Synthesis of new 3-cyanoacetamide pyrrole and 3-acetonitrile pyrrole derivatives

A new fused heterocyclic derivatives of pyrrole containing acetonitrile or cyanoacetonitrile moiety at 3-position is described by a one-pot multicomponent reaction. The reaction of dimedone, various aniline, aryl glyoxal with malononitrile/ethyl cyanoacetate/methyl cyanoacetate under mild conditions. The present method does not involve any hazardous organic solvents or catalysts. The significant features of this method are readily available starting materials, good yields, and easy purification.     

Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis

In this work, single‐piece fused silica capillaries with two different internal diameter segments featuring different inner surface roughness were prepared by new etching technology with supercritical water and used for volume coupling electrophoresis. The concept of separation and online pre‐concentration of analytes in high conductivity matrix is based on the online large‐volume sample pre‐concentration by the combination of transient isotachophoretic stacking and sweeping of charged proteins in micellar electrokinetic chromatography using non‐ionogenic surfactant. The modified surface roughness step helped to the significant narrowing of the zones of examined analytes. The sweeping and separating steps were accomplished simultaneously by the use of phosphate buffer (pH 7) containing ethanol, non‐ionogenic surfactant Brij 35, and polyethylene glycol (PEG 10000) after sample injection. Sample solution of a large volume (maximum 3.7 μL) dissolved in physiological saline solution was injected into the wider end of capillary with inlet inner diameter from 150, 185 or 218 μm. The calibration plots were linear (R ² ∼ 0.9993) over a 0.060–1 μg/mL range for the proteins used, albumin and cytochrome c. The peak area RSDs from at least 20 independent measuremens were below 3.2%. This online pre‐concentration technique produced a more than 196‐fold increase in sensitivity, and it can be applied for detection of, e.g . the presence of albumin in urine (0.060 μg/mL).     

Groebke-Blackburn-Bienaymé multicomponent reaction in scaffold-modification of adenine, guanine, and cytosine: synthesis of aminoimidazole-condensed nucleobases

A multicomponent method for scaffold-modification of nucleobases (adenine, guanine, and cytosine) was developed. This modification approach, as an alternative to usual synthetic routes involving protection-deprotection or S_NAr of halo (or leaving group-equivalent)-purines, affords in one step therapeutically-relevant substituted aminoimidazole-[i]-condensed adenine, [b]-condensed guanine, [c]-condensed cytosine. These derived nucleobases possess enhanced lipophilicity and solubility and contain the functionalities useful for further chemical manipulations.     

A new approach to fused furan ring systems and benzofurans: Intramolecular cyclization reactions of unsaturated acyloxy sulfone derivatives

Unsaturated acyloxy sulfones 3 undergo intramolecular cyclization upon deprotonation with LHMDS in THF. Dehydration and double bond isomerization of the products upon exposure to acid, gave the fused ring furans, 4, in good yields. This strategy could be readily adapted to prepare substituted benzofurans 12 from the cyclization reactions of acyloxy sulfones 11 prepared from phenols. Finally, this approach could be successfully modified to access dihydropyrans and benzopyrans.     

New four-component reactions in water: a convergent approach to the metal-free synthesis of spiro[indoline/acenaphthylene-3,4′-pyrazolo[3,4-b]pyridine derivatives

New four-component domino reactions are described that allow the one-pot synthesis of spiro[indoline/acenaphthylene-3,4′-pyrazolo[3,4-b]pyridine derivatives from the reaction of phenylhydrazine, 3-aminocrotononitrile, isatin/acenaphthylene-1,2-dione, and cyclic 1,3-dicarbonyl compounds, including cyclohexane-1,3-diones, barbituric acid, and 2-thioxodihydropyrimidine-4,6(1H,5H)-dione, in the presence of (±)-camphor-10-sulfonic acid (CSA). These processes take place in water and involve the generation of two rings and five new bonds (two C-C, two C-N and one CN) in a single synthetic operation, with expedient work-up and diminished waste generation due to the absence of extraction and purification steps.     

The versatile role of norbornene in C-H functionalization processes: concise synthesis of tetracyclic fused pyrroles via a threefold domino reaction

The synthesis of novel tetracyclic fused pyrroles from 1-(2-iodophenyl)-1H-pyrrole and various bromoalkyl-aryl alkynes via a palladium(0)-catalyzed and norbornene-mediated threefold domino reaction is reported. PdCl₂ and tri-2-furylphosphine (TFP) in the presence of norbornene and Cs₂CO₃ in CH₃CN at 90 °C gave a variety of tetracyclic fused pyrroles in usually high yields. In the described reaction sequence two of the three carbon-carbon bonds are formed by functionalization of an unactivated aryl C-H bond.     

Analysis of mutagenic amino acid pyrolyzates with a fused silica capillary column

In this study, application of a fused silica capillary column for analysis of major mutagenic heterocyclic compounds found in cooked foods was investigated.