A new type of cascade reaction: direct conversion of carbonyl compounds and malononitrile into substituted tetracyanocyclopropanes

A new type of chemical cascade reaction was found: the direct formation of cyclopropanes from carbonyl compounds and C-H acid. The action of free halogen or active halogen containing compounds on a mixture of 1 equiv of carbonyl compound and 2 equiv of malononitrile in a basic alcohol solution results in the formation of substituted 1,1,2,2-tetracyanocyclopropanes in 15-80% yield. The latter are well-known precursors for the different bicyclic heterosystems, among them compounds containing a cyclopropane ring and possessing different types of pharmacological activity. Thus, the new, simple and efficient ‘one-pot’ way to substituted tetracyanocyclopropanes in 50-80% yield was found directly from such simple and reasonable starting compounds as aldehydes, or some cyclic ketones, or substituted cyclohexanones and malononitrile.     

The first example of the cascade assembly of a spirocyclopropane structure: direct transformation of benzylidenemalononitriles and N,N′-dialkylbarbituric acids into substituted 2-aryl-4,6,8-trioxo-5,7-diazaspiro[2.5]octane-1,1-dicarbonitriles

The direct formation of substituted 2-aryl-4,6,8-trioxo-5,7-diazaspiro[2.5]octane-1,1-dicarbonitriles in 75-95% yields from benzylidenemalononitriles and N,N′-dialkylbarbituric acids is described.     

Electrocatalytic transformation of malononitrile and cycloalkylidenemalononitriles into spirobicyclic and spirotricyclic compounds containing 1,1,2,2-tetracyanocyclopropane fragment

Electrolysis of malononitrile and cycloalkylidenemalononitriles in EtOH in an undivided cell in the presence of NaBr affords spirobicyclic compounds containing a 1,1,2,2-tetracyanocyclopropane fragment in 50—88% yields.     

A new route to 2,3,5,6-tetrafluoroterephthal aldehyde and its chemical transformation

The title compound was prepared from commercial available and cheaper starting material terephthalolyl chloride by six-step reaction sequence in total 40% yield. Its chemical transformations were also studied.     

Electrocatalytic transformation of malononitrile and cycloalkylidenemalononitriles into spirotricyclic and spirotetracyclic compounds containing cyclopropane and pyrroline fragments

Electrolysis of cycloalkylidenemalononitriles and malononitrile in MeOH in an undivided cell in the presence of the NaBr—NaOMe mediator system gives spirotricyclic compounds containing cyclopropane and pyrroline fragments in 50—77% yields. Spirobicyclic and spirotricyclic tetracyanocyclopropanes undergo electrolysis in alcohols to afford spirotricyclic and spirotetracyclic products containing cyclopropane and pyrroline fragments in 50—93% yields.     

Electrocatalytic multicomponent cyclization of an aldehyde, malononitrile and a malonate into 3-substituted-2,2-dicyanocyclopropane-1,1-dicarboxylate—the first one-pot synthesis of a cyclopropane ring from three different molecules

Electrolysis of an aldehyde, malononitrile and a malonate in an alcohol in an undivided cell in the presence of sodium acetate-sodium halide as a double mediatory system results in the formation of 3-substituted-2,2-dicyanocyclopropane-1,1-dicarboxylates in 40-60% yields.     

Application of the thioimidate cyclopropane rearrangement to heterocyclic synthesis. Preparation of diaryl pyrrolines

Substituent effects on the thioimidate cyclopropane rearrangement and factors affecting regioselectivity are reported. Palladium-mediated coupling of the pyrrolothiomethylimidate rearrangement products with Grignard reagents provides diaryl pyrrolines in good yields.     

A theoretical study on the cyclopropane adsorption onto the copper surfaces by density functional theory and quantum chemical molecular dynamics methods

We report a theoretical study on the cyclopropane adsorption onto Cu(1 1 1) surfaces by density functional theory (DFT) and quantum chemical molecular dynamics methods. The equilibrium geometry of the physisorbed species was obtained using both periodic and cluster models by DFT methods that employ Cambridge serial total energy package (CASTEP), DMol ab initio quantum chemistry software of Accelrys’ materials studio (DMol), and Amsterdam density functional (ADF) program. It was found that the adsorbate molecule was tilted towards the metal surface with one C---C bond (upwards) parallel to the surface and that the physisorption occurred via a third carbon atom pointing (downwards) towards the surface. The electronic distribution and geometrical structure of physisorbed cyclopropane were slightly deviated from its gas phase molecule. The calculated vibrational frequencies and adsorption energies are close to experimental data, confirming the reliability of our DFT results. The adsorption process was simulated using our novel tight-binding quantum chemical molecular dynamics program, ‘Colors’. The calculation results indicated that both the adsorption and desorption processes of cyclopropane took place molecularly. The electron transfer and structural properties of equilibrium position obtained by ‘Colors’ are consistent with those by the first principles DFT methods.     

