkyl-4-amino-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-1,3-diones.

An unusual route has been found for the hydrolysis of 3-amino-1,1-dialkoxy-6,7-dialkyl-4-aryl-3a,4,5,7a-tetrahydro-1H-pyrrolo[3,4-c]pyridine-3a,7a-dicarbonitriles in acidic medium which leads to the formation of alkyl 5,6-dialkyl-2-amino-3-cyanopyridine-4-carboxylates.

The scission of the urea group in 5-alkyl-2-amino-3,4-dicyano-N-ureidopyrroles on boiling in KOH solution in DMSO was observed to give 5-alkyl-1,2-diamino-3,4-dicyanopyrroles which were used for the synthesis of pyrrolo[1,2-b][1,2,4]triazepines by reaction with acetylacetone.

6,6-Dimethyl-4,8-dioxospiro[2.5]octane-1,1,2,2-tetracarbonitrile (III), synthesized by the interaction of tetracyanoethylene with 2-bromo-5,5-dimethyl-1,3-cyclohexanedione, reacts with alcohols and ketoximes to form 2-alkoxy-2-(3-alkoxycarbonyl-2,2-dimethylpropyl)-5-amino-3-dicyanomethylene-4-cyano-2,3-dihydrofurans and 2-alkylidenaminoxy-2-(3-alkylidenaminoxycarbonyl-2,2-dimethylpropyl)-5-amino-3-dicyanomethylene-4-cyano-2,3-dihydrofurans. Compound III with triarylphosphines forms 2-(triarylphosphoranilidenamino)-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3,4,4-tricarbonitriles.

A second direction has been found in the thermal conversions of 2,5-diaryl-3,3,4,4-tetracyanopyrrolidines. When they are refluxed in DMF or DMSO in the presence of a base, rearrangement does not take place, but rather elimination of two molecules of hydrogen cyanide and the formation of 2,5-diaryl-3,4-dicyanopyrroles. It was shown that 2,6-diphenyl-4,5-dicyanopyrrolo[2,3-d]pyrimidine is formed when the basicity of the medium is within certain limits.

The addition of hydrogen iodide occurs regioselectively to the cyano groups of the dicyanomethylene fragment of tetracyanopropenides (I).

5-Alkyl-2-amino-3, 4-dicarbamoyl-4-cyano-4, 5-dihydrofurans were synthesized by the reaction of 1,1, 2tricarbamoyl-2-cyanoethane with carbonyl compounds in the presence of catalytic amounts of triethylamine in an aqueous medium. The structure of the dihydrofuran (Vb) was proved by x-ray crystallographic investigation of a single crystal.

Reactions of a tetracyanobicycloalkene (1) with methanol and ethylene glycol give derivatives of 2-aminopyrrolin-5-one (2 and 3), and acid hydrolysis of3 gives an imide (4). According to an X-ray structural investigation, acis orientation of the heterocycle (with respect to the C=C bond) is realized in2; in the case of4, thecis/trans ratio of the isomers in the crystal and solution is 2∶1.

Reactions of a tetracyanobicycloalkene (1) with methanol and ethylene glycol give derivatives of 2-aminopyrrolin-5-one (2 and 3), and acid hydrolysis of3 gives an imide (4). According to an X-ray structural investigation, acis orientation of the heterocycle (with respect to the C=C bond) is realized in2; in the case of4, thecis/trans ratio of the isomers in the crystal and solution is 2∶1.

Methanol molecules add to the cyano groups of hexacyanocyclopropane 1 in the presence of sodium methylate to give 1,4-adduct 2. The interaction of 1 with N-methylpyridinium iodide leads to opening of the cyclopropane ring and to the formation of propenide 3 and iodine cyanide 4; the structure of 2 was established by an X-ray crystallographic study.

A second direction has been found in the thermal conversions of 2,5-diaryl-3,3,4,4-tetracyanopyrrolidines. When they are refluxed in DMF or DMSO in the presence of a base, rearrangement does not take place, but rather elimination of two molecules of hydrogen cyanide and the formation of 2,5-diaryl-3,4-dicyanopyrroles. It was shown that 2,6-diphenyl-4,5-dicyanopyrrolo[2,3-d]pyrimidine is formed when the basicity of the medium is within certain limits.

The first study on reactions between tetracyanoethylene and carbonyl compounds was published in 1957 [1]. We extended the investigations in this field and established that the arising b,b,g,g-tetracyanoalkanones were very reactive [2, 3]. However in this process were involved only some b-dicarbonyl compounds whose addition to tetracyanoethylene followed by cyclization due to interactions NH^CN and OH^CN resulted in formation of pyrroles, furans, and pyrans [4].

An unusual route has been found for the hydrolysis of 3-amino-1,1-dialkoxy-6,7-dialkyl-4-aryl-3a,4,5,7a-tetrahydro-1H-pyrrolo[3,4-c]pyridine-3a,7a-dicarbonitriles in acidic medium which leads to the formation of alkyl 5,6-dialkyl-2-amino-3-cyanopyridine-4-carboxylates.

