Mild and direct conversion of quinoline N-oxides to 2-amidoquinolines with primary amides

[reaction: see text] A simple, one-pot procedure is described for the direct conversion of quinoline N-oxides to alpha-amidoquinolines with primary amides. This methodology is complimentary to the Abramovich reaction, which is limited to the introduction of secondary amides via imidoyl chlorides. Although reaction conditions are quite similar, omission of the base is key for successful reaction with primary amides, which were found not to proceed through the intermediacy of an imidoyl chloride but rather through an acyl isocyanate.     

Structural and thermodynamic properties and intermolecular interactions in aqueous and acetonitrile solutions of aprotic amides

The structural and thermodynamic properties are calculated for mixtures of aprotic amides with water and acetonitrile. The simulation approach is used to identify the specific and nonspecific components of the total energy of intermolecular interactions, which are used to calculate the corresponding contributions to the enthalpy of mixing. The negative enthalpies of mixing in the aqueous mixtures are found to be caused not by heterocomponent specific interactions, but by nonspecific ones. The difference in the structural and thermodynamic properties of the aqueous and nonaqueous mixtures of aprotic amides is shown to be largely due to the behavior of the hydrogen bond network of water and the packing of the resulting solutions.     

Heterogeneously catalyzed synthesis of primary amides directly from primary alcohols and aqueous ammonia

In the presence of a manganese oxide based octahedral molecular sieve (OMS-2), a range of primary amides could be synthesized directly from primary alcohols and ammonia. The observed catalysis was heterogeneous, and the recovered catalyst could be reused many times without an appreciable loss of its catalytic performance.     

Oxygen-promoted PdCl2-catalyzed ligand-free Suzuki reaction in aqueous media

A simple and efficient protocol has been developed for the PdCl(2)-catalyzed ligand-free and aerobic Suzuki reaction of aryl bromides or nitrogen-based heteroaryl bromides with arylboronic acids in good to excellent yields in aqueous ethanol. A systematic investigation on the effect of different atmospheres on the reactivity of the palladium-catalyzed Suzuki reaction has been carried out, the results show that an aerobic atmosphere demonstrates a positive effect on the reactivity of the Suzuki reaction in an aqueous media and a negative effect in a pure organic solvent, which exhibits that the water plays a crucial role for the function of the atmosphere on the palladium-catalyzed ligand-free Suzuki reaction.     

Efficient dehydration of primary amides to nitriles catalyzed by phosphorus-chalcogen chelated iron hydrides

A series of phosphorus-chalcogen chelated hydrido iron (II) complexes 1–7 , (o-(R'₂P)-p-R-C₆H₄Y)FeH (PMe₃)₃ ( 1 : R = H, R' = Ph, Y = O; 2 : R = Me, R' = Ph, Y = O; 3 : R = H, R' = ⁱPr, Y = O; 4 : R = Me, R' = ⁱPr, Y = O; 5 : R = H, R' = Ph, Y = S; 6 : R = Me, R' = Ph, Y = S; 7 : R = H, R' = Ph, Y = Se), were synthesized. The catalytic performances of 1–7 for dehydration of amides to nitriles were explored by comparing three factors: (1) different chalcogen coordination atoms Y; (2) R' group of the phosphine moiety; (3) R substituent group at the phenyl ring. It is confirmed that 5 with S as coordination atom has the best catalytic activity and 7 with Se as coordination atom has the poorest catalytic activity among complexes 1 , 5 and 7 . Electron-rich complex 4 is the best catalyst among the seven complexes and the dehydration reaction was completed by using 2 mol% catalyst loading at 60 °C with 24 hr in the presence of (EtO)₃SiH in THF. Catalyst 4 has good tolerance to many functional groups. Among the seven iron complexes, new complexes 3 and 4 were obtained via the O-H bond activation of the preligands o-ⁱPr₂P(C₆H₄)OH and o-ⁱPr₂P-p-Me-(C₆H₄)OH by Fe(PMe₃)₄. Both 3 and 4 were characterized by spectroscopic methods and X-ray diffraction analysis. The catalytic mechanism was experimentally studied and also proposed.     

Mercury-catalyzed rearrangement of ketoximes into amides and lactams in acetonitrile

An acetonitrile solution of mercury(II) chloride has been found to catalyze efficiently the conversion of a diverse range of ketoximes into their corresponding amides/lactams.     

Enthalpy characteristics of dilute solutions of amides in acetonitrile

The enthalpy of mixing of formamide,N-methylformamide,N,N-dimethylformamide, and hexamethylphosphoric triamide with MeCN was measured in the 283–328 K range. The enthalpic coefficients of the binary and ternary interactions between the amide molecules are calculated within the framework of the McMillan-Mayer theory. The contributions to the enthalpy of dissolution due to cavity formation in the solvent (Δ_cav H ⁰) and due to solute-solvent interaction (Δ_int H ⁰) were determined. The enthalpies of specific and nonspecific solvation of amides in MeCN were calculated. The main contribution to the enthalpy of solvation of formamide andN-methylformamide is from specific interactions, while forN,N-dimethylformamide and hexamethylphosphoric triamide it is from nonspecific interactions. The values obtained are compared with those for solutions of the amides mentioned in water and methanol. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1730–1735, October, 1993.     

