Paolino Filippone

Selective oxidation of phenol and anisole derivatives to quinones with hydrogen peroxide and polymer-supported methylrhenium trioxide systems

Abstract A convenient and efficient application of heterogeneous poly(4-vinylpyridine)/methyl rhenium trioxide (PVP/MTO) systems for the selective oxidation of substituted phenol and anisole derivatives to benzoquinones is described. Environment friendly, easily available, and low cost H 2 O 2 was used as the oxygen atom donor. All catalysts were stable systems for at least five recycling experiments. In the oxidation of some natural phenols such as cardanol derivatives higher conversion and yields of benzoquinones were observed with respect to MTO in homogeneous phase suggesting a support-mediated molecular recognition process based on hydrogen-bonding interactions.

Polycrystalline TiO2 impregnated with cardanol-based porphyrins for the photocatalytic degradation of 4-nitrophenol

Hydrogenated cardanol (3-n-pentadecylphenol), a renewable organic resource obtained by vacuum distillation of roasted “cashew nut shell liquid” (CNSL), a by-product of the cashew industry, has been used to synthesize novel lipophilic porphyrins. Polycrystalline TiO2 impregnated with these novel “cardanol-based” porphyrins as sensitizers has been investigated in the photodegradation of 4-nitrophenol (4-NP) in aqueous suspension. The results indicated that the presence of the sensitizer enhances the photoactivity of polycrystalline bare TiO2 in the process. The activating effect was higher in the case of the Cu-complex.

Copper(II)/Copper(I)-Catalyzed Aza-Michael Addition/Click Reaction of in Situ Generated α-Azidohydrazones: Synthesis of Novel Pyrazolone−Triazole Framework

A one-pot Cu(II)-catalyzed aza-Michael addition of trimethylsilyl azide to 1,2-diaza-1,3-dienes and Cu(I)-catalyzed 1,3-dipolar cycloaddition of in situ generated alpha-azidohydrazones with alkynes is reported. This process combining two consecutive steps with recycling of the catalyst (Cu(OAc)(2).H(2)O) represents a useful protocol for the smooth synthesis of novel pyrazolone-triazole derivatives.

An Efficient One-Pot, Three-Component Synthesis of 5-Hydrazinoalkylidene Rhodanines from 1,2-Diaza-1,3-dienes

A novel three-component synthesis of 5-hydrazinoalkylidene rhodanine derivatives starting from aliphatic primary amines, carbon disulfide, and 1,2-diaza-1,3-dienes is described. The reaction proceeds successfully under both solution and solid-phase conditions.

Effect of Metal Ions in Organic Synthesis. part XVI. Knoevenagel Condensations of Aldehydes and Tosylhydrazones with 2,4-Pentanedione by Copper (II) Chloride-Catalyzed Reaction

Abstract Based on some of our previous findings on the activity of some metal ions in certain organic reactivities,1 we have now studied the Knoevenagel condensations of aliphatic and aromatic aldehydes or their tosylhydrazone derivatives with 2,4-pentanedione. In the presence of catalytic amounts of anhydrous copper (II) chloride, these compounds react in tetrahydrofuran at room temperature, affording the corresponding alkylidene or arylidene compounds in 48–98% yields.

A Novel and Convenient Protocol for Synthesis of Pyridazines

A new flexible strategy for the synthesis of diversely functionalized pyridazines from 4-chloro-1,2-diaza-1,3-butadienes and active methylene compounds is reported. The high chemoselectivity of this approach offers access to structural precursors of GABA-A antagonist analogues.

Flexible protocol for the chemo- and regioselective building of pyrroles and pyrazoles by reactions of Danishefsky's dienes with 1,2-diaza-1,3-butadienes.

The versatility of the Mukaiyama-Michael-type addition/heterocyclization of Danishefskys diene with 1,2-diaza-1,3-butadienes was applied to the synthesis of both 4 H-1-aminopyrroles and 4,5 H-pyrazoles. Thus, the same reagents furnished different types of highly functionalized azaheterocycles essentially depending on their structure: as a matter of fact, R1 = COOR or CONR 2 differently affects the acidity of the proton at the adjacent carbon. An unexpected formation of 5 H-1-aminopyrroles from the reactions carried out in water was also observed.

Absolute rate constants for the reaction of peroxyl radicals with cardanol derivatives

Industrial grade cardanol is a yellow oil containing mostly cardanol with smaller percentages of cardol and methylcardol, obtained by thermal treatment and subsequent distillation of cashew nut shell liquid available in large amounts in some developing countries. In order to find useful applications of this widely available and renewable raw material in fine chemical processes we undertook a kinetic investigation of the antioxidant activity of some hydrogenated cardanol and cardol derivatives, compared with that of analogous commercial products.

Synthesis, reaction, theoretical calculation, NMR study and X-ray crystal structure of 1-substituted and 1-unsubstituted 1H-pyrazol-5(2H)-ones

Abstract 1-Substituted 4-alkoxy-, 4-alkylthio-, and 4-aryloxy-1H-pyrazol-5(2H)-ones have been prepared by the reaction of conjugated azoalkenes with alcohols, thiols, and phenols. In some cases the intermediate hydrazones were isolated, while in others the products were obtained in one step. 1-Unsubstituted 4-alkoxy-, 4-alkylthio-, and 4-aryloxy-1H-pyrazol-5(2H)-ones were produced by methanolysis of the corresponding 1-substituted derivatives under reflux. Some of these compounds were studied by molecular mechanics calculations, as well as deuterium induced shifts (DIS) on 13C chemical shifts, and tentative conclusion was drawn about their tautomerism and conformations. X-Ray crystal structure determinations of 1-(aminocarbonyl)-3-methyl-4-methoxy-1H-pyrazol-5(2H)-one 4e and 3-methyl-4-methoxy-1H-pyrazol-5(2H)-one 5a demonstrated that both molecules exist in the crystal exclusively in the HN-CO tautomeric form. Some previously reported structural assignments in some pyrazolones and hydroxypyrazoles were corrected.

PEG-immobilization of cardol and soluble polymer-supported synthesis of some cardol–coumarin derivatives: Preliminary evaluation of their inhibitory activity on mushroom tyrosinase

In this work, the PEG-immobilization and the liquid phase synthesis of some coumarins derived from cardol are presented. Some preliminary results on their tyrosinase inhibitory activity are also included.