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].

2,5-Substituted 3,3,4,4-tetracyanopyrrolidines react with primary alcohols in the presence of an excess of a base or with the base itself. 2-(N-Arylideneamino)-5-alkoxy-3,4-dicyanopyrroles are formed as a result of the reactions with alcohols, and 2,5-diamino-1-R-3,4-dicyanopyrroles are formed as the result of the reaction with primary aliphatic amines.

The reactions of 6,6-dialkyl-5,7-dioxo-4,8-dioxaspiro[2.5]octane-1,1,2,2-tetracarbonitriles with primary aliphatic alcohols lead to the formation of alkyl 2,2,3,3-tetracyanocyclopropanecarboxylates; the reactions of the same compounds with ketone oximes give 2-amino-4,4-bis(alkylideneaminooxy)-6-(alkylidene-aminooxycarbonyl)-3-azabicyclo[3.1.0]hex-2-ene-1,5-dicarbonitriles, while with aldehyde oximes 2-amino-2-oxo-1,5-dicyano-3-azabicyclo[3.1.0]hex-2-ene-6-carboxylic acid is formed.

Reduction of alkyl-2-amino-5,6-dialkyl-3-cyanopyridine-4-carboxylates with sodium borohydride in protic solvents gave rise to 4-amino-3-imino-6,7-dialkyl-1,3-dihydrofuro[3,4-c]pyridines that at hydrolysis in acid medium afforded the corresponding lactones.

The reaction of alkyl 5,6-dialkyl-2-amino-3-cyano-4-pyridinecarboxylates with certain O-nucleophiles was investigated, as a result of which 6,7-dialkyl-4-amino-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-1,3-diones were synthesized.

Tetracyanocyclopropyl ketones obtainable via modified Wideqvist reaction are accessible and convenient precursors of a number of heterocyclic systems [1–3]. Reactions of cyclopropyl ketones Ia–Ic with alkoxides give rise to 2-[2-alkoxy-5-amino-4-cyano-2-phenylfuran-3(2H)-ylidene]malononitriles [3]. We anticipated that replacement of the ketone acetal fragment in the latter by more labile semiacetal moiety should facilitate recyclization of the furan ring into pyrrole. Such transformation could be promoted using hydroxide ion instead of alkoxide in reactions with cyclopropyl ketones Ia–Ic. The above assumption was verified by studying the reaction of cyclopropyl ketones Ia–Ic with aqueous sodium hydroxide. We found that this reaction involves not only expected recyclization of furan ring into pyrrole but also annelation of pyridine ring. The structure of compounds IIa–IIc isolated by neutralization of the reaction mixture with a solution of sulfuric acid was confirmed by the H NMR and mass spectra. The H NMR spectra contained singlets at δ 7.12– 7.69 and 8.78–9.02 ppm, which were assigned to the hydroxy and NH protons, respectively, in the pyrrole ring. The NH proton in the pyridine ring resonated as

1,1,2,2-Tetracyanocyclobutanes are most frequently synthesized by a [2+2]-cycloaddition reaction [134]. The most facile reaction occurs between tetracyanoethylene and alkenes whose double bond is activated by electron-donor substituents. 1,1,2,2-tetracyanocyclobutanes are considered to be formed by a nonconcerted cycloaddition reaction involving a zwitterionic intermediate. The reactions of tetracyanoethylene with styrene [5] and vinyl ether [6] are assigned to this type of reactions. It is shown that first a charge-transfer complex is formed. Further, say, in the reaction of tetracyanoethylene with styrene, the

Single-stage synthesis of 3,7-diacyl-2,6-diamino-9,11-dioxo-10-aza[3,3,3]propella-2,6-dienes from 1,1,2-tricarbamoyl-2-cyanoethane and alkyl vinyl ketones, is reported.

Methanol molecules add to the cyano groups of hexacyanocyclopropane 1 in the presence of sodium methylate to give 1,4-adduct 2. The interaction of 1 with N-methylpyridinium iodide leads to opening of the cyclopropane ring and to the formation of propenide 3 and iodine cyanide 4; the structure of 2 was established by an X-ray crystallographic study.

It was observed that substituted bis(3-cyano-2-pyrrolyl) disulfides Ila-d are formed when hydrogen sulfide is passed through solutions of β,β-dicyano ketones Ia-d in organic solvents in the presence of catalytic amounts of triethylamine.

A new reaction was found for the preparation of difficult-to-obtain polyfunctional dihydrofurans, viz., the reaction of tetracyanoethylated ketones with hydrogen peroxide in the presence of a base.

Starting with the tetracyanoethane (I) and the crotonaldehyde hydrazone (II), the title compound (V) is synthesized as shown in the reaction scheme.

A new reaction was found for the preparation of difficult-to-obtain polyfunctional dihydrofurans, viz., the reaction of tetracyanoethylated ketones with hydrogen peroxide in the presence of a base.