Electrochemistry of copper in aqueous acetonitrile

The electrochemical characteristics of the Cu (II)/Cu (I) and the Cu (I)/Cu (0) couples at platinum, carbon, mercury and copper have been studied in acetonitrile-water (AN-H₂O) mixtures. All the electrode processes are moderately fast with mercury the fastest but slower on platinum and carbon paste in that order. A slow chemical step precedes oxidation of Cu (I) to Cu (II) on allectrodes in solutions of high AN content. The slow step may be partial removal of AN from the solvated Cu (I) ion prior to electron transfer. Electrode processes are faster in chloride ions than in sulfate ion solutions. Reduction of Cu (I) in AN–H₂O is quite slow on glassy carbon. Adsorption of AN on platinum and carbon influences the processes. Diffusion coefficients in sulfate solutions are in the order, Cu (I) (AN–H₂O)>Cu (II)(AN–H₂O)>Fe (III)(H₂O) and 2-hydroxy-cyanoethane (2-HCE) strongly decreases the mobility of Cu (I) when added to H₂O. The relevance of the measurements to hydrometallurgical processes is considered. CuSO₄ in 30% v/v AN–H₂O is a faster oxidant than the common oxidant Fe₂(SO₄)₃ in H₂O because of the greater mobility and faster electron acceptance from a corroding surface of Cu (II). Only in solutions of very high nitrile content is the reduction potential of CuSO₄ as high as that of Fe₂(SO₄)₃ in H₂O.     

Mild and efficient synthesis of (Z)-alpha-chloroalkylidene-beta-lactones via the PdCl2-catalyzed cyclocarbonylation of 2-alkynols

[reaction: see text] A mild and efficient methodology involving PdCl(2)-catalyzed cyclocarbonylation of 2-alkynols with CuCl(2) for the synthesis of (Z)-alpha-chloroalkylidene-beta-lactones was developed. Using the readily available optically active propargylic alcohols allows convenient synthesis of the corresponding (Z)-alpha-chloroalkylidene-beta-lactones with high ee values. cis-Chloropalladation was observed as the major pathway, which is unique as compared to the reported data.     

Mild N-deacylation of secondary amides by alkylation with organocerium reagents

Secondary amides are a class of highly stable compounds serving as versatile starting materials, intermediates and directing groups (amido groups) in organic synthesis. The direct deacylation of secondary amides to release amines is an important transformation in organic synthesis. Here, we report a protocol for the deacylation of secondary amides and isolation of amines. The method is based on the activation of amides with Tf₂O, followed by addition of organocerium reagents, and acidic work-up. The reaction proceeded under mild conditions and afforded the corresponding amines, isolated as their hydrochloride salts, in good yields. In combination with the C-H activation functionalization methodology, the method is applicable to the functionalization of aniline as well as conversion of carboxylic derivatives to functionalized ketones.     

Decomposition of Analgin in aqueous acetonitrile solutions

The stability of Analgin in aqueous acetonitrile solutions was studied depending on the concentrations of acetonitrile and stabilizer (sodium sulfite) and the pH of the solution. It was shown that the concentration of the organic solvent had the most effect on the decomposition rate. The results obtained can be used to develop procedures for determining Analgin and in pharmacology and medicine to improve the stability of Analgin-containing formulations.     

Enthalpy of dilution of aqueous systems containing S-trioxane and some amides. Analysis of the interaction of saccharides with amides in aqueous media

Enthalpies of dilution of aqueous systems of trioxane+formamide and trioxane+dimethylformamide have been determined at 25°C. The data have been treated in terms of the Savage-Wood additivity principle, and a first estimate of the pairwise group interaction enthalpy for-O-/CONH is presented. Systems of saccharides and amides are not amenable to the Savage-Wood treatment used in recent works. However, when treated in conjunction with all available data to yield a different set of group interaction parameters, saccharides behave more predictably. Implications of this state of affairs are considered.     

Mild regioselective phosphorylation of β-cyclodextrin with trivalent phosphorus acid amides

Phosphorylation of β-cyclodextrin with trivalent phosphorus acid diamides in pyridine is found to proceed selectively at primary hydroxy groups under mild conditions (20°C) due to the supramolecular effect of the cyclodextrin cavity. The compounds obtained are of practical interest for further synthesis on their basis of amphiphilic glycophospholipids immobilized on the cyclodextrin matrix.     

PdCl2-catalyzed hydrogenolysis of an Ar-Cl bond by sodium phosphinate in an aqueous alkaline medium

The hydrogenolysis of the Ar-Cl bond in chlorinated benzoic acids, anilines, and nitrogen-containing heterocycles by the action of NaH₂PO₂ in the presence of catalytic amounts of PdCl₂ and NaOH in an aqueous medium was studied. Under these conditions aryl chlorides were quantitatively converted into the corresponding arenes. Chloropyridines, such as 2-chloropyridine and 3, 5-dichloropicolinic acid, did not undergo hydrogenolysis even in the presence of an equivalent amount of NaI. A distinctortho effect was observed forortho-substituted substrates.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 607–609, March, 1993.