Multicomponent assembling of salicylaldehydes,malononitrile and cyanoacetamides: A simple and efficient approach to medicinally relevant 2-amino-4H-chromene scaffold

Sodium hydroxide catalyzed a new multicomponent reaction of salicylaldehydes, malononitrile and cyanoacetamides under ‘on-water’ conditions, which results in the facile and efficient formation of the corresponding substituted 2-amino-4H-chromenes in 80–95% yields. The convenient approach to the substituted 2-amino-4H-chromenes developed here — the promising small-molecule ligands for different biomedical applications with known spasmolitic, diuretic and antianaphylactic activities — is beneficial from the viewpoint of diversity-oriented large-scale processes and represents a fast, efficient and environmentally benign ‘on-water’ synthetic concept for multicomponent reactions strategy.     

Electro-oxidation of paracetamol in the presence of malononitrile: Application for green,efficient, none-catalyst,simple and one-pot electro-synthesis of new paracetamols

Electrochemical oxidation of paracetamol has been studied in the presence of malononitrile as a nucleophile in a phosphate buffer solution (0.15 mol/L, pH 7), using cyclic voltammetric techniques. The results indicated that the N-acetyl-p-benzoquinone-imine derived from paracetamol participates in a 1,4-Michael-type addition reaction with the malononitrile to form the corresponding paracetamol derivatives (6a, 7a). The present study has led to the development of a simple, green, non-catalyst and one-pot electrochemical method with high atom economy under mild conditions.     

Multicomponent assembling of salicylaldehydes,malononitrile, and 4-hydroxy-6-methyl-2H-pyran-2-one: A fast and efficient approach to medicinally relevant 2-amino-4H-chromene scaffold

A new multicomponent reaction (MCR) was found: a sodium acetate-catalyzed transformation of salicylaldehydes, malononitrile and 4-hydroxy-6-methyl-2H-pyran-2-one in ethanol results in the fast (30 min) and efficient formation of new 4-pyrano-substituted 2-amino-4H-chromenes in 86–96% yields. The same transformation initiated by grinding in mortar in the presence of sodium acetate or potassium fluoride results in a faster (15 min) formation of 4-pyrano-substituted 2-amino-4H-chromenes in 80–90% yields. This novel ‘one-pot’ process opens an effective and convenient way to pyrano-functionalized 2-amino-4H-chromene systems, which are promising compounds for different biomedical applications.     

Solvent-free cascade reaction: direct multicomponent assembling of 2-amino-4H-chromene scaffold from salicylaldehyde, malononitrile or cyanoacetate and nitroalkanes

The new type of solvent-free cascade reaction was found: the direct heating of the mixture of salicylaldehyde, malononitrile or cyanoacetate and nitroalkanes at 60 °C in the presence of catalytic amounts of KF or NaOAc results in the formation of 2-amino-4-(1-nitroalkyl)-4H-chromene-3-carbonitriles or methyl 2-amino-4-(1-nitroalkyl)-4H-chromene-3-carboxylates in 80-90% yields. Thus, the new simple and efficient solvent-free ‘one-pot’ way to substituted medicinally privileged 2-amino-4H-chromene scaffold was found directly from such simple and reasonable starting compounds as salicylaldehyde, malononitrile or cyanoacetate and nitroalkanes.     

A new strategy toward the total synthesis of stachyflin,a potent anti-influenza A virus agent: concise route to the tetracyclic core structure

[reaction: see text] A new strategy directed toward the total synthesis of stachyflin, a potent and novel anti-influenza A virus agent isolated from a microorganism, has been presented through the enantioselective synthesis of the tetracyclic core structure. The synthetic method features a BF(3) x Et(2)O-induced domino epoxide-opening/rearrangement/cyclization reaction as the key step.     

