Lucas Pizzuti

Efficient sonochemical synthesis of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides

An ultrasound-assisted preparation of a series of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides that proceeds via the efficient reaction of chalcones with aminoguanidine hydrochloride under clean conditions is described.

Environmentally friendly sonocatalysis promoted preparation of 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles

An efficient and green synthesis of thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles via the condensation of chalcones with thiosemicarbazide in ethanol and KOH under ultrasound irradiation is reported. The products were isolated in good yields after short reaction times.

Antioxidant capacity and environmentally friendly synthesis of dihydropyrimidin-(2H)-ones promoted by naturally occurring organic acids

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a β‐ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging assay and the thiobarbituric acid‐reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 µM. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds.

Ultrasound promoted greener synthesis of 2-(3,5-diaryl-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazoles

A rapid and cleaner procedure for the synthesis of a series of 2-(3,5-diaryl-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazoles under ultrasonic irradiation in ethanol is described.

Efficient synthesis of new 1-[Alkyl(aryl)]-5-(3,3,3-trihalo-2-oxopropylidene)pyrrolidin-2-ones

Reactions of methyl 4-methoxy-6-oxo-7,7,7-trihalo-4-heptenoates 1 and 2 with primary amines RNH2, where R = PhCH2, PhCH2CH2, Ph, 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, 4-BrC6H4, 2-pyridyl, 5-methyl-3-isoxazolyl, 4-NH2C6H4 affording methyl 4-[alkyl(aryl)amino]-6-oxo-7,7,7-trihalo-4-heptenoates 3, 4, in good yields (57-95%), which suffer quantitative intramolecular cyclocondensation to produce 1-alkyl(aryl)-5-(2-oxo-3,3,3-trihalopropylidene)pyrrolidin-2-ones 5, 6, are reported. The structures of the isolated new products were assigned by means of 1H, 13C NMR measurements and mass spectrometry. The Z and E configuration of compounds 3d and 5b respectively were established from X-ray crystallography.

Ultrasound promoted the synthesis of N-propargylic β-enaminones.

The synthesis of 14 novel N-propargylic β-enaminones from the reaction of β-alkoxy vinyltrihalomethyl[carboxyethyl] ketones [R(3)C(O)CHC(R(1))OMe, where R(3)=CF(3), CCl(3), CO(2)Et and R(1)=Me, Et, Pr, Bu, i-Pent, CH(2)CH(2)CO(2)Me] with propargyl amines [R(2)NHCH(2)CCH, where R(2)=Pr, PhCH(2)] is reported. Yields, solvents and reaction times needed for reaction completion, by microwave irradiation (MW), conventional thermal heating (TH) and under ultrasound irradiation (US) are compared. The best results were obtained under US irradiation in good to excellent yields (70-93%).

Recent advances on the green synthesis and antioxidant activities of pyrazoles.

Pyrazoles have a representative history in medicinal chemistry. These nucleuses, molecules of synthetic origin, constitute a group of nitrogen heterocyclic compounds. Available literature particularly shows a variety of pyrazoles with antioxidant effect. In this connection, this review describes the advances on the green synthesis of pyrazoles with antioxidant activity, mainly covering the data published over the last seven years (2008-2014).

Water as an Eco-friendly Solvent for Iodination Reactions of Aromatic and Heteroaromatic Compounds

In this review article we have gathered relatively recent publications involving modern methodologies for iodi- nation reactions of aromatic and heteroaromatic compounds using pure water or mixtures containing water as environ- mentally friendly media.

Synthesis of 6-(2-furyl) and 6-(2-thienyl)-4-trifluoromethylpyrimidinones and pyrimidines from 4-(2-heteroaryl)-4-methoxy-1,1,1-trifluoro-3-buten-2-ones

Neste trabalho e apresentada a sintese, em rendimentos razoaveis (50-67%), de novos sistemas biheterociclicos, duas 6-(2-heteroaril)-4-trifluormetil-2-(1H)-pirimidinonas (2a,b) e uma serie de dez 6-(2-heteroaril)-4-trifluormetilpirimidinas (3a,b - 7a,b) a partir da ciclocondensacao de 1,1,1-trifluor-4-(2-heteroaril)-4-metoxi-3-buten-2-onas com ureia e amidinas. As estruturas de todos os compostos foram atribuidas pelos dados de analise elementar, espectrometria de massas e dados de RMN 1 H e 13 C. Os dados de RMN 1 H e 13 C sao mostrados de maneira sistematica. Tambem apresentamos os dados de difracao de raios-X de um monocristal da 2-amino-6-(tien-2-il)-4-trifluormetilpirimidina (5b). The synthesis of biheterocyclic systems 6-(2-furyl)-pyrimidines and 6-(2-thienyl)pyrimidines in reasonable yields (50-67%), two 6-(2-heteroaryl)-4-trifluoromethyl-2-(1H)pyrimidinones (2a,b) and a series of ten 6-(2-heteroaryl)-4-trifluoromethylpyrimidines (3a,b 7a,b) from the cyclocondensation of 1,1,1-trifluoro-4-(2-heteroaryl)-4-methoxy-3-buten-2-ones with urea and amidines is reported. Structures of all compounds have been elucidated by elemental analysis, mass spectrometry and 1 H, 13 C NMR measurements. The 1 H and 13 C NMR data are systematically reported. The X-ray diffraction data for monocrystal from 2-amino-4trifluoromethyl-6-(thien-2-yl)-pyrimidine (5b) are reported.

Ultrasound-Promoted Environmentally Friendly Synthesis of 5-(3,3,3-Trifluoro-2-oxopropylidene)pyrrolidin-2-ones

Abstract A facile, one-pot, ultrasound-promoted synthesis of N-substituted 5-(3,3,3-trifluoro-2-oxopropylidene)pyrrolidin-2-ones from methyl 7,7,7-trifluoro-4-methoxy-6-oxohept-4-enoate and a wide range of primary alkyl(aryl)amines using ethanol as a green solvent and employing triethylamine as a base is described. GRAPHICAL ABSTRACT