A New,Fast and Easy Strategy for One‐pot Synthesis of Full Substituted Cyclopropanes: Direct Transformation of Aldehydes to 3‐Aryl‐1,1,2,2‐tetracyanocyclopropanes

A new, fast and easy method for one‐pot reaction of aromatic aldehydes and dialdehydes with malononitrile and cyanogen bromide has been developed to afford full substituted 3‐arylcyclopropane‐1,1,2,2‐tetracarbonitriles in excellent yields in very short time (about 5 seconds). The structures elucidations werev characterized by IR, ¹H NMR, ¹³C NMR, mass spectrometry and X‐ray crystallography techniques. For vthese compounds the crystallographic data showed two structures in mirror image in solid case and one distinct structure in solution. The reaction mechanism was discussed.     

Stereoselective electrocatalytic transformation of arylidenemalononitriles and malononitrile into (1R,5S,6R)-6-aryl-2-amino-4,4-dialkoxy-1,5-dicyano-3-azabicyclo[3.1.0]hex-2-enes

Electrolysis of arylidenemalononitriles and malononitrile in alcohols in an undivided cell in the presence of sodium bromide as mediator results in the stereoselective formation of (1R,2S,6R)^*-6-aryl-2-amino-4,4-dialkoxy-1,5-dicyano-3-azabicyclo[3.1.0]hex-2-enes in 60-80% yields.     

Pseudo four-component reaction of salicylaldehydes and cyclic ketones with two molecules of malononitrile: A facile and efficient way to synthesize 4-[2-(dicyanomethylene)cyclic or heterocyclic]-2-amino-4H-chromenes

A new type of catalytic cascade pseudo four-component reaction has been found. The simple and facile pseudo four-component reaction of salicylaldehydes and cyclic or heterocyclic ketones with two molecules of malononitrile catalyzed by sodium acetate at ambient temperature results in the formation of 4-substituted 2-amino-4H-chromenes in 70–90% yields. Thus, a new simple and efficient ‘one-pot’ method to synthesize substituted 2-amino-4H-chromenes was found directly from such reasonable starting compounds as salicylaldehydes, cyclic or heterocyclic ketones and malononitrile.     

Triazolines IX. A new ring transformation reaction of a 4,5-acyl-substituted-1,2,3-triazoline: A new route to the synthesis of enamine and pyrrolidine ketones

A new ring transformation reaction of a 4,5-dibenzoyl-1,2,3-triazoline, which appears to involve nitrogen expulsion followed by a C-N proton shift, is described. The reaction affords a new route to the synthesis of enaminodiketones and tetraacylpyrrolidines, via triazoline intermediates.     

Unexpected stereoselective sodium acetate catalyzed multicomponent cyclization of aryl aldehydes, malononitrile and acetone into cis-4-dicyanomethylene-2,6-diarylcyclohexane-1,1-dicarbonitriles

A new type of multicomponent reaction is described in which five organic molecules form a cyclohexane ring. Aryl aldehydes, malononitrile and acetone in the presence of a catalytic amount of sodium acetate are stereoselectively cyclized into cis-4-dicyanomethylene-2,6-diarylcyclohexane-1,1-dicarbonitriles in 30-60% yields.     

A new chemical route to a hybrid nanostructure: room-temperature solid-state reaction synthesis of Ag@AgCl with efficient photocatalysis

The room-temperature solid-state chemical reaction technique has been used to synthesize the silver nanoparticle-loaded semiconductor silver@silver chloride for the first time. It has the advantages of convenient operation, lower cost, less pollution, and mass production. This simple technique created a wide array of nanosized silver particles which had a strong surface plasmon resonance effect in the visible region, and built up an excellent composite structure of silver@silver chloride hybrid which exhibited high photocatalytic activity and stability towards decomposition of organic methyl orange under visible-light illumination. Moreover, this work achieved the control of composition of the silver@silver chloride composite simply by adjusting the feed ratio of reactants. It offers an alternative method for synthesising metal@semiconductor composites.     

S-Methylation of polythiolactam: chemical transformation of macrocyclic anion receptor into new macrocyclic ligand for metal ions

The S-methylation of a macrocyclic tetrathiolactam afforded a new macrocyclic thioimidate that exhibited good affinity toward metal ions. The molecular structures of the macrocyclic ligand and its metal complexes were determined by X-ray crystallography.